AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/09/15 11:08	flow	patch-triage	14m Args: null Results: { "EnableConfigs": [ "SND_USB_AUDIO", "MOUSE_SYNAPTICS_USB", "SUNRPC", "COMEDI_BOND", "COMEDI_MISC_DRIVERS", "COMEDI", "FORTIFY_SOURCE" ], "FocusSymbols": [ "usb_audio_make_longname", "snd_usb_audio_create", "build_connector_control", "synusb_probe", "rpc_sockaddr2uaddr", "devlink_compat_running_version", "bonding_attach" ], "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false, "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.", "WorthFuzzing": true }
1/1	2026/09/15 11:08	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 7af038477662f04c34c484a45e1a571280e5f258\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Tue Sep 15 11:08:01 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c\nindex 4ec591bde3dfa..21140b44d96e6 100644\n--- a/arch/arm/kernel/atags_parse.c\n+++ b/arch/arm/kernel/atags_parse.c\n@@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision);\n static int __init parse_tag_cmdline(const struct tag tag)\n {\n #if defined(CONFIG_CMDLINE_EXTEND)\n-\tstrlcat(default_command_line, \" \", COMMAND_LINE_SIZE);\n-\tstrlcat(default_command_line, tag-\u003eu.cmdline.cmdline,\n-\t\tCOMMAND_LINE_SIZE);\n+\tsize_t len = strlen(default_command_line);\n+\n+\tsnprintf(default_command_line + len, COMMAND_LINE_SIZE - len,\n+\t\t \" %s\", tag-\u003eu.cmdline.cmdline);\n #elif defined(CONFIG_CMDLINE_FORCE)\n \tpr_warn(\"Ignoring tag cmdline (using the default kernel command line)\\n\");\n #else\ndiff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c\nindex 6fa4a22a58fd6..826396f141b9c 100644\n--- a/arch/loongarch/kernel/setup.c\n+++ b/arch/loongarch/kernel/setup.c\n@@ -33,6 +33,7 @@\n #include \u003clinux/of_address.h\u003e\n #include \u003clinux/suspend.h\u003e\n #include \u003clinux/swiotlb.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003casm/addrspace.h\u003e\n #include \u003casm/alternative.h\u003e\n@@ -305,6 +306,8 @@ static void __init fdt_setup(void)\n \n static void __init bootcmdline_init(char cmdline_p)\n {\n+\tstruct seq_buf s;\n+\n \t/\n \t * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line\n \t * is trivial - we simply use the built-in command line unconditionally \u0026\n@@ -315,6 +318,11 @@ static void __init bootcmdline_init(char *cmdline_p)\n \t\tgoto out;\n \t}\n \n+\t/ Initialize seq_buf pointing to boot_command_line /\n+\ts.buffer = boot_command_line;\n+\ts.size = COMMAND_LINE_SIZE;\n+\ts.len = strlen(boot_command_line);\n+\n #ifdef CONFIG_OF_FLATTREE\n \t/\n \t * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system,\n@@ -323,11 +331,11 @@ static void __init bootcmdline_init(char *cmdline_p)\n \t to boot_command_line.\n \t /\n \tif (initial_boot_params) {\n-\t\tif (boot_command_line[0])\n-\t\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n+\t\tif (s.len)\n+\t\t\tseq_buf_puts(\u0026s, \" \");\n \n-\t\tif (!strstr(boot_command_line, init_command_line))\n-\t\t\tstrlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE);\n+\t\tif (!strstr(s.buffer, init_command_line))\n+\t\t\tseq_buf_puts(\u0026s, init_command_line);\n \n \t\tgoto out;\n \t}\n@@ -338,14 +346,14 @@ static void __init bootcmdline_init(char cmdline_p)\n \t CONFIG_CMDLINE_EXTEND is enabled.\n \t /\n \tif (IS_ENABLED(CONFIG_CMDLINE_EXTEND) \u0026\u0026 CONFIG_CMDLINE[0]) {\n-\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n-\t\tstrlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n+\t\tseq_buf_puts(\u0026s, \" \");\n+\t\tseq_buf_puts(\u0026s, CONFIG_CMDLINE);\n \t}\n \n \t/\n \t * Use built-in command line if the bootloader command line is empty.\n \t /\n-\tif (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) \u0026\u0026 !boot_command_line[0])\n+\tif (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) \u0026\u0026 !s.len)\n \t\tstrscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n \n out:\ndiff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c\nindex 1ae6d0c0e1d67..0d9c2137d6758 100644\n--- a/arch/mips/kernel/setup.c\n+++ b/arch/mips/kernel/setup.c\n@@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void)\n \n static void __init bootcmdline_append(const char s, size_t max)\n {\n+\tsize_t len;\n+\tint prec;\n+\n \tif (!s[0] \|\| !max)\n \t\treturn;\n \n-\tif (boot_command_line[0])\n-\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n+\tlen = strlen(boot_command_line);\n+\tif (len \u003e= COMMAND_LINE_SIZE - 1)\n+\t\treturn;\n \n-\tstrlcat(boot_command_line, s, max);\n+\tif (len) {\n+\t\tif (COMMAND_LINE_SIZE - len \u003c 3)\n+\t\t\treturn;\n+\n+\t\tprec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2);\n+\t\tsnprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, \" %.s\",\n+\t\t\t prec, s);\n+\t} else {\n+\t\tprec = min_t(size_t, max, COMMAND_LINE_SIZE - 1);\n+\t\tsnprintf(boot_command_line, COMMAND_LINE_SIZE, \"%.s\",\n+\t\t\t prec, s);\n+\t}\n }\n \n #ifdef CONFIG_OF_EARLY_FLATTREE\ndiff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c\nindex d3e17a7a89016..fa3efc82ad874 100644\n--- a/arch/parisc/kernel/setup.c\n+++ b/arch/parisc/kernel/setup.c\n@@ -17,6 +17,7 @@\n #include \u003clinux/init.h\u003e\n #include \u003clinux/console.h\u003e\n #include \u003clinux/seq_file.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #define PCI_DEBUG\n #include \u003clinux/pci.h\u003e\n #undef PCI_DEBUG\n@@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE];\n static void __init setup_cmdline(char *cmdline_p)\n {\n \textern unsigned int boot_args[];\n+\tstruct seq_buf s;\n \tchar p;\n \n \tcmdline_p = command_line;\n@@ -54,19 +56,21 @@ static void __init setup_cmdline(char cmdline_p)\n \tstrscpy(boot_command_line, (char )__va(boot_args[1]),\n \t\tCOMMAND_LINE_SIZE);\n \n+\ts.buffer = boot_command_line;\n+\ts.size = COMMAND_LINE_SIZE;\n+\ts.len = strlen(boot_command_line);\n+\n \t/* autodetect console type (if not done by palo yet) /\n \tp = boot_command_line;\n \tif (!str_has_prefix(p, \"console=\") \u0026\u0026 !strstr(p, \" console=\")) {\n-\t\tstrlcat(p, \" console=\", COMMAND_LINE_SIZE);\n-\t\tif (PAGE0-\u003emem_cons.cl_class == CL_DUPLEX)\n-\t\t\tstrlcat(p, \"ttyS0\", COMMAND_LINE_SIZE);\n-\t\telse\n-\t\t\tstrlcat(p, \"tty0\", COMMAND_LINE_SIZE);\n+\t\tseq_buf_printf(\u0026s, \" console=%s\",\n+\t\t\t PAGE0-\u003emem_cons.cl_class == CL_DUPLEX ?\n+\t\t\t \"ttyS0\" : \"tty0\");\n \t}\n \n \t/ default to use early console /\n \tif (!strstr(p, \"earlycon\"))\n-\t\tstrlcat(p, \" earlycon=pdc\", COMMAND_LINE_SIZE);\n+\t\tseq_buf_printf(\u0026s, \" earlycon=pdc\");\n \n #ifdef CONFIG_BLK_DEV_INITRD\n \t/ did palo pass us a ramdisk? /\ndiff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c\nindex cda6adb9f69c4..c40e0edd7c136 100644\n--- a/arch/x86/kernel/setup.c\n+++ b/arch/x86/kernel/setup.c\n@@ -916,9 +916,11 @@ void __init setup_arch(char cmdline_p)\n #else\n \tif (builtin_cmdline[0]) {\n \t\t/ append boot loader cmdline to builtin /\n-\t\tstrlcat(builtin_cmdline, \" \", COMMAND_LINE_SIZE);\n-\t\tstrlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);\n-\t\tstrscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);\n+\t\tchar tmp[COMMAND_LINE_SIZE];\n+\n+\t\tsnprintf(tmp, COMMAND_LINE_SIZE, \"%s %s\", builtin_cmdline, boot_command_line);\n+\t\tstrscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE);\n+\t\tstrscpy(boot_command_line, tmp, COMMAND_LINE_SIZE);\n \t}\n #endif\n \tbuiltin_cmdline_added = true;\ndiff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c\nindex 8e10ecab4f0dc..a10cfbd04c728 100644\n--- a/drivers/comedi/drivers/comedi_bond.c\n+++ b/drivers/comedi/drivers/comedi_bond.c\n@@ -39,6 +39,7 @@\n \n #include \u003clinux/module.h\u003e\n #include \u003clinux/string.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/slab.h\u003e\n #include \u003clinux/comedi.h\u003e\n #include \u003clinux/comedi/comedilib.h\u003e\n@@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\n {\n \tstruct comedi_bond_private devpriv = dev-\u003eprivate;\n \tDECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);\n+\tstruct seq_buf s;\n \tint i;\n \n \tmemset(\u0026devs_opened, 0, sizeof(devs_opened));\n-\tdevpriv-\u003ename[0] = 0;\n+\tseq_buf_init(\u0026s, devpriv-\u003ename, sizeof(devpriv-\u003ename));\n \t/\n \t Loop through all comedi devices specified on the command-line,\n \t * building our device list.\n@@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\n \t\t\t}\n \t\t\tdevpriv-\u003edevs = devs;\n \t\t\tdevpriv-\u003edevs[devpriv-\u003endevs++] = bdev;\n-\t\t\t{\n-\t\t\t\t/* Append dev:subdev to devpriv-\u003ename /\n-\t\t\t\tchar buf[20];\n-\n-\t\t\t\tsnprintf(buf, sizeof(buf), \"%u:%u \",\n-\t\t\t\t\t bdev-\u003eminor, bdev-\u003esubdev);\n-\t\t\t\tstrlcat(devpriv-\u003ename, buf,\n-\t\t\t\t\tsizeof(devpriv-\u003ename));\n-\t\t\t}\n+\n+\t\t\t/ Append dev:subdev to devpriv-\u003ename /\n+\t\t\tseq_buf_printf(\u0026s, \"%u:%u \", bdev-\u003eminor, bdev-\u003esubdev);\n \t\t}\n \t}\n \n@@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\n \t\treturn -EINVAL;\n \t}\n \n+\tseq_buf_str(\u0026s);\n+\n \treturn 0;\n }\n \ndiff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c\nindex 9c0a1e48f96f2..4e3781815b6d7 100644\n--- a/drivers/edac/thunderx_edac.c\n+++ b/drivers/edac/thunderx_edac.c\n@@ -20,6 +20,7 @@\n #include \u003clinux/atomic.h\u003e\n #include \u003clinux/bitfield.h\u003e\n #include \u003clinux/circ_buf.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003casm/page.h\u003e\n \n@@ -47,12 +48,17 @@ static void decode_register(char str, size_t size,\n {\n \tint ret = 0;\n \n+\tif (size \u003e 0)\n+\t\tstr[0] = '\\0';\n+\n \twhile (descr-\u003etype \u0026\u0026 descr-\u003emask \u0026\u0026 descr-\u003edescr) {\n \t\tif (reg \u0026 descr-\u003emask) {\n \t\t\tret = snprintf(str, size, \"\\n\\t%s, %s\",\n \t\t\t\t descr-\u003etype == ERR_CORRECTED ?\n \t\t\t\t\t \"Corrected\" : \"Uncorrected\",\n \t\t\t\t descr-\u003edescr);\n+\t\t\tif (ret \u003c 0 \|\| ret \u003e= size)\n+\t\t\t\tbreak;\n \t\t\tstr += ret;\n \t\t\tsize -= ret;\n \t\t}\n@@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void irq_id)\n \n \twhile (CIRC_CNT(ocx-\u003ecom_ring_head, ocx-\u003ecom_ring_tail,\n \t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx))) {\n+\t\tstruct seq_buf s;\n+\n \t\ttail = ring_pos(ocx-\u003ecom_ring_tail,\n \t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx));\n \t\tctx = \u0026ocx-\u003ecom_err_ctx[tail];\n \n-\t\tsnprintf(msg, OCX_MESSAGE_SIZE, \"%s: OCX_COM_INT: %016llx\",\n-\t\t\tocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n+\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_INT: %016llx\",\n+\t\t\t ocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n \n \t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\tocx_com_errors, ctx-\u003ereg_com_int);\n \n-\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tfor (lane = 0; lane \u003c OCX_RX_LANES; lane++)\n \t\t\tif (ctx-\u003ereg_com_int \u0026 BIT(lane)) {\n-\t\t\t\tsnprintf(other, OCX_OTHER_SIZE,\n-\t\t\t\t\t \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n-\t\t\t\t\t lane, ctx-\u003ereg_lane_int[lane],\n-\t\t\t\t\t lane, ctx-\u003ereg_lane_stat11[lane]);\n-\n-\t\t\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\t\t\tseq_buf_printf(\u0026s,\n+\t\t\t\t\t \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n+\t\t\t\t\t lane, ctx-\u003ereg_lane_int[lane],\n+\t\t\t\t\t lane, ctx-\u003ereg_lane_stat11[lane]);\n \n \t\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\t\t\tocx_lane_errors,\n \t\t\t\t\t\tctx-\u003ereg_lane_int[lane]);\n-\t\t\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\t\t\tseq_buf_puts(\u0026s, other);\n \t\t\t}\n \n \t\tif (ctx-\u003ereg_com_int \u0026 OCX_COM_INT_CE)\n-\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tocx-\u003ecom_ring_tail++;\n \t}\n@@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void irq_id)\n \n \twhile (CIRC_CNT(ocx-\u003elink_ring_head, ocx-\u003elink_ring_tail,\n \t\t\tARRAY_SIZE(ocx-\u003elink_err_ctx))) {\n+\t\tstruct seq_buf s;\n+\n \t\ttail = ring_pos(ocx-\u003elink_ring_head,\n \t\t\t\tARRAY_SIZE(ocx-\u003elink_err_ctx));\n \n \t\tctx = \u0026ocx-\u003elink_err_ctx[tail];\n \n-\t\tsnprintf(msg, OCX_MESSAGE_SIZE,\n-\t\t\t \"%s: OCX_COM_LINK_INT[%d]: %016llx\",\n-\t\t\t ocx-\u003eedac_dev-\u003ectl_name,\n-\t\t\t ctx-\u003elink, ctx-\u003ereg_com_link_int);\n+\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_LINK_INT[%d]: %016llx\",\n+\t\t\t ocx-\u003eedac_dev-\u003ectl_name,\n+\t\t\t ctx-\u003elink, ctx-\u003ereg_com_link_int);\n \n \t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\tocx_com_link_errors, ctx-\u003ereg_com_link_int);\n \n-\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tif (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_UE)\n-\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \t\telse if (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_CE)\n-\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tocx-\u003elink_ring_tail++;\n \t}\n@@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void irq_id)\n \n \twhile (CIRC_CNT(l2c-\u003ering_head, l2c-\u003ering_tail,\n \t\t\tARRAY_SIZE(l2c-\u003eerr_ctx))) {\n-\t\tsnprintf(msg, L2C_MESSAGE_SIZE,\n-\t\t\t \"%s: %s: %016llx, %s: %016llx\",\n-\t\t\t l2c-\u003eedac_dev-\u003ectl_name, reg_int_name, ctx-\u003ereg_int,\n-\t\t\t ctx-\u003ereg_ext_name, ctx-\u003ereg_ext);\n+\t\tstruct seq_buf s;\n+\n+\t\ttail = ring_pos(l2c-\u003ering_tail, ARRAY_SIZE(l2c-\u003eerr_ctx));\n+\t\tctx = \u0026l2c-\u003eerr_ctx[tail];\n+\n+\t\tseq_buf_init(\u0026s, msg, L2C_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: %s: %016llx, %s: %016llx\",\n+\t\t\t l2c-\u003eedac_dev-\u003ectl_name, reg_int_name, ctx-\u003ereg_int,\n+\t\t\t ctx-\u003ereg_ext_name, ctx-\u003ereg_ext);\n \n \t\tdecode_register(other, L2C_OTHER_SIZE, l2_errors, ctx-\u003ereg_int);\n \n-\t\tstrlcat(msg, other, L2C_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tif (ctx-\u003ereg_int \u0026 mask_ue)\n-\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \t\telse if (ctx-\u003ereg_int \u0026 mask_ce)\n-\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tl2c-\u003ering_tail++;\n \t}\ndiff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c\nindex 7ce9e212770ad..229b5fec44bff 100644\n--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c\n+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c\n@@ -29,6 +29,7 @@\n #include \u003clinux/kernel.h\u003e\n #include \u003clinux/random.h\u003e\n #include \u003clinux/sched.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/seq_file.h\u003e\n \n #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)\n@@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch mstb,\n \t\t\t\tchar proppath,\n \t\t\t\tsize_t proppath_size)\n {\n+\tstruct seq_buf s;\n \tint i;\n-\tchar temp[8];\n \n-\tsnprintf(proppath, proppath_size, \"mst:%d\", mstb-\u003emgr-\u003econn_base_id);\n+\tseq_buf_init(\u0026s, proppath, proppath_size);\n+\n+\tseq_buf_printf(\u0026s, \"mst:%d\", mstb-\u003emgr-\u003econn_base_id);\n \tfor (i = 0; i \u003c (mstb-\u003elct - 1); i++) {\n \t\tint shift = (i % 2) ? 0 : 4;\n \t\tint port_num = (mstb-\u003erad[i / 2] \u003e\u003e shift) \u0026 0xf;\n \n-\t\tsnprintf(temp, sizeof(temp), \"-%d\", port_num);\n-\t\tstrlcat(proppath, temp, proppath_size);\n+\t\tseq_buf_printf(\u0026s, \"-%d\", port_num);\n \t}\n-\tsnprintf(temp, sizeof(temp), \"-%d\", pnum);\n-\tstrlcat(proppath, temp, proppath_size);\n+\tseq_buf_printf(\u0026s, \"-%d\", pnum);\n+\n+\tseq_buf_str(\u0026s);\n }\n \n /\ndiff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\nindex 0f242db775e1c..548a50f744224 100644\n--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\n+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\n@@ -4,6 +4,7 @@\n /\n \n #include \u003clinux/debugfs.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003cdrm/drm_print.h\u003e\n #include \u003cdrm/drm_debugfs.h\u003e\n@@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf,\n \tstruct xe_hw_engine hwe;\n \tenum xe_hw_engine_id id;\n \tchar engines[128];\n+\tstruct seq_buf s;\n+\tconst char s_str;\n \n-\tengines[0] = '\\0';\n+\tseq_buf_init(\u0026s, engines, sizeof(engines));\n \n \tif (group \u003c num_groups) {\n \t\tfor_each_hw_engine(hwe, gt, id) {\n@@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf,\n \t\t\tu16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe);\n \t\t\tu32 mask = groups[group].engines[guc_class];\n \n-\t\t\tif (mask \u0026 BIT(guc_logical_instance)) {\n-\t\t\t\tstrlcat(engines, hwe-\u003ename, sizeof(engines));\n-\t\t\t\tstrlcat(engines, \" \", sizeof(engines));\n-\t\t\t}\n+\t\t\tif (mask \u0026 BIT(guc_logical_instance))\n+\t\t\t\tseq_buf_printf(\u0026s, \"%s \", hwe-\u003ename);\n \t\t}\n-\t\tstrlcat(engines, \"\\n\", sizeof(engines));\n+\t\tseq_buf_puts(\u0026s, \"\\n\");\n \t}\n \n-\treturn simple_read_from_buffer(buf, count, ppos, engines, strlen(engines));\n+\ts_str = seq_buf_str(\u0026s);\n+\treturn simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));\n }\n \n static const struct file_operations sched_group_engines_fops = {\n@@ -663,15 +665,15 @@ static ssize_t control_write(struct file file, const char __user buf, size_t c\n static ssize_t control_read(struct file file, char __user buf, size_t count, loff_t ppos)\n {\n \tchar help[128];\n+\tstruct seq_buf s;\n \tsize_t n;\n \n-\thelp[0] = '\\0';\n+\tseq_buf_init(\u0026s, help, sizeof(help));\n \tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\n-\t\tstrlcat(help, control_cmds[n].cmd, sizeof(help));\n-\t\tstrlcat(help, \"\\n\", sizeof(help));\n+\t\tseq_buf_printf(\u0026s, \"%s\\n\", control_cmds[n].cmd);\n \t}\n \n-\treturn simple_read_from_buffer(buf, count, ppos, help, strlen(help));\n+\treturn simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(\u0026s));\n }\n \n static const struct file_operations control_ops = {\ndiff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c\nindex 880a0c79148cd..d13d2d6202ee5 100644\n--- a/drivers/input/mouse/synaptics_usb.c\n+++ b/drivers/input/mouse/synaptics_usb.c\n@@ -41,6 +41,7 @@\n #include \u003clinux/usb.h\u003e\n #include \u003clinux/input.h\u003e\n #include \u003clinux/usb/input.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #define USB_VENDOR_ID_SYNAPTICS\t0x06cb\n #define USB_DEVICE_ID_SYNAPTICS_TP\t0x0001\t/ Synaptics USB TouchPad /\n@@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface intf,\n \tstruct input_dev input_dev;\n \tunsigned int intf_num = intf-\u003ecur_altsetting-\u003edesc.bInterfaceNumber;\n \tunsigned int altsetting = min(intf-\u003enum_altsetting, 1U);\n+\tstruct seq_buf s;\n+\tchar path[64];\n \tint error;\n \n \terror = usb_set_interface(udev, intf_num, altsetting);\n@@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface intf,\n \t\t\t ep-\u003ebInterval);\n \tsynusb-\u003eurb-\u003etransfer_flags \|= URB_NO_TRANSFER_DMA_MAP;\n \n+\tseq_buf_init(\u0026s, synusb-\u003ename, sizeof(synusb-\u003ename));\n+\n \tif (udev-\u003emanufacturer)\n-\t\tstrscpy(synusb-\u003ename, udev-\u003emanufacturer,\n-\t\t\tsizeof(synusb-\u003ename));\n+\t\tseq_buf_puts(\u0026s, udev-\u003emanufacturer);\n \n \tif (udev-\u003eproduct) {\n \t\tif (udev-\u003emanufacturer)\n-\t\t\tstrlcat(synusb-\u003ename, \" \", sizeof(synusb-\u003ename));\n-\t\tstrlcat(synusb-\u003ename, udev-\u003eproduct, sizeof(synusb-\u003ename));\n+\t\t\tseq_buf_puts(\u0026s, \" \");\n+\t\tseq_buf_puts(\u0026s, udev-\u003eproduct);\n \t}\n \n-\tif (!strlen(synusb-\u003ename))\n-\t\tsnprintf(synusb-\u003ename, sizeof(synusb-\u003ename),\n-\t\t\t \"USB Synaptics Device %04x:%04x\",\n-\t\t\t le16_to_cpu(udev-\u003edescriptor.idVendor),\n-\t\t\t le16_to_cpu(udev-\u003edescriptor.idProduct));\n+\tif (!seq_buf_used(\u0026s))\n+\t\tseq_buf_printf(\u0026s, \"USB Synaptics Device %04x:%04x\",\n+\t\t\t le16_to_cpu(udev-\u003edescriptor.idVendor),\n+\t\t\t le16_to_cpu(udev-\u003edescriptor.idProduct));\n \n \tif (synusb-\u003eflags \u0026 SYNUSB_STICK)\n-\t\tstrlcat(synusb-\u003ename, \" (Stick)\", sizeof(synusb-\u003ename));\n+\t\tseq_buf_puts(\u0026s, \" (Stick)\");\n+\n+\tseq_buf_str(\u0026s);\n \n-\tusb_make_path(udev, synusb-\u003ephys, sizeof(synusb-\u003ephys));\n-\tstrlcat(synusb-\u003ephys, \"/input0\", sizeof(synusb-\u003ephys));\n+\tusb_make_path(udev, path, sizeof(path));\n+\tsnprintf(synusb-\u003ephys, sizeof(synusb-\u003ephys), \"%s/input0\", path);\n \n \tinput_dev-\u003ename = synusb-\u003ename;\n \tinput_dev-\u003ephys = synusb-\u003ephys;\ndiff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c\nindex f1241b63aa5ce..bd15eb58fc84f 100644\n--- a/drivers/media/dvb-frontends/si2165.c\n+++ b/drivers/media/dvb-frontends/si2165.c\n@@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client client)\n \t\tchip_name, rev_char, state-\u003echip_type,\n \t\tstate-\u003echip_revcode);\n \n-\tstrlcat(state-\u003efe.ops.info.name, chip_name,\n-\t\tsizeof(state-\u003efe.ops.info.name));\n+\tsnprintf(state-\u003efe.ops.info.name, sizeof(state-\u003efe.ops.info.name),\n+\t\t \"Silicon Labs %s%s%s\",\n+\t\t chip_name,\n+\t\t state-\u003ehas_dvbt ? \" DVB-T\" : \"\",\n+\t\t state-\u003ehas_dvbc ? \" DVB-C\" : \"\");\n \n \tn = 0;\n-\tif (state-\u003ehas_dvbt) {\n+\tif (state-\u003ehas_dvbt)\n \t\tstate-\u003efe.ops.delsys[n++] = SYS_DVBT;\n-\t\tstrlcat(state-\u003efe.ops.info.name, \" DVB-T\",\n-\t\t\tsizeof(state-\u003efe.ops.info.name));\n-\t}\n-\tif (state-\u003ehas_dvbc) {\n+\tif (state-\u003ehas_dvbc)\n \t\tstate-\u003efe.ops.delsys[n++] = SYS_DVBC_ANNEX_A;\n-\t\tstrlcat(state-\u003efe.ops.info.name, \" DVB-C\",\n-\t\t\tsizeof(state-\u003efe.ops.info.name));\n-\t}\n \n \t/ return fe pointer /\n \tpdata-\u003efe = \u0026state-\u003efe;\ndiff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h\nindex 1b6a8fbaa6485..9f792128a0efe 100644\n--- a/drivers/net/ethernet/intel/i40e/i40e.h\n+++ b/drivers/net/ethernet/intel/i40e/i40e.h\n@@ -1059,19 +1059,26 @@ static inline char i40e_nvm_version_str(struct i40e_hw hw, char buf,\n \t\t\t\t\t size_t len)\n {\n \tchar ver[16] = \" \";\n+\tsize_t offset;\n \n \t/ Get NVM version /\n \ti40e_info_nvm_ver(hw, buf, len);\n \n \t/ Append EETrackID if provided /\n \ti40e_info_eetrack(hw, \u0026ver[1], sizeof(ver) - 1);\n-\tif (strlen(ver) \u003e 1)\n-\t\tstrlcat(buf, ver, len);\n+\tif (strlen(ver) \u003e 1) {\n+\t\toffset = strlen(buf);\n+\t\tif (offset \u003c len)\n+\t\t\tsnprintf(buf + offset, len - offset, \"%s\", ver);\n+\t}\n \n \t/ Append combo image version if provided /\n \ti40e_info_civd_ver(hw, \u0026ver[1], sizeof(ver) - 1);\n-\tif (strlen(ver) \u003e 1)\n-\t\tstrlcat(buf, ver, len);\n+\tif (strlen(ver) \u003e 1) {\n+\t\toffset = strlen(buf);\n+\t\tif (offset \u003c len)\n+\t\t\tsnprintf(buf + offset, len - offset, \"%s\", ver);\n+\t}\n \n \treturn buf;\n }\ndiff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c\nindex 479b2418ca340..fcc9e9eb57322 100644\n--- a/drivers/net/wireless/ath/wil6210/wmi.c\n+++ b/drivers/net/wireless/ath/wil6210/wmi.c\n@@ -7,6 +7,7 @@\n #include \u003clinux/moduleparam.h\u003e\n #include \u003clinux/etherdevice.h\u003e\n #include \u003clinux/if_arp.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \"wil6210.h\"\n #include \"txrx.h\"\n@@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv wil)\n \n static void resume_triggers2string(u32 triggers, char string, int str_size)\n {\n-\tstring[0] = '\\0';\n+\tstruct seq_buf s;\n+\n+\tseq_buf_init(\u0026s, string, str_size);\n \n \tif (!triggers) {\n-\t\tstrlcat(string, \" UNKNOWN\", str_size);\n-\t\treturn;\n-\t}\n+\t\tseq_buf_puts(\u0026s, \" UNKNOWN\");\n+\t} else {\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_HOST)\n+\t\t\tseq_buf_puts(\u0026s, \" HOST\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_HOST)\n-\t\tstrlcat(string, \" HOST\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_UCAST_RX)\n+\t\t\tseq_buf_puts(\u0026s, \" UCAST_RX\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_UCAST_RX)\n-\t\tstrlcat(string, \" UCAST_RX\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_BCAST_RX)\n+\t\t\tseq_buf_puts(\u0026s, \" BCAST_RX\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_BCAST_RX)\n-\t\tstrlcat(string, \" BCAST_RX\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_WMI_EVT)\n+\t\t\tseq_buf_puts(\u0026s, \" WMI_EVT\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_WMI_EVT)\n-\t\tstrlcat(string, \" WMI_EVT\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_DISCONNECT)\n+\t\t\tseq_buf_puts(\u0026s, \" DISCONNECT\");\n+\t}\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_DISCONNECT)\n-\t\tstrlcat(string, \" DISCONNECT\", str_size);\n+\tseq_buf_str(\u0026s);\n }\n \n int wmi_resume(struct wil6210_priv wil)\ndiff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\nindex 22ff326f1924a..2f74a952599ec 100644\n--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\n+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\n@@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev,\n \tfwreq-\u003en_items = n_fwnames;\n \n \tfor (j = 0; j \u003c n_fwnames; j++) {\n-\t\tfwreq-\u003eitems[j].path = fwnames[j].path;\n-\t\tfwnames[j].path[0] = '\\0';\n \t\t/* check if firmware path is provided by module parameter /\n \t\tif (brcmf_mp_global.firmware_path[0] != '\\0') {\n-\t\t\tstrscpy(fwnames[j].path, mp_path,\n-\t\t\t\tBRCMF_FW_NAME_LEN);\n-\n-\t\t\tif (end != '/') {\n-\t\t\t\tstrlcat(fwnames[j].path, \"/\",\n-\t\t\t\t\tBRCMF_FW_NAME_LEN);\n-\t\t\t}\n+\t\t\tsnprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, \"%s%s%s%s\",\n+\t\t\t\t mp_path, (end == '/') ? \"\" : \"/\",\n+\t\t\t\t mapping_table[i].fw_base,\n+\t\t\t\t fwnames[j].extension);\n+\t\t} else {\n+\t\t\tsnprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, \"%s%s\",\n+\t\t\t\t mapping_table[i].fw_base,\n+\t\t\t\t fwnames[j].extension);\n \t\t}\n-\t\tstrlcat(fwnames[j].path, mapping_table[i].fw_base,\n-\t\t\tBRCMF_FW_NAME_LEN);\n-\t\tstrlcat(fwnames[j].path, fwnames[j].extension,\n-\t\t\tBRCMF_FW_NAME_LEN);\n \t\tfwreq-\u003eitems[j].path = fwnames[j].path;\n \t}\n \ndiff --git a/drivers/of/fdt.c b/drivers/of/fdt.c\nindex a64afc3ded3d4..311021a83f03e 100644\n--- a/drivers/of/fdt.c\n+++ b/drivers/of/fdt.c\n@@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char cmdline)\n \tconst void rng_seed;\n \tconst void fdt = initial_boot_params;\n \n+\tif (!fdt)\n+\t\tgoto handle_cmdline;\n+\n \tnode = fdt_path_offset(fdt, \"/chosen\");\n \tif (node \u003c 0)\n \t\tnode = fdt_path_offset(fdt, \"/chosen@0\");\n@@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char cmdline)\n \t /\n #ifdef CONFIG_CMDLINE\n #if defined(CONFIG_CMDLINE_EXTEND)\n-\tstrlcat(cmdline, \" \", COMMAND_LINE_SIZE);\n-\tstrlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n+\t{\n+\t\tsize_t len = strlen(cmdline);\n+\n+\t\tif (len \u003c COMMAND_LINE_SIZE)\n+\t\t\tsnprintf(cmdline + len, COMMAND_LINE_SIZE - len, \" %s\", CONFIG_CMDLINE);\n+\t}\n #elif defined(CONFIG_CMDLINE_FORCE)\n \tstrscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n #else\ndiff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c\nindex 5ecc9ed4c44db..0d639eec689c0 100644\n--- a/drivers/pinctrl/samsung/pinctrl-samsung.c\n+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c\n@@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device dev, struct samsung_pinctrl_dr\n \n \tbank = d-\u003epin_banks;\n \tfor (i = 0; i \u003c d-\u003enr_banks; ++i, ++bank) {\n-\t\tstrscpy(node_name, bank-\u003ename, sizeof(node_name));\n-\t\tlen = strlcat(node_name, suffix, sizeof(node_name));\n+\t\tlen = snprintf(node_name, sizeof(node_name), \"%s%s\", bank-\u003ename, suffix);\n \t\tif (len \u003e= sizeof(node_name)) {\n \t\t\tdev_err(dev, \"Too long pin bank name '%s', ignoring\\n\",\n \t\t\t\tbank-\u003ename);\ndiff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c\nindex 9b57312f43f50..9fe0343c0b321 100644\n--- a/drivers/scsi/bfa/bfa_fcs.c\n+++ b/drivers/scsi/bfa/bfa_fcs.c\n@@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s fabric)\n \n \tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n \n-\t/* Model name/number /\n-\tstrscpy(port_cfg-\u003esym_name.symname, model,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/ Driver Version /\n-\tstrlcat(port_cfg-\u003esym_name.symname, driver_info-\u003eversion,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/ Host machine name /\n-\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\tdriver_info-\u003ehost_machine_name,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n \t/\n \t * Host OS Info :\n \t * If OS Patch Info is not there, do not truncate any bytes from the\n \t * OS name string and instead copy the entire OS info string (64 bytes).\n \t /\n \tif (driver_info-\u003ehost_os_patch[0] == '\\0') {\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_name,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n+\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t\t \"%s%s%s%s%s%s%s%s\",\n+\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);\n \t} else {\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_name,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t\t/ Append host OS Patch Info /\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_patch,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n+\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t\t \"%s%s%s%s%s%s%s%s%s\",\n+\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_patch);\n \t}\n \n \t/ null terminate /\n@@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s fabric)\n \n \tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n \n-\t/* Model name/number /\n-\tstrscpy(port_cfg-\u003enode_sym_name.symname, model,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/ Driver Version /\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname, (char )driver_info-\u003eversion,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* Host machine name /\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\tdriver_info-\u003ehost_machine_name,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/ null terminate /\n-\tport_cfg-\u003enode_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;\n+\t/ Model name/number, Driver Version, Host machine name /\n+\tsnprintf(port_cfg-\u003enode_sym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t model, (char )driver_info-\u003eversion,\n+\t\t driver_info-\u003ehost_machine_name);\n }\n \n /\ndiff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c\nindex 432612d224374..a28208414aec2 100644\n--- a/fs/nfs/nfsroot.c\n+++ b/fs/nfs/nfsroot.c\n@@ -173,12 +173,15 @@ static int __init root_nfs_cat(char dest, const char src,\n \t\t\t const size_t destlen)\n {\n \tsize_t len = strlen(dest);\n+\tint ret;\n \n-\tif (len \u0026\u0026 dest[len - 1] != ',')\n-\t\tif (strlcat(dest, \",\", destlen) \u003e= destlen)\n-\t\t\treturn -1;\n+\tif (len \u003e= destlen)\n+\t\treturn -1;\n+\n+\tret = snprintf(dest + len, destlen - len, \"%s%s\",\n+\t\t (len \u0026\u0026 dest[len - 1] != ',') ? \",\" : \"\", src);\n \n-\tif (strlcat(dest, src, destlen) \u003e= destlen)\n+\tif (ret \u003c 0 \|\| ret \u003e= destlen - len)\n \t\treturn -1;\n \treturn 0;\n }\ndiff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c\nindex 9f94919a6bc62..6e2f9887eab4b 100644\n--- a/fs/orangefs/orangefs-debugfs.c\n+++ b/fs/orangefs/orangefs-debugfs.c\n@@ -37,6 +37,7 @@\n /\n #include \u003clinux/debugfs.h\u003e\n #include \u003clinux/slab.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003clinux/uaccess.h\u003e\n \n@@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \tchar client_title = \"Client Debug Keywords:\\n\";\n \tchar kernel_title = \"Kernel Debug Keywords:\\n\";\n \tsize_t string_size = DEBUG_HELP_STRING_SIZE;\n-\tsize_t result_size;\n \tsize_t i;\n \tchar new;\n \tint rc = -EINVAL;\n+\tstruct seq_buf s;\n \n \tgossip_debug(GOSSIP_UTILS_DEBUG, \"%s: start\\n\", __func__);\n \n@@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t\tgoto out;\n \t}\n \n+\tseq_buf_init(\u0026s, new, string_size);\n+\n \t/\n-\t * strlcat(dst, src, size) will append at most\n-\t * \"size - strlen(dst) - 1\" bytes of src onto dst,\n-\t * null terminating the result, and return the total\n-\t * length of the string it tried to create.\n-\t \n \t We'll just plow through here building our new debug\n-\t * help string and let strlcat take care of assuring that\n+\t * help string and let seq_buf take care of assuring that\n \t * dst doesn't overflow.\n \t /\n-\tstrlcat(new, client_title, string_size);\n+\tseq_buf_puts(\u0026s, client_title);\n \n \tif (!at_boot) {\n \n@@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t\t\tgoto out;\n \t\t}\n \n-\t\tfor (i = 0; i \u003c cdm_element_count; i++) {\n-\t\t\tstrlcat(new, \"\\t\", string_size);\n-\t\t\tstrlcat(new, cdm_array[i].keyword, string_size);\n-\t\t\tstrlcat(new, \"\\n\", string_size);\n-\t\t}\n+\t\tfor (i = 0; i \u003c cdm_element_count; i++)\n+\t\t\tseq_buf_printf(\u0026s, \"\\t%s\\n\", cdm_array[i].keyword);\n \t}\n \n-\tstrlcat(new, \"\\n\", string_size);\n-\tstrlcat(new, kernel_title, string_size);\n+\tseq_buf_puts(\u0026s, \"\\n\");\n+\tseq_buf_puts(\u0026s, kernel_title);\n \n-\tfor (i = 0; i \u003c num_kmod_keyword_mask_map; i++) {\n-\t\tstrlcat(new, \"\\t\", string_size);\n-\t\tstrlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size);\n-\t\tresult_size = strlcat(new, \"\\n\", string_size);\n-\t}\n+\tfor (i = 0; i \u003c num_kmod_keyword_mask_map; i++)\n+\t\tseq_buf_printf(\u0026s, \"\\t%s\\n\", s_kmod_keyword_mask_map[i].keyword);\n \n \t/ See if we tried to put too many bytes into \"new\"... /\n-\tif (result_size \u003e= string_size) {\n+\tif (seq_buf_has_overflowed(\u0026s)) {\n \t\tkfree(new);\n \t\tgoto out;\n \t}\n@@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t} else {\n \t\tmutex_lock(\u0026orangefs_help_file_lock);\n \t\tmemset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE);\n-\t\tstrlcat(debug_help_string, new, string_size);\n+\t\tstrscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE);\n \t\tmutex_unlock(\u0026orangefs_help_file_lock);\n \t\tkfree(new);\n \t}\ndiff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h\nindex cf841dc71feff..0b489124bfcb8 100644\n--- a/include/linux/fortify-string.h\n+++ b/include/linux/fortify-string.h\n@@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)\n char strcat(char * const POS p, const char q)\n {\n \tconst size_t p_size = __member_size(p);\n-\tconst size_t wanted = strlcat(p, q, p_size);\n+\n+\tif (p_size == SIZE_MAX)\n+\t\treturn __underlying_strcat(p, q);\n+\n+\tconst size_t p_len = __fortify_strlen(p);\n+\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n \n \tif (p_size \u003c= wanted)\n \t\tfortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);\ndiff --git a/net/devlink/dev.c b/net/devlink/dev.c\nindex 55959b0ff5ab4..987b071345c41 100644\n--- a/net/devlink/dev.c\n+++ b/net/devlink/dev.c\n@@ -5,6 +5,7 @@\n /\n \n #include \u003clinux/device.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003cnet/genetlink.h\u003e\n #include \u003cnet/sock.h\u003e\n #include \"devl_internal.h\"\n@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink devlink,\n {\n \tstruct devlink_info_req req = {};\n \tconst struct nlattr nlattr;\n+\tstruct seq_buf s;\n \tstruct sk_buff msg;\n \tint rem, err;\n \n@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink devlink,\n \tif (err)\n \t\tgoto free_msg;\n \n+\tseq_buf_init(\u0026s, buf, len);\n+\ts.len = strnlen(buf, len);\n+\n \tnla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,\n \t\t\t (void )msg-\u003edata, msg-\u003elen, rem) {\n \t\tconst struct nlattr kv;\n@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink devlink,\n \n \t\tnla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,\n \t\t\t\t\t nlattr, rem_kv) {\n-\t\t\tstrlcat(buf, nla_data(kv), len);\n-\t\t\tstrlcat(buf, \" \", len);\n+\t\t\tseq_buf_printf(\u0026s, \"%s \", (const char )nla_data(kv));\n \t\t}\n \t}\n free_msg:\ndiff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c\nindex 97ff11973c493..a1e4173e5a538 100644\n--- a/net/sunrpc/addr.c\n+++ b/net/sunrpc/addr.c\n@@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton);\n /\n char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags)\n {\n-\tchar portbuf[RPCBIND_MAXUADDRPLEN];\n \tchar addrbuf[RPCBIND_MAXUADDRLEN];\n \tunsigned short port;\n+\tsize_t len;\n \n \tswitch (sap-\u003esa_family) {\n \tcase AF_INET:\n-\t\tif (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)\n+\t\tlen = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));\n+\t\tif (len == 0 \|\| len \u003e= sizeof(addrbuf))\n \t\t\treturn NULL;\n \t\tport = ntohs(((struct sockaddr_in )sap)-\u003esin_port);\n \t\tbreak;\n \tcase AF_INET6:\n-\t\tif (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)\n+\t\tlen = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf));\n+\t\tif (len == 0 \|\| len \u003e= sizeof(addrbuf))\n \t\t\treturn NULL;\n \t\tport = ntohs(((struct sockaddr_in6 )sap)-\u003esin6_port);\n \t\tbreak;\n@@ -283,11 +285,8 @@ char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags)\n \t\treturn NULL;\n \t}\n \n-\tif (snprintf(portbuf, sizeof(portbuf),\n-\t\t \".%u.%u\", port \u003e\u003e 8, port \u0026 0xff) \u003e= (int)sizeof(portbuf))\n-\t\treturn NULL;\n-\n-\tif (strlcat(addrbuf, portbuf, sizeof(addrbuf)) \u003e= sizeof(addrbuf))\n+\tif (snprintf(addrbuf + len, sizeof(addrbuf) - len,\n+\t\t \".%u.%u\", port \u003e\u003e 8, port \u0026 0xff) \u003e= sizeof(addrbuf) - len)\n \t\treturn NULL;\n \n \treturn kstrdup(addrbuf, gfp_flags);\n@@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net net, const char uaddr,\n \treturn 0;\n }\n EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);\n+\ndiff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c\nindex 0bb65be021d97..e145099ee02a9 100644\n--- a/sound/pci/ac97/ac97_codec.c\n+++ b/sound/pci/ac97/ac97_codec.c\n@@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name,\n \n \tpid = look_for_codec_id(snd_ac97_codec_ids, id);\n \tif (pid) {\n-\t\tstrlcat(name, \" \", maxlen);\n-\t\tstrlcat(name, pid-\u003ename, maxlen);\n+\t\tint l = strlen(name);\n+\n \t\tif (pid-\u003emask != 0xffffffff)\n-\t\t\tsprintf(name + strlen(name), \" rev %u\", id \u0026 ~pid-\u003emask);\n+\t\t\tsnprintf(name + l, maxlen - l, \" %s rev %u\", pid-\u003ename, id \u0026 ~pid-\u003emask);\n+\t\telse\n+\t\t\tsnprintf(name + l, maxlen - l, \" %s\", pid-\u003ename);\n \t\tif (ac97 \u0026\u0026 pid-\u003epatch) {\n \t\t\tif ((modem \u0026\u0026 (pid-\u003eflags \u0026 AC97_MODEM_PATCH)) \|\|\n \t\t\t (! modem \u0026\u0026 ! (pid-\u003eflags \u0026 AC97_MODEM_PATCH)))\n@@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name,\n \t\t}\n \t} else {\n \t\tint l = strlen(name);\n+\n \t\tsnprintf(name + l, maxlen - l, \" id %x\", id \u0026 0xff);\n \t}\n }\ndiff --git a/sound/usb/card.c b/sound/usb/card.c\nindex 9307da95efbef..bdca8085fca66 100644\n--- a/sound/usb/card.c\n+++ b/sound/usb/card.c\n@@ -25,6 +25,7 @@\n #include \u003clinux/list.h\u003e\n #include \u003clinux/slab.h\u003e\n #include \u003clinux/string.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/ctype.h\u003e\n #include \u003clinux/usb.h\u003e\n #include \u003clinux/moduleparam.h\u003e\n@@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device dev,\n \tstruct snd_card card = chip-\u003ecard;\n \tconst struct usb_audio_device_name preset;\n \tconst char s = NULL;\n-\tint len;\n+\tstruct seq_buf sb;\n+\tchar buf;\n+\tsize_t size;\n \n \tpreset = lookup_device_name(chip-\u003eusb_id);\n \n@@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device dev,\n \t\ts = preset-\u003evendor_name;\n \telse if (quirk \u0026\u0026 quirk-\u003evendor_name)\n \t\ts = quirk-\u003evendor_name;\n-\tcard-\u003elongname = 0;\n+\n+\tseq_buf_init(\u0026sb, card-\u003elongname, sizeof(card-\u003elongname));\n+\n \tif (s \u0026\u0026 s)\n-\t\tstrscpy(card-\u003elongname, s);\n+\t\tseq_buf_puts(\u0026sb, s);\n \telse if (dev-\u003emanufacturer \u0026\u0026 dev-\u003emanufacturer)\n-\t\tstrscpy(card-\u003elongname, dev-\u003emanufacturer);\n-\n-\tif (card-\u003elongname) {\n-\t\tstrim(card-\u003elongname);\n-\t\tif (card-\u003elongname)\n-\t\t\tstrlcat(card-\u003elongname, \" \", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, dev-\u003emanufacturer);\n+\n+\tif (seq_buf_used(\u0026sb)) {\n+\t\tchar trimmed;\n+\n+\t\tseq_buf_str(\u0026sb);\n+\t\ttrimmed = strim(card-\u003elongname);\n+\t\tif (trimmed != card-\u003elongname)\n+\t\t\tmemmove(card-\u003elongname, trimmed, strlen(trimmed) + 1);\n+\t\tsb.len = strlen(card-\u003elongname);\n+\t\tif (sb.len)\n+\t\t\tseq_buf_putc(\u0026sb, ' ');\n \t}\n \n-\tstrlcat(card-\u003elongname, card-\u003eshortname, sizeof(card-\u003elongname));\n+\tseq_buf_puts(\u0026sb, card-\u003eshortname);\n \n-\tlen = strlcat(card-\u003elongname, \" at \", sizeof(card-\u003elongname));\n+\tseq_buf_puts(\u0026sb, \" at \");\n \n-\tif (len \u003c sizeof(card-\u003elongname))\n-\t\tusb_make_path(dev, card-\u003elongname + len, sizeof(card-\u003elongname) - len);\n+\tsize = seq_buf_get_buf(\u0026sb, \u0026buf);\n+\tif (size \u003e 0) {\n+\t\tint path_len = usb_make_path(dev, buf, size);\n+\n+\t\tif (path_len \u003e= 0)\n+\t\t\tseq_buf_commit(\u0026sb, path_len);\n+\t\telse\n+\t\t\tseq_buf_set_overflow(\u0026sb);\n+\t}\n \n \tswitch (snd_usb_get_speed(dev)) {\n \tcase USB_SPEED_LOW:\n-\t\tstrlcat(card-\u003elongname, \", low speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", low speed\");\n \t\tbreak;\n \tcase USB_SPEED_FULL:\n-\t\tstrlcat(card-\u003elongname, \", full speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", full speed\");\n \t\tbreak;\n \tcase USB_SPEED_HIGH:\n-\t\tstrlcat(card-\u003elongname, \", high speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", high speed\");\n \t\tbreak;\n \tcase USB_SPEED_SUPER:\n-\t\tstrlcat(card-\u003elongname, \", super speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", super speed\");\n \t\tbreak;\n \tcase USB_SPEED_SUPER_PLUS:\n-\t\tstrlcat(card-\u003elongname, \", super speed plus\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", super speed plus\");\n \t\tbreak;\n \tdefault:\n \t\tbreak;\n \t}\n+\n+\tseq_buf_str(\u0026sb);\n }\n \n static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio chip)\ndiff --git a/sound/usb/mixer.c b/sound/usb/mixer.c\nindex ecaa8bc08d7ca..f64ecad4e77ea 100644\n--- a/sound/usb/mixer.c\n+++ b/sound/usb/mixer.c\n@@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new snd_usb_feature_unit_ctl = \u0026usb_feature_unit_ctl;\n /\n static size_t append_ctl_name(struct snd_kcontrol kctl, const char str)\n {\n-\treturn strlcat(kctl-\u003eid.name, str, sizeof(kctl-\u003eid.name));\n+\tsize_t len = strlen(kctl-\u003eid.name);\n+\n+\tif (len \u003e= sizeof(kctl-\u003eid.name))\n+\t\treturn len + strlen(str);\n+\treturn len + snprintf(kctl-\u003eid.name + len, sizeof(kctl-\u003eid.name) - len, \"%s\", str);\n }\n \n /\n@@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface mixer,\n \t}\n \n \tif (check_mapped_name(map, kctl-\u003eid.name, sizeof(kctl-\u003eid.name)))\n-\t\tstrlcat(kctl-\u003eid.name, \" Jack\", sizeof(kctl-\u003eid.name));\n+\t\tappend_ctl_name(kctl, \" Jack\");\n \telse\n \t\tget_connector_control_name(mixer, term, is_input, kctl-\u003eid.name,\n \t\t\t\t\t sizeof(kctl-\u003eid.name));\n" }
2/1	2026/09/15 11:08	agent	patch-evaluator	4m Model: core Args: null Results: { "EnableConfigs": [ "SND_USB_AUDIO", "MOUSE_SYNAPTICS_USB", "SUNRPC", "COMEDI_BOND", "COMEDI_MISC_DRIVERS", "COMEDI", "FORTIFY_SOURCE" ], "FocusSymbols": [ "usb_audio_make_longname", "snd_usb_audio_create", "build_connector_control", "synusb_probe", "rpc_sockaddr2uaddr", "devlink_compat_running_version", "bonding_attach" ], "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer and security engineer. Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on internal assumptions. You must actively use your code access tools to inspect the actual source code, callers, and surrounding context. ================================================================================ 1. CORE TRIAGE PHILOSOPHY ================================================================================ The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs, and newly triggered assertions introduced by the patch series. - REACHABILITY IS THE PRIMARY GATE: Fuzzing can only discover bugs in code that can actually execute in standard virtualized environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap). If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed, regardless of whether it adds assertions or complex logic. - DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS: Patch authors routinely label changes as "cleanups", "refactorings", or state "No functional change intended". Do NOT take these claims at face value. Code refactorings that rearrange logic, introduce helper functions, or alter state management in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs. If reachable executable code is modified or refactored, it MUST be fuzzed. - NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED: When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON, VM_WARN_ON, BUG_ON, lockdep_assert) in reachable code paths, it enforces new or stricter invariants. Even if the author believes the invariant always holds, fuzzing is essential to verify whether an unusual sequence of operations can violate it. ================================================================================ 2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA) ================================================================================ Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories: - Non-kernel and non-executable changes: * Modifications to Documentation/, comments, or spelling fixes. * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/) that do not affect the compiled kernel image (vmlinux) or kernel modules. * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures. * Build system or Kconfig changes that do not alter compiled C logic. - Structurally unreachable hardware: * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU. - Unreachable execution paths: * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during physical PCI hot-unplug or manual sysfs driver unbinding. * Code paths exclusive to architectures other than the target architecture. ================================================================================ 3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA) ================================================================================ Return WorthFuzzing=true whenever the patch touches reachable executable code, including: - Core Subsystems: * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/), BPF, scheduler, core networking, VFS, or syscall handling. - Refactorings and Code Cleanups: * Any restructuring of reachable data structures, helper abstractions, or algorithm flows. - Runtime Assertions and Defensive Checks: * Any introduction or alteration of assertions (WARN_ON, VM_WARN_ON, BUG_ON, etc.) in reachable paths. - Reachable Drivers and Protocols: Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.). ================================================================================ 4. EXTRACTING FocusSymbols (PREVENTING DILUTION) ================================================================================ When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer: - AVOID UBIQUITOUS LIFECYCLE HOT-PATHS: Do NOT list generic, ubiquitous functions called by almost every program in the corpus (including, but not limited to: general memory allocators and deallocators, page fault and trap handlers, or core synchronization primitives; this is not an exhaustive list). Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused", which severely dilutes fuzzing effort away from the actual changes. - TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS: List functions that specifically implement the logic being added or altered, or direct API entrypoints for the subsystem feature under review. - HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers). ================================================================================ 5. IDENTIFYING EnableConfigs ================================================================================ Identify any specific CONFIG_ options required to properly compile and reach the modified code: - Inspect Kconfig files and #ifdef guards; do not make assumptions. - Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed. - Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 7af038477662f04c34c484a45e1a571280e5f258 Author: syz-cluster <triage@syzkaller.com> Date: Tue Sep 15 11:08:01 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c index 4ec591bde3dfa..21140b44d96e6 100644 --- a/arch/arm/kernel/atags_parse.c +++ b/arch/arm/kernel/atags_parse.c @@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision); static int __init parse_tag_cmdline(const struct tag tag) { #if defined(CONFIG_CMDLINE_EXTEND) - strlcat(default_command_line, " ", COMMAND_LINE_SIZE); - strlcat(default_command_line, tag->u.cmdline.cmdline, - COMMAND_LINE_SIZE); + size_t len = strlen(default_command_line); + + snprintf(default_command_line + len, COMMAND_LINE_SIZE - len, + " %s", tag->u.cmdline.cmdline); #elif defined(CONFIG_CMDLINE_FORCE) pr_warn("Ignoring tag cmdline (using the default kernel command line)\n"); #else diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c index 6fa4a22a58fd6..826396f141b9c 100644 --- a/arch/loongarch/kernel/setup.c +++ b/arch/loongarch/kernel/setup.c @@ -33,6 +33,7 @@ #include <linux/of_address.h> #include <linux/suspend.h> #include <linux/swiotlb.h> +#include <linux/seq_buf.h> #include <asm/addrspace.h> #include <asm/alternative.h> @@ -305,6 +306,8 @@ static void __init fdt_setup(void) static void __init bootcmdline_init(char cmdline_p) { + struct seq_buf s; + / * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line * is trivial - we simply use the built-in command line unconditionally & @@ -315,6 +318,11 @@ static void __init bootcmdline_init(char *cmdline_p) goto out; } + / Initialize seq_buf pointing to boot_command_line / + s.buffer = boot_command_line; + s.size = COMMAND_LINE_SIZE; + s.len = strlen(boot_command_line); + #ifdef CONFIG_OF_FLATTREE / * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system, @@ -323,11 +331,11 @@ static void __init bootcmdline_init(char *cmdline_p) to boot_command_line. / if (initial_boot_params) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + if (s.len) + seq_buf_puts(&s, " "); - if (!strstr(boot_command_line, init_command_line)) - strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE); + if (!strstr(s.buffer, init_command_line)) + seq_buf_puts(&s, init_command_line); goto out; } @@ -338,14 +346,14 @@ static void __init bootcmdline_init(char cmdline_p) CONFIG_CMDLINE_EXTEND is enabled. / if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) && CONFIG_CMDLINE[0]) { - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + seq_buf_puts(&s, " "); + seq_buf_puts(&s, CONFIG_CMDLINE); } / * Use built-in command line if the bootloader command line is empty. / - if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !boot_command_line[0]) + if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !s.len) strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); out: diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 1ae6d0c0e1d67..0d9c2137d6758 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void) static void __init bootcmdline_append(const char s, size_t max) { + size_t len; + int prec; + if (!s[0] \|\| !max) return; - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + len = strlen(boot_command_line); + if (len >= COMMAND_LINE_SIZE - 1) + return; - strlcat(boot_command_line, s, max); + if (len) { + if (COMMAND_LINE_SIZE - len < 3) + return; + + prec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2); + snprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, " %.s", + prec, s); + } else { + prec = min_t(size_t, max, COMMAND_LINE_SIZE - 1); + snprintf(boot_command_line, COMMAND_LINE_SIZE, "%.s", + prec, s); + } } #ifdef CONFIG_OF_EARLY_FLATTREE diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c index d3e17a7a89016..fa3efc82ad874 100644 --- a/arch/parisc/kernel/setup.c +++ b/arch/parisc/kernel/setup.c @@ -17,6 +17,7 @@ #include <linux/init.h> #include <linux/console.h> #include <linux/seq_file.h> +#include <linux/seq_buf.h> #define PCI_DEBUG #include <linux/pci.h> #undef PCI_DEBUG @@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE]; static void __init setup_cmdline(char *cmdline_p) { extern unsigned int boot_args[]; + struct seq_buf s; char p; cmdline_p = command_line; @@ -54,19 +56,21 @@ static void __init setup_cmdline(char cmdline_p) strscpy(boot_command_line, (char )__va(boot_args[1]), COMMAND_LINE_SIZE); + s.buffer = boot_command_line; + s.size = COMMAND_LINE_SIZE; + s.len = strlen(boot_command_line); + /* autodetect console type (if not done by palo yet) / p = boot_command_line; if (!str_has_prefix(p, "console=") && !strstr(p, " console=")) { - strlcat(p, " console=", COMMAND_LINE_SIZE); - if (PAGE0->mem_cons.cl_class == CL_DUPLEX) - strlcat(p, "ttyS0", COMMAND_LINE_SIZE); - else - strlcat(p, "tty0", COMMAND_LINE_SIZE); + seq_buf_printf(&s, " console=%s", + PAGE0->mem_cons.cl_class == CL_DUPLEX ? + "ttyS0" : "tty0"); } / default to use early console / if (!strstr(p, "earlycon")) - strlcat(p, " earlycon=pdc", COMMAND_LINE_SIZE); + seq_buf_printf(&s, " earlycon=pdc"); #ifdef CONFIG_BLK_DEV_INITRD / did palo pass us a ramdisk? / diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index cda6adb9f69c4..c40e0edd7c136 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -916,9 +916,11 @@ void __init setup_arch(char cmdline_p) #else if (builtin_cmdline[0]) { / append boot loader cmdline to builtin / - strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE); - strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE); - strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + char tmp[COMMAND_LINE_SIZE]; + + snprintf(tmp, COMMAND_LINE_SIZE, "%s %s", builtin_cmdline, boot_command_line); + strscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE); + strscpy(boot_command_line, tmp, COMMAND_LINE_SIZE); } #endif builtin_cmdline_added = true; diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c index 8e10ecab4f0dc..a10cfbd04c728 100644 --- a/drivers/comedi/drivers/comedi_bond.c +++ b/drivers/comedi/drivers/comedi_bond.c @@ -39,6 +39,7 @@ #include <linux/module.h> #include <linux/string.h> +#include <linux/seq_buf.h> #include <linux/slab.h> #include <linux/comedi.h> #include <linux/comedi/comedilib.h> @@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) { struct comedi_bond_private devpriv = dev->private; DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS); + struct seq_buf s; int i; memset(&devs_opened, 0, sizeof(devs_opened)); - devpriv->name[0] = 0; + seq_buf_init(&s, devpriv->name, sizeof(devpriv->name)); /* * Loop through all comedi devices specified on the command-line, * building our device list. @@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) } devpriv->devs = devs; devpriv->devs[devpriv->ndevs++] = bdev; - { - /* Append dev:subdev to devpriv->name / - char buf[20]; - - snprintf(buf, sizeof(buf), "%u:%u ", - bdev->minor, bdev->subdev); - strlcat(devpriv->name, buf, - sizeof(devpriv->name)); - } + + / Append dev:subdev to devpriv->name / + seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev); } } @@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) return -EINVAL; } + seq_buf_str(&s); + return 0; } diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c index 9c0a1e48f96f2..4e3781815b6d7 100644 --- a/drivers/edac/thunderx_edac.c +++ b/drivers/edac/thunderx_edac.c @@ -20,6 +20,7 @@ #include <linux/atomic.h> #include <linux/bitfield.h> #include <linux/circ_buf.h> +#include <linux/seq_buf.h> #include <asm/page.h> @@ -47,12 +48,17 @@ static void decode_register(char str, size_t size, { int ret = 0; + if (size > 0) + str[0] = '\0'; + while (descr->type && descr->mask && descr->descr) { if (reg & descr->mask) { ret = snprintf(str, size, "\n\t%s, %s", descr->type == ERR_CORRECTED ? "Corrected" : "Uncorrected", descr->descr); + if (ret < 0 \|\| ret >= size) + break; str += ret; size -= ret; } @@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void irq_id) while (CIRC_CNT(ocx->com_ring_head, ocx->com_ring_tail, ARRAY_SIZE(ocx->com_err_ctx))) { + struct seq_buf s; + tail = ring_pos(ocx->com_ring_tail, ARRAY_SIZE(ocx->com_err_ctx)); ctx = &ocx->com_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx", - ocx->edac_dev->ctl_name, ctx->reg_com_int); + seq_buf_init(&s, msg, OCX_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx", + ocx->edac_dev->ctl_name, ctx->reg_com_int); decode_register(other, OCX_OTHER_SIZE, ocx_com_errors, ctx->reg_com_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); for (lane = 0; lane < OCX_RX_LANES; lane++) if (ctx->reg_com_int & BIT(lane)) { - snprintf(other, OCX_OTHER_SIZE, - "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx", - lane, ctx->reg_lane_int[lane], - lane, ctx->reg_lane_stat11[lane]); - - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_printf(&s, + "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx", + lane, ctx->reg_lane_int[lane], + lane, ctx->reg_lane_stat11[lane]); decode_register(other, OCX_OTHER_SIZE, ocx_lane_errors, ctx->reg_lane_int[lane]); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); } if (ctx->reg_com_int & OCX_COM_INT_CE) - edac_device_handle_ce(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s)); ocx->com_ring_tail++; } @@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void irq_id) while (CIRC_CNT(ocx->link_ring_head, ocx->link_ring_tail, ARRAY_SIZE(ocx->link_err_ctx))) { + struct seq_buf s; + tail = ring_pos(ocx->link_ring_head, ARRAY_SIZE(ocx->link_err_ctx)); ctx = &ocx->link_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, - "%s: OCX_COM_LINK_INT[%d]: %016llx", - ocx->edac_dev->ctl_name, - ctx->link, ctx->reg_com_link_int); + seq_buf_init(&s, msg, OCX_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: OCX_COM_LINK_INT[%d]: %016llx", + ocx->edac_dev->ctl_name, + ctx->link, ctx->reg_com_link_int); decode_register(other, OCX_OTHER_SIZE, ocx_com_link_errors, ctx->reg_com_link_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); if (ctx->reg_com_link_int & OCX_COM_LINK_INT_UE) - edac_device_handle_ue(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ue(ocx->edac_dev, 0, 0, seq_buf_str(&s)); else if (ctx->reg_com_link_int & OCX_COM_LINK_INT_CE) - edac_device_handle_ce(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s)); ocx->link_ring_tail++; } @@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void irq_id) while (CIRC_CNT(l2c->ring_head, l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx))) { - snprintf(msg, L2C_MESSAGE_SIZE, - "%s: %s: %016llx, %s: %016llx", - l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, - ctx->reg_ext_name, ctx->reg_ext); + struct seq_buf s; + + tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx)); + ctx = &l2c->err_ctx[tail]; + + seq_buf_init(&s, msg, L2C_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: %s: %016llx, %s: %016llx", + l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, + ctx->reg_ext_name, ctx->reg_ext); decode_register(other, L2C_OTHER_SIZE, l2_errors, ctx->reg_int); - strlcat(msg, other, L2C_MESSAGE_SIZE); + seq_buf_puts(&s, other); if (ctx->reg_int & mask_ue) - edac_device_handle_ue(l2c->edac_dev, 0, 0, msg); + edac_device_handle_ue(l2c->edac_dev, 0, 0, seq_buf_str(&s)); else if (ctx->reg_int & mask_ce) - edac_device_handle_ce(l2c->edac_dev, 0, 0, msg); + edac_device_handle_ce(l2c->edac_dev, 0, 0, seq_buf_str(&s)); l2c->ring_tail++; } diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 7ce9e212770ad..229b5fec44bff 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -29,6 +29,7 @@ #include <linux/kernel.h> #include <linux/random.h> #include <linux/sched.h> +#include <linux/seq_buf.h> #include <linux/seq_file.h> #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) @@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch mstb, char proppath, size_t proppath_size) { + struct seq_buf s; int i; - char temp[8]; - snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id); + seq_buf_init(&s, proppath, proppath_size); + + seq_buf_printf(&s, "mst:%d", mstb->mgr->conn_base_id); for (i = 0; i < (mstb->lct - 1); i++) { int shift = (i % 2) ? 0 : 4; int port_num = (mstb->rad[i / 2] >> shift) & 0xf; - snprintf(temp, sizeof(temp), "-%d", port_num); - strlcat(proppath, temp, proppath_size); + seq_buf_printf(&s, "-%d", port_num); } - snprintf(temp, sizeof(temp), "-%d", pnum); - strlcat(proppath, temp, proppath_size); + seq_buf_printf(&s, "-%d", pnum); + + seq_buf_str(&s); } /* diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c index 0f242db775e1c..548a50f744224 100644 --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c @@ -4,6 +4,7 @@ / #include <linux/debugfs.h> +#include <linux/seq_buf.h> #include <drm/drm_print.h> #include <drm/drm_debugfs.h> @@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf, struct xe_hw_engine hwe; enum xe_hw_engine_id id; char engines[128]; + struct seq_buf s; + const char s_str; - engines[0] = '\0'; + seq_buf_init(&s, engines, sizeof(engines)); if (group < num_groups) { for_each_hw_engine(hwe, gt, id) { @@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf, u16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe); u32 mask = groups[group].engines[guc_class]; - if (mask & BIT(guc_logical_instance)) { - strlcat(engines, hwe->name, sizeof(engines)); - strlcat(engines, " ", sizeof(engines)); - } + if (mask & BIT(guc_logical_instance)) + seq_buf_printf(&s, "%s ", hwe->name); } - strlcat(engines, "\n", sizeof(engines)); + seq_buf_puts(&s, "\n"); } - return simple_read_from_buffer(buf, count, ppos, engines, strlen(engines)); + s_str = seq_buf_str(&s); + return simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str)); } static const struct file_operations sched_group_engines_fops = { @@ -663,15 +665,15 @@ static ssize_t control_write(struct file file, const char __user buf, size_t c static ssize_t control_read(struct file file, char __user buf, size_t count, loff_t ppos) { char help[128]; + struct seq_buf s; size_t n; - help[0] = '\0'; + seq_buf_init(&s, help, sizeof(help)); for (n = 0; n < ARRAY_SIZE(control_cmds); n++) { - strlcat(help, control_cmds[n].cmd, sizeof(help)); - strlcat(help, "\n", sizeof(help)); + seq_buf_printf(&s, "%s\n", control_cmds[n].cmd); } - return simple_read_from_buffer(buf, count, ppos, help, strlen(help)); + return simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s)); } static const struct file_operations control_ops = { diff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c index 880a0c79148cd..d13d2d6202ee5 100644 --- a/drivers/input/mouse/synaptics_usb.c +++ b/drivers/input/mouse/synaptics_usb.c @@ -41,6 +41,7 @@ #include <linux/usb.h> #include <linux/input.h> #include <linux/usb/input.h> +#include <linux/seq_buf.h> #define USB_VENDOR_ID_SYNAPTICS 0x06cb #define USB_DEVICE_ID_SYNAPTICS_TP 0x0001 /* Synaptics USB TouchPad / @@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface intf, struct input_dev input_dev; unsigned int intf_num = intf->cur_altsetting->desc.bInterfaceNumber; unsigned int altsetting = min(intf->num_altsetting, 1U); + struct seq_buf s; + char path[64]; int error; error = usb_set_interface(udev, intf_num, altsetting); @@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface intf, ep->bInterval); synusb->urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP; + seq_buf_init(&s, synusb->name, sizeof(synusb->name)); + if (udev->manufacturer) - strscpy(synusb->name, udev->manufacturer, - sizeof(synusb->name)); + seq_buf_puts(&s, udev->manufacturer); if (udev->product) { if (udev->manufacturer) - strlcat(synusb->name, " ", sizeof(synusb->name)); - strlcat(synusb->name, udev->product, sizeof(synusb->name)); + seq_buf_puts(&s, " "); + seq_buf_puts(&s, udev->product); } - if (!strlen(synusb->name)) - snprintf(synusb->name, sizeof(synusb->name), - "USB Synaptics Device %04x:%04x", - le16_to_cpu(udev->descriptor.idVendor), - le16_to_cpu(udev->descriptor.idProduct)); + if (!seq_buf_used(&s)) + seq_buf_printf(&s, "USB Synaptics Device %04x:%04x", + le16_to_cpu(udev->descriptor.idVendor), + le16_to_cpu(udev->descriptor.idProduct)); if (synusb->flags & SYNUSB_STICK) - strlcat(synusb->name, " (Stick)", sizeof(synusb->name)); + seq_buf_puts(&s, " (Stick)"); + + seq_buf_str(&s); - usb_make_path(udev, synusb->phys, sizeof(synusb->phys)); - strlcat(synusb->phys, "/input0", sizeof(synusb->phys)); + usb_make_path(udev, path, sizeof(path)); + snprintf(synusb->phys, sizeof(synusb->phys), "%s/input0", path); input_dev->name = synusb->name; input_dev->phys = synusb->phys; diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c index f1241b63aa5ce..bd15eb58fc84f 100644 --- a/drivers/media/dvb-frontends/si2165.c +++ b/drivers/media/dvb-frontends/si2165.c @@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client client) chip_name, rev_char, state->chip_type, state->chip_revcode); - strlcat(state->fe.ops.info.name, chip_name, - sizeof(state->fe.ops.info.name)); + snprintf(state->fe.ops.info.name, sizeof(state->fe.ops.info.name), + "Silicon Labs %s%s%s", + chip_name, + state->has_dvbt ? " DVB-T" : "", + state->has_dvbc ? " DVB-C" : ""); n = 0; - if (state->has_dvbt) { + if (state->has_dvbt) state->fe.ops.delsys[n++] = SYS_DVBT; - strlcat(state->fe.ops.info.name, " DVB-T", - sizeof(state->fe.ops.info.name)); - } - if (state->has_dvbc) { + if (state->has_dvbc) state->fe.ops.delsys[n++] = SYS_DVBC_ANNEX_A; - strlcat(state->fe.ops.info.name, " DVB-C", - sizeof(state->fe.ops.info.name)); - } / return fe pointer / pdata->fe = &state->fe; diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h index 1b6a8fbaa6485..9f792128a0efe 100644 --- a/drivers/net/ethernet/intel/i40e/i40e.h +++ b/drivers/net/ethernet/intel/i40e/i40e.h @@ -1059,19 +1059,26 @@ static inline char i40e_nvm_version_str(struct i40e_hw hw, char buf, size_t len) { char ver[16] = " "; + size_t offset; / Get NVM version / i40e_info_nvm_ver(hw, buf, len); / Append EETrackID if provided / i40e_info_eetrack(hw, &ver[1], sizeof(ver) - 1); - if (strlen(ver) > 1) - strlcat(buf, ver, len); + if (strlen(ver) > 1) { + offset = strlen(buf); + if (offset < len) + snprintf(buf + offset, len - offset, "%s", ver); + } / Append combo image version if provided / i40e_info_civd_ver(hw, &ver[1], sizeof(ver) - 1); - if (strlen(ver) > 1) - strlcat(buf, ver, len); + if (strlen(ver) > 1) { + offset = strlen(buf); + if (offset < len) + snprintf(buf + offset, len - offset, "%s", ver); + } return buf; } diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c index 479b2418ca340..fcc9e9eb57322 100644 --- a/drivers/net/wireless/ath/wil6210/wmi.c +++ b/drivers/net/wireless/ath/wil6210/wmi.c @@ -7,6 +7,7 @@ #include <linux/moduleparam.h> #include <linux/etherdevice.h> #include <linux/if_arp.h> +#include <linux/seq_buf.h> #include "wil6210.h" #include "txrx.h" @@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv wil) static void resume_triggers2string(u32 triggers, char string, int str_size) { - string[0] = '\0'; + struct seq_buf s; + + seq_buf_init(&s, string, str_size); if (!triggers) { - strlcat(string, " UNKNOWN", str_size); - return; - } + seq_buf_puts(&s, " UNKNOWN"); + } else { + if (triggers & WMI_RESUME_TRIGGER_HOST) + seq_buf_puts(&s, " HOST"); - if (triggers & WMI_RESUME_TRIGGER_HOST) - strlcat(string, " HOST", str_size); + if (triggers & WMI_RESUME_TRIGGER_UCAST_RX) + seq_buf_puts(&s, " UCAST_RX"); - if (triggers & WMI_RESUME_TRIGGER_UCAST_RX) - strlcat(string, " UCAST_RX", str_size); + if (triggers & WMI_RESUME_TRIGGER_BCAST_RX) + seq_buf_puts(&s, " BCAST_RX"); - if (triggers & WMI_RESUME_TRIGGER_BCAST_RX) - strlcat(string, " BCAST_RX", str_size); + if (triggers & WMI_RESUME_TRIGGER_WMI_EVT) + seq_buf_puts(&s, " WMI_EVT"); - if (triggers & WMI_RESUME_TRIGGER_WMI_EVT) - strlcat(string, " WMI_EVT", str_size); + if (triggers & WMI_RESUME_TRIGGER_DISCONNECT) + seq_buf_puts(&s, " DISCONNECT"); + } - if (triggers & WMI_RESUME_TRIGGER_DISCONNECT) - strlcat(string, " DISCONNECT", str_size); + seq_buf_str(&s); } int wmi_resume(struct wil6210_priv wil) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c index 22ff326f1924a..2f74a952599ec 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c @@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev, fwreq->n_items = n_fwnames; for (j = 0; j < n_fwnames; j++) { - fwreq->items[j].path = fwnames[j].path; - fwnames[j].path[0] = '\0'; /* check if firmware path is provided by module parameter / if (brcmf_mp_global.firmware_path[0] != '\0') { - strscpy(fwnames[j].path, mp_path, - BRCMF_FW_NAME_LEN); - - if (end != '/') { - strlcat(fwnames[j].path, "/", - BRCMF_FW_NAME_LEN); - } + snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s", + mp_path, (end == '/') ? "" : "/", + mapping_table[i].fw_base, + fwnames[j].extension); + } else { + snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s", + mapping_table[i].fw_base, + fwnames[j].extension); } - strlcat(fwnames[j].path, mapping_table[i].fw_base, - BRCMF_FW_NAME_LEN); - strlcat(fwnames[j].path, fwnames[j].extension, - BRCMF_FW_NAME_LEN); fwreq->items[j].path = fwnames[j].path; } diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index a64afc3ded3d4..311021a83f03e 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char cmdline) const void rng_seed; const void fdt = initial_boot_params; + if (!fdt) + goto handle_cmdline; + node = fdt_path_offset(fdt, "/chosen"); if (node < 0) node = fdt_path_offset(fdt, "/chosen@0"); @@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char cmdline) / #ifdef CONFIG_CMDLINE #if defined(CONFIG_CMDLINE_EXTEND) - strlcat(cmdline, " ", COMMAND_LINE_SIZE); - strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + { + size_t len = strlen(cmdline); + + if (len < COMMAND_LINE_SIZE) + snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE); + } #elif defined(CONFIG_CMDLINE_FORCE) strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); #else diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c index 5ecc9ed4c44db..0d639eec689c0 100644 --- a/drivers/pinctrl/samsung/pinctrl-samsung.c +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c @@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device dev, struct samsung_pinctrl_dr bank = d->pin_banks; for (i = 0; i < d->nr_banks; ++i, ++bank) { - strscpy(node_name, bank->name, sizeof(node_name)); - len = strlcat(node_name, suffix, sizeof(node_name)); + len = snprintf(node_name, sizeof(node_name), "%s%s", bank->name, suffix); if (len >= sizeof(node_name)) { dev_err(dev, "Too long pin bank name '%s', ignoring\n", bank->name); diff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c index 9b57312f43f50..9fe0343c0b321 100644 --- a/drivers/scsi/bfa/bfa_fcs.c +++ b/drivers/scsi/bfa/bfa_fcs.c @@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s fabric) bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model); - /* Model name/number / - strscpy(port_cfg->sym_name.symname, model, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Driver Version / - strlcat(port_cfg->sym_name.symname, driver_info->version, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Host machine name / - strlcat(port_cfg->sym_name.symname, - driver_info->host_machine_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - / * Host OS Info : * If OS Patch Info is not there, do not truncate any bytes from the * OS name string and instead copy the entire OS info string (64 bytes). / if (driver_info->host_os_patch[0] == '\0') { - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); + snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s%s%s%s%s%s%s%s", + model, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR); } else { - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Append host OS Patch Info / - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_patch, - BFA_SYMNAME_MAXLEN); + snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s%s%s%s%s%s%s%s%s", + model, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_patch); } / null terminate / @@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s fabric) bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model); - /* Model name/number / - strscpy(port_cfg->node_sym_name.symname, model, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Driver Version / - strlcat(port_cfg->node_sym_name.symname, (char )driver_info->version, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - /* Host machine name / - strlcat(port_cfg->node_sym_name.symname, - driver_info->host_machine_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / null terminate / - port_cfg->node_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0; + / Model name/number, Driver Version, Host machine name / + snprintf(port_cfg->node_sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR, + model, (char )driver_info->version, + driver_info->host_machine_name); } /* diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c index 432612d224374..a28208414aec2 100644 --- a/fs/nfs/nfsroot.c +++ b/fs/nfs/nfsroot.c @@ -173,12 +173,15 @@ static int __init root_nfs_cat(char dest, const char src, const size_t destlen) { size_t len = strlen(dest); + int ret; - if (len && dest[len - 1] != ',') - if (strlcat(dest, ",", destlen) >= destlen) - return -1; + if (len >= destlen) + return -1; + + ret = snprintf(dest + len, destlen - len, "%s%s", + (len && dest[len - 1] != ',') ? "," : "", src); - if (strlcat(dest, src, destlen) >= destlen) + if (ret < 0 \|\| ret >= destlen - len) return -1; return 0; } diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c index 9f94919a6bc62..6e2f9887eab4b 100644 --- a/fs/orangefs/orangefs-debugfs.c +++ b/fs/orangefs/orangefs-debugfs.c @@ -37,6 +37,7 @@ / #include <linux/debugfs.h> #include <linux/slab.h> +#include <linux/seq_buf.h> #include <linux/uaccess.h> @@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot) char client_title = "Client Debug Keywords:\n"; char kernel_title = "Kernel Debug Keywords:\n"; size_t string_size = DEBUG_HELP_STRING_SIZE; - size_t result_size; size_t i; char new; int rc = -EINVAL; + struct seq_buf s; gossip_debug(GOSSIP_UTILS_DEBUG, "%s: start\n", __func__); @@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot) goto out; } + seq_buf_init(&s, new, string_size); + /* - * strlcat(dst, src, size) will append at most - * "size - strlen(dst) - 1" bytes of src onto dst, - * null terminating the result, and return the total - * length of the string it tried to create. - * * We'll just plow through here building our new debug - * help string and let strlcat take care of assuring that + * help string and let seq_buf take care of assuring that * dst doesn't overflow. / - strlcat(new, client_title, string_size); + seq_buf_puts(&s, client_title); if (!at_boot) { @@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot) goto out; } - for (i = 0; i < cdm_element_count; i++) { - strlcat(new, "\t", string_size); - strlcat(new, cdm_array[i].keyword, string_size); - strlcat(new, "\n", string_size); - } + for (i = 0; i < cdm_element_count; i++) + seq_buf_printf(&s, "\t%s\n", cdm_array[i].keyword); } - strlcat(new, "\n", string_size); - strlcat(new, kernel_title, string_size); + seq_buf_puts(&s, "\n"); + seq_buf_puts(&s, kernel_title); - for (i = 0; i < num_kmod_keyword_mask_map; i++) { - strlcat(new, "\t", string_size); - strlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size); - result_size = strlcat(new, "\n", string_size); - } + for (i = 0; i < num_kmod_keyword_mask_map; i++) + seq_buf_printf(&s, "\t%s\n", s_kmod_keyword_mask_map[i].keyword); / See if we tried to put too many bytes into "new"... / - if (result_size >= string_size) { + if (seq_buf_has_overflowed(&s)) { kfree(new); goto out; } @@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot) } else { mutex_lock(&orangefs_help_file_lock); memset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE); - strlcat(debug_help_string, new, string_size); + strscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE); mutex_unlock(&orangefs_help_file_lock); kfree(new); } diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index cf841dc71feff..0b489124bfcb8 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2) char strcat(char * const POS p, const char q) { const size_t p_size = __member_size(p); - const size_t wanted = strlcat(p, q, p_size); + + if (p_size == SIZE_MAX) + return __underlying_strcat(p, q); + + const size_t p_len = __fortify_strlen(p); + const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q); if (p_size <= wanted) fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p); diff --git a/net/devlink/dev.c b/net/devlink/dev.c index 55959b0ff5ab4..987b071345c41 100644 --- a/net/devlink/dev.c +++ b/net/devlink/dev.c @@ -5,6 +5,7 @@ / #include <linux/device.h> +#include <linux/seq_buf.h> #include <net/genetlink.h> #include <net/sock.h> #include "devl_internal.h" @@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink devlink, { struct devlink_info_req req = {}; const struct nlattr nlattr; + struct seq_buf s; struct sk_buff msg; int rem, err; @@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink devlink, if (err) goto free_msg; + seq_buf_init(&s, buf, len); + s.len = strnlen(buf, len); + nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING, (void )msg->data, msg->len, rem) { const struct nlattr kv; @@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink devlink, nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE, nlattr, rem_kv) { - strlcat(buf, nla_data(kv), len); - strlcat(buf, " ", len); + seq_buf_printf(&s, "%s ", (const char )nla_data(kv)); } } free_msg: diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c index 97ff11973c493..a1e4173e5a538 100644 --- a/net/sunrpc/addr.c +++ b/net/sunrpc/addr.c @@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton); / char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags) { - char portbuf[RPCBIND_MAXUADDRPLEN]; char addrbuf[RPCBIND_MAXUADDRLEN]; unsigned short port; + size_t len; switch (sap->sa_family) { case AF_INET: - if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0) + len = rpc_ntop4(sap, addrbuf, sizeof(addrbuf)); + if (len == 0 \|\| len >= sizeof(addrbuf)) return NULL; port = ntohs(((struct sockaddr_in )sap)->sin_port); break; case AF_INET6: - if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0) + len = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)); + if (len == 0 \|\| len >= sizeof(addrbuf)) return NULL; port = ntohs(((struct sockaddr_in6 )sap)->sin6_port); break; @@ -283,11 +285,8 @@ char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags) return NULL; } - if (snprintf(portbuf, sizeof(portbuf), - ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf)) - return NULL; - - if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf)) + if (snprintf(addrbuf + len, sizeof(addrbuf) - len, + ".%u.%u", port >> 8, port & 0xff) >= sizeof(addrbuf) - len) return NULL; return kstrdup(addrbuf, gfp_flags); @@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net net, const char uaddr, return 0; } EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr); + diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c index 0bb65be021d97..e145099ee02a9 100644 --- a/sound/pci/ac97/ac97_codec.c +++ b/sound/pci/ac97/ac97_codec.c @@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name, pid = look_for_codec_id(snd_ac97_codec_ids, id); if (pid) { - strlcat(name, " ", maxlen); - strlcat(name, pid->name, maxlen); + int l = strlen(name); + if (pid->mask != 0xffffffff) - sprintf(name + strlen(name), " rev %u", id & ~pid->mask); + snprintf(name + l, maxlen - l, " %s rev %u", pid->name, id & ~pid->mask); + else + snprintf(name + l, maxlen - l, " %s", pid->name); if (ac97 && pid->patch) { if ((modem && (pid->flags & AC97_MODEM_PATCH)) \|\| (! modem && ! (pid->flags & AC97_MODEM_PATCH))) @@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name, } } else { int l = strlen(name); + snprintf(name + l, maxlen - l, " id %x", id & 0xff); } } diff --git a/sound/usb/card.c b/sound/usb/card.c index 9307da95efbef..bdca8085fca66 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -25,6 +25,7 @@ #include <linux/list.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/seq_buf.h> #include <linux/ctype.h> #include <linux/usb.h> #include <linux/moduleparam.h> @@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device dev, struct snd_card card = chip->card; const struct usb_audio_device_name preset; const char s = NULL; - int len; + struct seq_buf sb; + char buf; + size_t size; preset = lookup_device_name(chip->usb_id); @@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device dev, s = preset->vendor_name; else if (quirk && quirk->vendor_name) s = quirk->vendor_name; - card->longname = 0; + + seq_buf_init(&sb, card->longname, sizeof(card->longname)); + if (s && s) - strscpy(card->longname, s); + seq_buf_puts(&sb, s); else if (dev->manufacturer && dev->manufacturer) - strscpy(card->longname, dev->manufacturer); - - if (card->longname) { - strim(card->longname); - if (card->longname) - strlcat(card->longname, " ", sizeof(card->longname)); + seq_buf_puts(&sb, dev->manufacturer); + + if (seq_buf_used(&sb)) { + char trimmed; + + seq_buf_str(&sb); + trimmed = strim(card->longname); + if (trimmed != card->longname) + memmove(card->longname, trimmed, strlen(trimmed) + 1); + sb.len = strlen(card->longname); + if (sb.len) + seq_buf_putc(&sb, ' '); } - strlcat(card->longname, card->shortname, sizeof(card->longname)); + seq_buf_puts(&sb, card->shortname); - len = strlcat(card->longname, " at ", sizeof(card->longname)); + seq_buf_puts(&sb, " at "); - if (len < sizeof(card->longname)) - usb_make_path(dev, card->longname + len, sizeof(card->longname) - len); + size = seq_buf_get_buf(&sb, &buf); + if (size > 0) { + int path_len = usb_make_path(dev, buf, size); + + if (path_len >= 0) + seq_buf_commit(&sb, path_len); + else + seq_buf_set_overflow(&sb); + } switch (snd_usb_get_speed(dev)) { case USB_SPEED_LOW: - strlcat(card->longname, ", low speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", low speed"); break; case USB_SPEED_FULL: - strlcat(card->longname, ", full speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", full speed"); break; case USB_SPEED_HIGH: - strlcat(card->longname, ", high speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", high speed"); break; case USB_SPEED_SUPER: - strlcat(card->longname, ", super speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", super speed"); break; case USB_SPEED_SUPER_PLUS: - strlcat(card->longname, ", super speed plus", sizeof(card->longname)); + seq_buf_puts(&sb, ", super speed plus"); break; default: break; } + + seq_buf_str(&sb); } static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio chip) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index ecaa8bc08d7ca..f64ecad4e77ea 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new snd_usb_feature_unit_ctl = &usb_feature_unit_ctl; / static size_t append_ctl_name(struct snd_kcontrol kctl, const char str) { - return strlcat(kctl->id.name, str, sizeof(kctl->id.name)); + size_t len = strlen(kctl->id.name); + + if (len >= sizeof(kctl->id.name)) + return len + strlen(str); + return len + snprintf(kctl->id.name + len, sizeof(kctl->id.name) - len, "%s", str); } /* @@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer, } if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name))) - strlcat(kctl->id.name, " Jack", sizeof(kctl->id.name)); + append_ctl_name(kctl, " Jack"); else get_connector_control_name(mixer, term, is_input, kctl->id.name, sizeof(kctl->id.name));
3/2	2026/09/15 11:08	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 20696 output: 21 thoughts: 2291 Thoughts: Fuzzing Decision for the Commit Okay, here's the breakdown. The task is to determine if this commit warrants fuzzing with syzkaller, given the instructions and the target architecture (amd64). Let's start by considering the patch in the abstract, and then reviewing specific components. First, I see the core change is replacing instances of `strlcat()` which is probably happening as part of the effort to deprecate `strlcat()` in the kernel. Now, let's look at the affected files. * Architecture-Specific Files (ARM, Loongarch, MIPS, PARISC, x86): These are generally out since the target is amd64, although there might be corner cases I'll have to investigate if they might be called during early boot. I see x86's setup arch is called at boot, which is probably not fuzzable via syscalls. * Drivers: This is where things get interesting. The instructions point us towards reachable drivers accessible via virtual buses, which includes virtio, USB gadget, loopback, etc. * `drivers/comedi/drivers/comedi_bond.c` looks like comedi, which I'm not sure about. I need to check if comedi devices can be created or configured via ioctl (specifically in `do_dev_config`). * `drivers/input/mouse/synaptics_usb.c` uses `synusb_probe()`. This is reachable via USB emulation in syzkaller. * `drivers/gpu/drm/display/drm_dp_mst_topology.c` and `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c` are Intel graphics related. This is less clear whether they can be effectively reached through syzkaller. * `drivers/net/ethernet/intel/i40e/i40e.h`, `drivers/net/wireless/ath/wil6210/wmi.c`, `drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c` are network-related drivers. * `drivers/scsi/bfa/bfa_fcs.c` is a Fibre Channel HBA driver, probably not reachable. * `drivers/media/dvb-frontends/si2165.c` DVB, `drivers/of/fdt.c` flatten device tree, and `drivers/pinctrl/samsung/pinctrl-samsung.c` looks unlikely to be reachable. * `drivers/edac/thunderx_edac.c` is ARM64, and likely not relevant for amd64 fuzzing, but I should probably confirm this. * Filesystems: `fs/nfs/nfsroot.c` and `fs/orangefs/orangefs-debugfs.c`. NFS root setup might be worth a look, and orangefs debugfs sounds interesting, even if less likely to trigger issues. * Core Subsystems: The most relevant area here is `include/linux/fortify-string.h` and also `net/devlink/dev.c`, `net/sunrpc/addr.c`, `sound/pci/ac97/ac97_codec.c`, and `sound/usb/card.c` and `sound/usb/mixer.c`. This involves `strcat` with fortification. I should be able to target the USB audio drivers. Okay, let's go back and examine the implications of this commit, and then evaluate the criteria in the guidelines more closely. The original code in `include/linux/fortify-string.h` is replaced by the following logic: ```c char strcat(char const POS p, const char *q) { const size_t p_size = __member_size(p); if (p_size == SIZE_MAX) return __underlying_strcat(p, q); const size_t p_len = __fortify_strlen(p); const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q); if (p_size <= wanted) fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p); } ``` The new definition of `strcat()` uses `__builtin_snprintf()` instead of `strlcat
4/2	2026/09/15 11:08	tool	grepper	0m Args: { "Expression": "rpc_sockaddr2uaddr" } Results: { "Output": "fs/nfs/flexfilelayout/flexfilelayout.c=2770=ff_layout_ntop6_noscopeid(const struct sockaddr sap, char buf,\n--\nfs/nfs/flexfilelayout/flexfilelayout.c-2807-\nfs/nfs/flexfilelayout/flexfilelayout.c:2808:/* Derived from rpc_sockaddr2uaddr /\nfs/nfs/flexfilelayout/flexfilelayout.c-2809-static void\n--\ninclude/linux/sunrpc/addr.h=17=size_t\t\trpc_pton(struct net , const char , const size_t,\ninclude/linux/sunrpc/addr.h-18-\t\t\t struct sockaddr , const size_t);\ninclude/linux/sunrpc/addr.h:19:char \t\trpc_sockaddr2uaddr(const struct sockaddr , gfp_t);\ninclude/linux/sunrpc/addr.h-20-size_t\t\trpc_uaddr2sockaddr(struct net , const char , const size_t,\n--\nnet/sunrpc/addr.c=254=EXPORT_SYMBOL_GPL(rpc_pton);\n--\nnet/sunrpc/addr.c-256-/*\nnet/sunrpc/addr.c:257: rpc_sockaddr2uaddr - Construct a universal address string from @sap.\nnet/sunrpc/addr.c-258- * @sap: socket address\n--\nnet/sunrpc/addr.c-264- /\nnet/sunrpc/addr.c:265:char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags)\nnet/sunrpc/addr.c-266-{\n--\nnet/sunrpc/rpcb_clnt.c=482=static int rpcb_register_inet4(struct sunrpc_net sn,\n--\nnet/sunrpc/rpcb_clnt.c-491-\nnet/sunrpc/rpcb_clnt.c:492:\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);\nnet/sunrpc/rpcb_clnt.c-493-\tif (!map-\u003er_addr)\n--\nnet/sunrpc/rpcb_clnt.c=510=static int rpcb_register_inet6(struct sunrpc_net sn,\n--\nnet/sunrpc/rpcb_clnt.c-519-\nnet/sunrpc/rpcb_clnt.c:520:\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);\nnet/sunrpc/rpcb_clnt.c-521-\tif (!map-\u003er_addr)\n--\nnet/sunrpc/rpcb_clnt.c=673=void rpcb_getport_async(struct rpc_task task)\n--\nnet/sunrpc/rpcb_clnt.c-759-\t\tmap-\u003er_netid = xprt-\u003eaddress_strings[RPC_DISPLAY_NETID];\nnet/sunrpc/rpcb_clnt.c:760:\t\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, rpc_task_gfp_mask());\nnet/sunrpc/rpcb_clnt.c-761-\t\tif (!map-\u003er_addr) {\n" }
5/2	2026/09/15 11:08	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 24874 output: 23 thoughts: 29 Thoughts: Okay, let's dive into this. Here's how I'd approach that kernel code query: Finding the Callers of `__devlink_compat_running_version` Alright, so I need to understand where `__devlink_compat_running_version` is being used. First instinct is to jump into the `net/devlink/dev.c` file – that's the logical starting point, considering what's in the text. I'm going to quickly scan that file directly. I'll likely use my editor's search function, likely with the command `grep __devlink_compat_running_version net/devlink/dev.c` in the terminal for a more focused search and also to potentially check other kernel directories and source files. The goal is pinpoint exactly which functions call that specific function. I'm not just looking for direct calls, either. I want to see how it's being used – what are the surrounding code blocks, what data is being passed, and what's the overall context. This will provide some important insight into it. Understanding those relationships is the critical part in diagnosing any issue. Once I have the call sites identified, I'll then examine the surrounding code to determine the purpose and impact of the function call in order to understand how the compatibility version is being handled. This is where the real understanding comes from.
6/2	2026/09/15 11:08	tool	grepper	0m Args: { "Expression": "__devlink_compat_running_version" } Results: { "Output": "net/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c=1224=void devlink_compat_running_version(struct devlink *devlink,\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n" }
7/2	2026/09/15 11:08	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25474 output: 22 thoughts: 18 Thoughts: Here's my thought process, as if I were analyzing that code: Finding the Callers of `devlink_compat_running_version` Okay, so I need to understand where this `devlink_compat_running_version` function is being used. This usually means I'm trying to figure out how its return value is being interpreted and what implications that has for the overall system. I'll start by doing a quick search for all the call sites of this function within the codebase. That should give me a map of the relevant execution paths and the broader contexts in which it matters. From there, I can begin to assess what logic depends on this particular version number and try to determine where any potential compatibility issues might arise. I'll need to pay close attention to the data types involved in the calls and the conditions being checked; that will be critical for understanding any branching behavior.
8/2	2026/09/15 11:08	tool	grepper	0m Args: { "Expression": "devlink_compat_running_version" } Results: { "Output": "include/net/devlink.h=2121=void devlink_put(struct devlink devlink);\ninclude/net/devlink.h-2122-\ninclude/net/devlink.h:2123:void devlink_compat_running_version(struct devlink devlink,\ninclude/net/devlink.h-2124-\t\t\t\t char buf, size_t len);\n--\ninclude/net/devlink.h=2146=static inline void\ninclude/net/devlink.h:2147:devlink_compat_running_version(struct devlink devlink, char buf, size_t len)\ninclude/net/devlink.h-2148-{\n--\nnet/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c-1223-\nnet/devlink/dev.c:1224:void devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1225-\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n--\nnet/ethtool/ioctl.c=3646=int dev_ethtool(struct net net, struct ifreq ifr, void __user useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t state-\u003einfo.fw_version,\n" }
9/2	2026/09/15 11:08	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 26302 output: 29 thoughts: 213 Thoughts: My Initial Scan of Potential Code Paths Okay, so I've got a bit of a breadcrumb trail here. First, I see that `net/ethtool/ioctl.c` calls `devlink_compat_running_version` which is, of course, accessible through `dev_ethtool` ioctl. Hmm, that could be interesting. I'll need to remember that as I move forward. Now, let's switch gears and delve into the sound subsystem. I need to check `sound/usb/card.c` and `sound/usb/mixer.c`. Right, in `sound/usb/card.c`, I see `usb_audio_make_longname`. This one is reached through `snd_usb_audio_create`, which in turn is called from `usb_audio_probe`. Pretty standard USB audio setup, but worth noting. Meanwhile, `sound/usb/mixer.c` reveals `append_ctl_name`. This one is a bit more interesting, triggered via `build_connector_control` in the USB audio mixer probe. Switching gears once more, now I'm looking at `drivers/input/mouse/synaptics_usb.c`. In this case, `synusb_probe` gets called when a USB device with a matching ID is attached. This is another area of interest. Then finally, I want to explore `drivers/comedi/drivers/comedi_bond.c` and specifically `do_dev_config`. This might be a good place to look for other callers or get a sense of how `comedi_bond` works in this case.
10/2	2026/09/15 11:09	tool	grepper	0m Args: { "Expression": "do_dev_config", "PathPrefix": "drivers/comedi" } Results: { "Output": "drivers/comedi/drivers/comedi_bond.c=125=static int bonding_dio_insn_config(struct comedi_device dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-169-\ndrivers/comedi/drivers/comedi_bond.c:170:static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\ndrivers/comedi/drivers/comedi_bond.c-171-{\n--\ndrivers/comedi/drivers/comedi_bond.c=271=static int bonding_attach(struct comedi_device dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-284-\t */\ndrivers/comedi/drivers/comedi_bond.c:285:\tret = do_dev_config(dev, it);\ndrivers/comedi/drivers/comedi_bond.c-286-\tif (ret)\n" }
11/2	2026/09/15 11:09	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 27142 output: 21 thoughts: 75 Thoughts: Here's my summary, as though I were thinking through the problem: Analyzing the Comedi and DRM Interactions Okay, so `bonding_attach` is a `COMEDI_DEVCONFIG` ioctl callback for Comedi. Right, it's designed to specifically link `comedi_bond` functionality to comedi minors. That's good to remember. This strongly suggests a system-level interaction, potentially involving multiplexing or device aggregation within the Comedi framework. Now, my attention is drawn to `drivers/gpu/drm/display/drm_dp_mst_topology.c`. I need to figure out how this is connected. Let me check where `build_mst_prop_path` is called within that file. I need to understand the potential dependency, especially if it relates to path or topology construction related to a MST connection. This could reveal the nature of the integration – potentially a shared resource, or some configuration information being passed between these two disparate subsystems. Gotta trace that call.
12/2	2026/09/15 11:09	tool	grepper	0m Args: { "Expression": "build_mst_prop_path" } Results: { "Output": "drivers/gpu/drm/display/drm_dp_mst_topology.c=2192=static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch mstb, guid_t guid)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2214-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2215:static void build_mst_prop_path(const struct drm_dp_mst_branch mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2216-\t\t\t\tint pnum,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=2278=drm_dp_mst_port_add_connector(struct drm_dp_mst_branch mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2284-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2285:\tbuild_mst_prop_path(mstb, port-\u003eport_num, proppath, sizeof(proppath));\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2286-\tport-\u003econnector = mgr-\u003ecbs-\u003eadd_connector(mgr, port, proppath);\n" }
13/2	2026/09/15 11:09	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 27792 output: 38 thoughts: 35 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue: Diving into the `fortify-string.h` Rabbit Hole Alright, so the conversation's veering towards `include/linux/fortify-string.h`. Naturally, my mind immediately jumps to a deeper dive. Let's see, what specifically is being discussed? It's time to thoroughly examine this header file. We're talking about fortification, so likely memory safety and potential buffer overflows... I need to consider how this interacts with the kernel's overall security posture. Is this about compile-time checks, run-time mitigation, or a combination of both? Are we dealing with string manipulation functions and their safer alternatives? The details here can get quite intricate, given the kernel's needs for performance and stability. I need to understand the exact implementation details of the macros and functions defined within. A quick scan won't do; this warrants a focused, analytical inspection to understand its role in preventing common vulnerabilities.
14/2	2026/09/15 11:09	tool	read-file	0m Args: { "File": "include/linux/fortify-string.h", "FirstLine": 355, "LineCount": 35 } Results: { "Contents": " 355:\t * destination buffer size is known to the compiler. Prefer\n 356:\t * building the string with formatting, via scnprintf() or similar.\n 357:\t * At the very least, use strncat().\n 358:\t \n 359:\t Returns @p.\n 360:\t \n 361:\t /\n 362:\t__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)\n 363:\tchar strcat(char const POS p, const char q)\n 364:\t{\n 365:\t\tconst size_t p_size = __member_size(p);\n 366:\t\n 367:\t\tif (p_size == SIZE_MAX)\n 368:\t\t\treturn __underlying_strcat(p, q);\n 369:\t\n 370:\t\tconst size_t p_len = __fortify_strlen(p);\n 371:\t\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n 372:\t\n 373:\t\tif (p_size \u003c= wanted)\n 374:\t\t\tfortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);\n 375:\t\treturn p;\n 376:\t}\n 377:\t\n 378:\t/\n 379:\t strncat - Append a string to an existing string\n 380:\t \n 381:\t @p: pointer to NUL-terminated string to append to\n 382:\t * @q: pointer to source string to append from\n 383:\t * @count: Maximum bytes to read from @q\n 384:\t \n 385:\t Appends at most @count bytes from @q (stopping at the first\n 386:\t * NUL byte) after the NUL-terminated string at @p. @p will be\n 387:\t * NUL-terminated.\n 388:\t \n 389:\t Do not use this function. While FORTIFY_SOURCE tries to avoid\n" }
15/2	2026/09/15 11:09	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 28662 output: 20 thoughts: 941 Thoughts: Analyzing Potential Integer Overflow and String Handling Vulnerabilities Okay, so I'm looking at this fortified `strcat` implementation in `include/linux/fortify-string.h`, and it's making me think. The original version, using `strlcat`, was fine, but this new one... I'm immediately noticing some potential issues. Specifically, this line: ```c const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q); ``` My initial thought is that if `p_size <= p_len`, the call to `__builtin_snprintf` could cause some problems. For one, if `p` wasn't properly null-terminated, or if some obscure scenario led to `p_len` being larger than `p_size`, we could have an integer underflow in `p_size - p_len`. Even if that check prevents overflow, then what happens if the check fails and `p_size == p_len`? This results in `p_size - p_len` being 0, which would pass 0 to `snprintf`. And the function returns `strlen(q)`. Meaning `wanted = p_len + strlen(q) >= p_size`, and the panic will be triggered as it should. It seems safe, but I'll need to double check the math. Of course, the whole point of this file is to fortify the string functions, so I'd expect it to be careful, but I still have to be diligent. It's a fundamental function, so any flaw here could be catastrophic. I'm now also looking at a related function, `sound/usb/card.c` specifically, the `usb_audio_make_longname()` function, as it uses string concatenation. I see this section: ```c size = seq_buf_get_buf(&sb, &buf); int path_len = usb_make_path(dev, buf, size); seq_buf_commit(&sb, path_len); ``` My concern is what does `usb_make_path` actually return? The code seems to assume a positive return value, but it's important to understand the full range of possible values here and how it's being used. I will need to check its definition to ensure that it aligns with the logic in `seq_buf_commit`.
16/2	2026/09/15 11:09	tool	grepper	0m Args: { "Expression": "int usb_make_path" } Results: { "Output": "include/linux/usb.h=954=int usb_hub_release_port(struct usb_device hdev, unsigned port1,\n--\ninclude/linux/usb.h-981- /\ninclude/linux/usb.h:982:static inline int usb_make_path(struct usb_device dev, char buf, size_t size)\ninclude/linux/usb.h-983-{\n" }
17/2	2026/09/15 11:09	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30266 output: 35 thoughts: 20 Thoughts: Here's a summary of my thought process, as requested: Diving into USB Core - Specifically, `usb.h` Okay, time to get my hands dirty. I need to understand something specific about the USB subsystem, and my initial instinct is to go right to the header file. I'm thinking, let's start with `include/linux/usb.h`, that's the canonical definition file for all things USB kernel-side. I'm betting a lot of core structures and maybe some key macros are defined in there. I'm going to jump in around line 982. It's often a good starting point for exploring the low-level details. This area probably contains some fundamental definitions or potentially a section that relates to the specific USB concept I'm interested in. I'll get started there and see where the trail leads.
18/2	2026/09/15 11:09	tool	read-file	0m Args: { "File": "include/linux/usb.h", "FirstLine": 980, "LineCount": 15 } Results: { "Contents": " 980:\t * high speed, and a different one if they are full or low speed.\n 981:\t /\n 982:\tstatic inline int usb_make_path(struct usb_device dev, char buf, size_t size)\n 983:\t{\n 984:\t\tint actual;\n 985:\t\tactual = snprintf(buf, size, \"usb-%s-%s\", dev-\u003ebus-\u003ebus_name,\n 986:\t\t\t\t dev-\u003edevpath);\n 987:\t\treturn (actual \u003e= (int)size) ? -1 : actual;\n 988:\t}\n 989:\t\n 990:\t/-------------------------------------------------------------------------*/\n 991:\t\n 992:\t#define USB_DEVICE_ID_MATCH_DEVICE \\\n 993:\t\t\t(USB_DEVICE_ID_MATCH_VENDOR \| USB_DEVICE_ID_MATCH_PRODUCT)\n 994:\t#define USB_DEVICE_ID_MATCH_DEV_RANGE \\\n" }
19/2	2026/09/15 11:09	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30768 output: 37 thoughts: 1305 Thoughts: Analyzing String Handling and Buffer Management Okay, let's break this down. First, I was looking at `drivers/input/mouse/synaptics_usb.c` and immediately noticed the change from using `usb_make_path` and `strlcat` to `snprintf`. I'm familiar with this pattern – it looks like they're moving towards more robust and potentially safer string manipulation, specifically to avoid buffer overflows. The use of a temporary `path` variable is also a common and good practice. I'm noting this is a shift in how the physical path is constructed, and likely related to a broader code cleanup. Next, I jumped to `synusb_probe`. The changes here are more substantial. I see the introduction of `seq_buf_init` and `seq_buf_puts` instead of direct `strscpy` and `strlcat` calls when building the device name. This is a crucial improvement and a good use case for these helper functions for safe string building. The check for existing manufacturer/product strings also seems cleaner now, using `seq_buf_used` effectively. I particularly appreciate the use of `seq_buf_printf` for the "USB Synaptics Device" fallback, keeping it concise and efficient. It looks like a refactoring to modernize string handling with the seq_buf abstraction. Then, I shifted gears and examined `net/sunrpc/addr.c`. This isn't directly related, but the presence of `snprintf` in `rpc_sockaddr2uaddr` triggered a thought. This reinforces the need for careful buffer management in network code. I'm using `snprintf` to format the port information. I had to check the return value, to be sure the port value could be safely converted. Finally, I dove into `net/devlink/dev.c` and specifically `__devlink_compat_running_version`. This function utilizes `seq_buf_printf` to construct a version string. My mind immediately went to the null termination of the buffer. I'm familiar with these issues. The code calls `seq_buf_init` and sets `s.len` with `strnlen`. That tells me that `seq_buf_init` doesn't implicitly null-terminate, unlike some other string functions. The code then iterates through nested attributes and uses `seq_buf_printf`. I needed to confirm whether `seq_buf_str(&s)` is called at the end, or whether there is an explicit null termination after the `for` loop. If not, I'm left thinking that the buffer could be not null-terminated, which could lead to subtle bugs or security issues. I'll need to read the surrounding code to determine if the buffer is properly null-terminated later. Let's see if I have it right! I'm going to look at lines 1180 to 1240 of `net/devlink/dev.c`!
20/2	2026/09/15 11:10	tool	read-file	0m Args: { "File": "net/devlink/dev.c", "FirstLine": 1188, "LineCount": 55 } Results: { "Contents": "1188:\t\n1189:\tstatic void __devlink_compat_running_version(struct devlink devlink,\n1190:\t\t\t\t\t\t char buf, size_t len)\n1191:\t{\n1192:\t\tstruct devlink_info_req req = {};\n1193:\t\tconst struct nlattr nlattr;\n1194:\t\tstruct seq_buf s;\n1195:\t\tstruct sk_buff msg;\n1196:\t\tint rem, err;\n1197:\t\n1198:\t\tmsg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);\n1199:\t\tif (!msg)\n1200:\t\t\treturn;\n1201:\t\n1202:\t\treq.msg = msg;\n1203:\t\terr = devlink-\u003eops-\u003einfo_get(devlink, \u0026req, NULL);\n1204:\t\tif (err)\n1205:\t\t\tgoto free_msg;\n1206:\t\n1207:\t\tseq_buf_init(\u0026s, buf, len);\n1208:\t\ts.len = strnlen(buf, len);\n1209:\t\n1210:\t\tnla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,\n1211:\t\t\t\t (void )msg-\u003edata, msg-\u003elen, rem) {\n1212:\t\t\tconst struct nlattr kv;\n1213:\t\t\tint rem_kv;\n1214:\t\n1215:\t\t\tnla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,\n1216:\t\t\t\t\t\t nlattr, rem_kv) {\n1217:\t\t\t\tseq_buf_printf(\u0026s, \"%s \", (const char )nla_data(kv));\n1218:\t\t\t}\n1219:\t\t}\n1220:\tfree_msg:\n1221:\t\tnlmsg_consume(msg);\n1222:\t}\n1223:\t\n1224:\tvoid devlink_compat_running_version(struct devlink devlink,\n1225:\t\t\t\t\t char buf, size_t len)\n1226:\t{\n1227:\t\tif (!devlink-\u003eops-\u003einfo_get)\n1228:\t\t\treturn;\n1229:\t\n1230:\t\tdevl_lock(devlink);\n1231:\t\tif (devl_is_registered(devlink))\n1232:\t\t\t__devlink_compat_running_version(devlink, buf, len);\n1233:\t\tdevl_unlock(devlink);\n1234:\t}\n1235:\t\n1236:\tint devlink_compat_flash_update(struct devlink devlink, const char *file_name)\n1237:\t{\n1238:\t\tstruct devlink_flash_update_params params = {};\n1239:\t\tint ret;\n1240:\t\n1241:\t\tdevl_lock(devlink);\n1242:\t\tif (!devl_is_registered(devlink)) {\n" }
21/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33568 output: 19 thoughts: 234 Thoughts: Examining `__devlink_compat_running_version` Okay, let's dive into this `__devlink_compat_running_version` function. I see the code, and I'm immediately drawn to the way it handles the output using `seq_buf`. It looks like it's iterating through some Netlink attributes to pull out running version information. Specifically, it seems to initialize a `seq_buf` and then processes nested attributes within `DEVLINK_ATTR_INFO_VERSION_RUNNING` using `nla_for_each_nested_type`. For each version value found within `DEVLINK_ATTR_INFO_VERSION_VALUE`, it's printing it to the `seq_buf` with a space using `seq_buf_printf`. But a key question immediately springs to mind: What exactly does `seq_buf_printf` do under the hood? Does it guarantee null-termination if the buffer hits its capacity? Or is there potential for issues with string truncation or unexpected behavior? I need to understand the behavior of `seq_buf` to ensure this code is robust. Time to crack open `include/linux/seq_buf.h` to refresh my understanding of how this structure works. I need to make sure I'm not overlooking any potential buffer overflow issues here.
22/2	2026/09/15 11:10	tool	grepper	0m Args: { "Expression": "seq_buf_str" } Results: { "Output": "block/partitions/core.c=119=static struct parsed_partitions check_partition(struct gendisk hd)\n--\nblock/partitions/core.c-154-\tif (res \u003e 0) {\nblock/partitions/core.c:155:\t\tprintk(KERN_INFO \"%s\", seq_buf_str(\u0026state-\u003epp_buf));\nblock/partitions/core.c-156-\n--\nblock/partitions/core.c-169-\t\t\t \" unable to read partition table\\n\");\nblock/partitions/core.c:170:\t\tprintk(KERN_INFO \"%s\", seq_buf_str(\u0026state-\u003epp_buf));\nblock/partitions/core.c-171-\t}\n--\ndrivers/android/tests/binder_alloc_kunit.c=299=static void permute_frees(struct kunit test, struct binder_alloc alloc,\n--\ndrivers/android/tests/binder_alloc_kunit.c-319-\t\t\t\t tc-\u003efront_pages ? \"front\" : \"back \",\ndrivers/android/tests/binder_alloc_kunit.c:320:\t\t\t\t seq_buf_str(\u0026tc-\u003ealignments_sb),\ndrivers/android/tests/binder_alloc_kunit.c:321:\t\t\t\t seq_buf_str(\u0026freeseq_sb));\ndrivers/android/tests/binder_alloc_kunit.c-322-\t\t}\n--\ndrivers/comedi/drivers/comedi_bond.c=170=static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\n--\ndrivers/comedi/drivers/comedi_bond.c-265-\ndrivers/comedi/drivers/comedi_bond.c:266:\tseq_buf_str(\u0026s);\ndrivers/comedi/drivers/comedi_bond.c-267-\n--\ndrivers/edac/thunderx_edac.c=1102=static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void irq_id)\n--\ndrivers/edac/thunderx_edac.c-1153-\t\tif (ctx-\u003ereg_com_int \u0026 OCX_COM_INT_CE)\ndrivers/edac/thunderx_edac.c:1154:\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1155-\n--\ndrivers/edac/thunderx_edac.c=1187=static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void irq_id)\n--\ndrivers/edac/thunderx_edac.c-1225-\t\tif (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_UE)\ndrivers/edac/thunderx_edac.c:1226:\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1227-\t\telse if (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_CE)\ndrivers/edac/thunderx_edac.c:1228:\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1229-\n--\ndrivers/edac/thunderx_edac.c=1844=static irqreturn_t thunderx_l2c_threaded_isr(int irq, void irq_id)\n--\ndrivers/edac/thunderx_edac.c-1909-\t\tif (ctx-\u003ereg_int \u0026 mask_ue)\ndrivers/edac/thunderx_edac.c:1910:\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1911-\t\telse if (ctx-\u003ereg_int \u0026 mask_ce)\ndrivers/edac/thunderx_edac.c:1912:\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1913-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=2215=static void build_mst_prop_path(const struct drm_dp_mst_branch mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2233-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2234:\tseq_buf_str(\u0026s);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2235-}\n--\ndrivers/gpu/drm/drm_edid.c=2814=void drm_edid_print_product_id(struct drm_printer p,\n--\ndrivers/gpu/drm/drm_edid.c-2825-\t\t vend, le16_to_cpu(id-\u003eproduct_code),\ndrivers/gpu/drm/drm_edid.c:2826:\t\t le32_to_cpu(id-\u003eserial_number), seq_buf_str(\u0026date));\ndrivers/gpu/drm/drm_edid.c-2827-\n--\ndrivers/gpu/drm/i915/display/intel_ddi.c=5196=static const char intel_ddi_encoder_name(struct intel_display display,\n--\ndrivers/gpu/drm/i915/display/intel_ddi.c-5225-\ndrivers/gpu/drm/i915/display/intel_ddi.c:5226:\treturn seq_buf_str(s);\ndrivers/gpu/drm/i915/display/intel_ddi.c-5227-}\n--\ndrivers/gpu/drm/i915/display/intel_dp.c=1504=static void intel_dp_print_rates(struct intel_dp intel_dp)\n--\ndrivers/gpu/drm/i915/display/intel_dp.c-1512-\tseq_buf_print_array(\u0026s, intel_dp-\u003esource_rates, intel_dp-\u003enum_source_rates);\ndrivers/gpu/drm/i915/display/intel_dp.c:1513:\tdrm_dbg_kms(display-\u003edrm, \"source rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp.c-1514-\n--\ndrivers/gpu/drm/i915/display/intel_dp.c-1516-\tseq_buf_print_array(\u0026s, intel_dp-\u003esink_rates, intel_dp-\u003enum_sink_rates);\ndrivers/gpu/drm/i915/display/intel_dp.c:1517:\tdrm_dbg_kms(display-\u003edrm, \"sink rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp.c-1518-\n--\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c=269=void intel_dp_link_caps_print_common_rates(struct intel_dp_link_caps link_caps)\n--\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c-277-\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c:278:\tdrm_dbg_kms(display-\u003edrm, \"common rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c-279-}\n--\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c=63=static void log_underrun_dbg1(struct intel_display display, enum pipe pipe,\n--\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c-79-\tdrm_err(display-\u003edrm, \"Pipe %c FIFO underrun info: %s on planes: %s\\n\",\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c:80:\t\tpipe_name(pipe), info, seq_buf_str(\u0026planes_desc));\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c-81-\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=368=static ssize_t sched_group_engines_read(struct file file, char __user buf,\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-396-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:397:\ts_str = seq_buf_str(\u0026s);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-398-\treturn simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));\n--\ndrivers/input/mouse/synaptics_usb.c=273=static int synusb_probe(struct usb_interface intf,\n--\ndrivers/input/mouse/synaptics_usb.c-358-\ndrivers/input/mouse/synaptics_usb.c:359:\tseq_buf_str(\u0026s);\ndrivers/input/mouse/synaptics_usb.c-360-\n--\ndrivers/net/wireless/ath/wil6210/wmi.c=3164=static void resume_triggers2string(u32 triggers, char string, int str_size)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3188-\ndrivers/net/wireless/ath/wil6210/wmi.c:3189:\tseq_buf_str(\u0026s);\ndrivers/net/wireless/ath/wil6210/wmi.c-3190-}\n--\ndrivers/usb/dwc2/hcd_queue.c=376=static void pmap_print(unsigned long map, int bits_per_period,\n--\ndrivers/usb/dwc2/hcd_queue.c-420-\t\tif (printed)\ndrivers/usb/dwc2/hcd_queue.c:421:\t\t\tprint_fn(seq_buf_str(\u0026buf), print_data);\ndrivers/usb/dwc2/hcd_queue.c-422-\t}\n--\ninclude/linux/seq_buf.h=77=static inline unsigned int seq_buf_used(struct seq_buf s)\n--\ninclude/linux/seq_buf.h-82-/*\ninclude/linux/seq_buf.h:83: seq_buf_str - get NUL-terminated C string from seq_buf\ninclude/linux/seq_buf.h-84- * @s: the seq_buf handle\n--\ninclude/linux/seq_buf.h-97- /\ninclude/linux/seq_buf.h:98:static inline const char seq_buf_str(struct seq_buf s)\ninclude/linux/seq_buf.h-99-{\n--\nkernel/bpf/diagnostics.c=336=static void diag_fmt_restore(struct bpf_verifier_env env, struct diag_fmt_mark mark)\n--\nkernel/bpf/diagnostics.c-353-\t\tmark.chunk-\u003eseq.len = mark.len;\nkernel/bpf/diagnostics.c:354:\t\tseq_buf_str(\u0026mark.chunk-\u003eseq);\nkernel/bpf/diagnostics.c-355-\t}\n--\nkernel/bpf/diagnostics.c=608=static void format_disasm_line(struct bpf_verifier_env env, int insn_idx,\n--\nkernel/bpf/diagnostics.c-633-\tprint_bpf_insn(\u0026cbs, insn, env-\u003eallow_ptr_leaks);\nkernel/bpf/diagnostics.c:634:\tseq_buf_str(\u0026ctx.seq);\nkernel/bpf/diagnostics.c-635-\tctx.seq.len = strnlen(line-\u003etext, sizeof(line-\u003etext));\n--\nkernel/bpf/diagnostics.c-637-\t\tseq_buf_pop(\u0026ctx.seq);\nkernel/bpf/diagnostics.c:638:\tseq_buf_str(\u0026ctx.seq);\nkernel/bpf/diagnostics.c-639-\n--\nkernel/panic.c=901=static const char _print_tainted(bool verbose)\n--\nkernel/panic.c-910-\nkernel/panic.c:911:\treturn seq_buf_str(\u0026s);\nkernel/panic.c-912-}\n--\nkernel/rcu/refscale.c=1313=static u64 process_durations(int n)\n--\nkernel/rcu/refscale.c-1335-\t\tif (seq_buf_used(\u0026s) \u003e= 800) {\nkernel/rcu/refscale.c:1336:\t\t\tpr_alert(\"%s\", seq_buf_str(\u0026s));\nkernel/rcu/refscale.c-1337-\t\t\tseq_buf_clear(\u0026s);\n--\nkernel/rcu/refscale.c-1343-\t}\nkernel/rcu/refscale.c:1344:\tpr_alert(\"%s\\n\", seq_buf_str(\u0026s));\nkernel/rcu/refscale.c-1345-\n--\nkernel/sched/core.c=8135=const char preempt_model_str(void)\n--\nkernel/sched/core.c-8157-\t\t\t\t brace ? \"}\" : \"\");\nkernel/sched/core.c:8158:\t\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8159-\t\t}\n--\nkernel/sched/core.c-8163-\t\t\t\t brace ? \"}\" : \"\");\nkernel/sched/core.c:8164:\t\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8165-\t\t}\nkernel/sched/core.c-8166-\nkernel/sched/core.c:8167:\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8168-\t}\n--\nkernel/trace/trace_events.c=4882=static __init int event_trace_enable(void)\n--\nkernel/trace/trace_events.c-4908-\nkernel/trace/trace_events.c:4909:\tseq_buf_str(\u0026bootup_event_seq);\nkernel/trace/trace_events.c-4910-\tearly_enable_events(tr, bootup_event_buf, false);\n--\nkernel/trace/trace_events.c=4930=static __init int event_trace_enable_again(void)\n--\nkernel/trace/trace_events.c-4937-\nkernel/trace/trace_events.c:4938:\tseq_buf_str(\u0026bootup_event_seq);\nkernel/trace/trace_events.c-4939-\tearly_enable_events(tr, bootup_event_buf, true);\n--\nkernel/trace/trace_events_hist.c=2977=find_synthetic_field_var(struct hist_trigger_data target_hist_data,\n--\nkernel/trace/trace_events_hist.c-2991-\t/* Terminate synthetic_name with a NUL. /\nkernel/trace/trace_events_hist.c:2992:\tseq_buf_str(\u0026s);\nkernel/trace/trace_events_hist.c-2993-\n--\nkernel/trace/trace_events_hist.c=3032=create_field_var_hist(struct hist_trigger_data target_hist_data,\n--\nkernel/trace/trace_events_hist.c-3109-\t/* Terminate cmd with a NUL. /\nkernel/trace/trace_events_hist.c:3110:\tseq_buf_str(\u0026s);\nkernel/trace/trace_events_hist.c-3111-\n--\nlib/codetag.c=156=static void get_symbol(struct module mod, const char prefix, const char name)\n--\nlib/codetag.c-165-\nlib/codetag.c:166:\tbuf = seq_buf_str(\u0026sb);\nlib/codetag.c-167-\tpreempt_disable();\n--\nlib/seq_buf.c=115=void seq_buf_do_printk(struct seq_buf s, const char lvl)\n--\nlib/seq_buf.c-121-\nlib/seq_buf.c:122:\tstart = seq_buf_str(s);\nlib/seq_buf.c-123-\twhile ((lf = strchr(start, '\\n'))) {\n--\nlib/tests/seq_buf_kunit.c=11=static void seq_buf_init_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-22-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 0);\nlib/tests/seq_buf_kunit.c:23:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-24-}\n--\nlib/tests/seq_buf_kunit.c=26=static void seq_buf_declare_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-34-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 0);\nlib/tests/seq_buf_kunit.c:35:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-36-}\n--\nlib/tests/seq_buf_kunit.c=38=static void seq_buf_clear_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-44-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:45:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-46-\n--\nlib/tests/seq_buf_kunit.c-50-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:51:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-52-}\n--\nlib/tests/seq_buf_kunit.c=54=static void seq_buf_puts_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-60-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:61:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-62-\n--\nlib/tests/seq_buf_kunit.c-65-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:66:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-67-}\n--\nlib/tests/seq_buf_kunit.c=69=static void seq_buf_puts_overflow_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-79-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 10);\nlib/tests/seq_buf_kunit.c:80:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"123456789\");\nlib/tests/seq_buf_kunit.c-81-\n--\nlib/tests/seq_buf_kunit.c-84-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:85:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-86-}\n--\nlib/tests/seq_buf_kunit.c=88=static void seq_buf_putc_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-97-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:98:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-99-\n--\nlib/tests/seq_buf_kunit.c-102-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:103:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-104-\n--\nlib/tests/seq_buf_kunit.c-107-\tKUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:108:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-109-\n--\nlib/tests/seq_buf_kunit.c-112-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:113:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-114-}\n--\nlib/tests/seq_buf_kunit.c=116=static void seq_buf_printf_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-122-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:123:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-124-\n--\nlib/tests/seq_buf_kunit.c-127-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:128:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world 123\");\nlib/tests/seq_buf_kunit.c-129-}\n--\nlib/tests/seq_buf_kunit.c=131=static void seq_buf_printf_overflow_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-137-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 10);\nlib/tests/seq_buf_kunit.c:138:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"1234567890\");\nlib/tests/seq_buf_kunit.c-139-\n--\nlib/tests/seq_buf_kunit.c-142-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 16);\nlib/tests/seq_buf_kunit.c:143:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"1234567890abcde\");\nlib/tests/seq_buf_kunit.c-144-\n--\nlib/tests/seq_buf_kunit.c-147-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:148:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-149-}\n--\nlib/tests/seq_buf_kunit.c=151=static void seq_buf_get_buf_commit_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-165-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:166:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-167-\n--\nlib/tests/seq_buf_kunit.c-176-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:177:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-178-\n--\nlib/tests/seq_buf_kunit.c=187=static void seq_buf_putmem_hex_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-199-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), strlen(expected));\nlib/tests/seq_buf_kunit.c:200:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), expected);\nlib/tests/seq_buf_kunit.c-201-}\n--\nlib/tests/seq_buf_kunit.c=203=static void seq_buf_putmem_hex_overflow_test(struct kunit test)\n--\nlib/tests/seq_buf_kunit.c-215-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 20);\nlib/tests/seq_buf_kunit.c:216:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), expected);\nlib/tests/seq_buf_kunit.c-217-}\n--\nsound/soc/codecs/cs35l56-shared-test.c=725=static void cs35l56_shared_test_gpio_param_desc(const struct cs35l56_shared_test_param param,\n--\nsound/soc/codecs/cs35l56-shared-test.c-746-\tsnprintf(desc, KUNIT_PARAM_DESC_SIZE, \"gpios:{%s} pulls:{%s} status:%#lx spkid:%d\",\nsound/soc/codecs/cs35l56-shared-test.c:747:\t\t seq_buf_str(\u0026gpios), seq_buf_str(\u0026pulls), param-\u003egpio_status, param-\u003espkid);\nsound/soc/codecs/cs35l56-shared-test.c-748-}\n--\nsound/soc/codecs/cs35l56-test.c=590=static void cs35l56_test_gpio_param_desc(const struct cs35l56_test_param param, char desc)\n--\nsound/soc/codecs/cs35l56-test.c-610-\tsnprintf(desc, KUNIT_PARAM_DESC_SIZE, \"gpios:{%s} pulls:{%s}\",\nsound/soc/codecs/cs35l56-test.c:611:\t\t seq_buf_str(\u0026gpios), seq_buf_str(\u0026pulls));\nsound/soc/codecs/cs35l56-test.c-612-}\n--\nsound/usb/card.c=648=static void usb_audio_make_longname(struct usb_device dev,\n--\nsound/usb/card.c-683-\nsound/usb/card.c:684:\t\tseq_buf_str(\u0026sb);\nsound/usb/card.c-685-\t\ttrimmed = strim(card-\u003elongname);\n--\nsound/usb/card.c-726-\nsound/usb/card.c:727:\tseq_buf_str(\u0026sb);\nsound/usb/card.c-728-}\n" }
23/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41497 output: 36 thoughts: 31 Thoughts: Here's my attempt at summarizing the thought process, as if I were a Linux kernel expert: Understanding the `seq_buf` Implementation Okay, time to dive into the nitty-gritty. I'm going to take a look at the `seq_buf` implementation, specifically the header file `include/linux/seq_buf.h`. I've been meaning to refresh my memory on the details of how this works, and now's as good a time as any. I want to see exactly how the `seq_buf` structure itself is defined, how the buffer allocation and management functions are structured, and what the core principles are behind its design. I'm especially interested in the mechanics of its growth strategy. I need to refresh my mind on the locking strategy and understand how it handles synchronization within a concurrent context. I’m thinking about this because I'm troubleshooting some kernel performance issues, and knowing the low-level details of things like `seq_buf` is crucial for debugging and optimization. It's time to refresh the core concepts in my mind and make sure I know how this utility is designed.
24/2	2026/09/15 11:10	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 80, "LineCount": 40 } Results: { "Contents": " 80:\t}\n 81:\t\n 82:\t/*\n 83:\t seq_buf_str - get NUL-terminated C string from seq_buf\n 84:\t * @s: the seq_buf handle\n 85:\t \n 86:\t This makes sure that the buffer in @s is NUL-terminated and\n 87:\t * safe to read as a string.\n 88:\t \n 89:\t Note, if this is called when the buffer has overflowed, then\n 90:\t * the last byte of the buffer is zeroed, and the len will still\n 91:\t * point passed it.\n 92:\t \n 93:\t After this function is called, s-\u003ebuffer is safe to use\n 94:\t * in string operations.\n 95:\t \n 96:\t Returns: @s-\u003ebuf after making sure it is terminated.\n 97:\t /\n 98:\tstatic inline const char seq_buf_str(struct seq_buf s)\n 99:\t{\n 100:\t\tif (WARN_ON(s-\u003esize == 0))\n 101:\t\t\treturn \"\";\n 102:\t\n 103:\t\tif (seq_buf_buffer_left(s))\n 104:\t\t\ts-\u003ebuffer[s-\u003elen] = 0;\n 105:\t\telse\n 106:\t\t\ts-\u003ebuffer[s-\u003esize - 1] = 0;\n 107:\t\n 108:\t\treturn s-\u003ebuffer;\n 109:\t}\n 110:\t\n 111:\t/\n 112:\t seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t \n 116:\t Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t /\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf s, char **bufp)\n" }
25/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42370 output: 34 thoughts: 408 Thoughts: Analyzing `net/devlink/dev.c`'s `__devlink_compat_running_version` Okay, let's dive back into `net/devlink/dev.c` and specifically this function, `__devlink_compat_running_version`. I see it's handling the retrieval and formatting of the running version information. It's using `netlink` which is pretty standard for these sorts of device interactions. It looks like it's constructing a netlink message (`req`) and then calling the device's specific `info_get` function. It then uses a `seq_buf` to build the string representation of the version. Hold on... something feels off. I'm looking at how it processes the attributes within the netlink message, and specifically, the nested attributes under `DEVLINK_ATTR_INFO_VERSION_RUNNING` and then `DEVLINK_ATTR_INFO_VERSION_VALUE`. It loops through and prints the value of each. However, I don't see any explicit null-termination of the `seq_buf`. It looks like it's just building the string directly into a buffer. Ah ha! I'm pretty sure `seq_buf_printf` itself does not null-terminate. That could be a problem! I need to verify whether the buffer is null-terminated or not. I'd better confirm this, so let's jump over to `lib/seq_buf.c` and take a look at the definition of `seq_buf_vprintf` because that's what `seq_buf_printf` calls.
26/2	2026/09/15 11:10	tool	read-file	0m Args: { "File": "lib/seq_buf.c", "FirstLine": 55, "LineCount": 50 } Results: { "Contents": " 55:\t}\n 56:\t\n 57:\t/*\n 58:\t seq_buf_vprintf - sequence printing of information.\n 59:\t * @s: seq_buf descriptor\n 60:\t * @fmt: printf format string\n 61:\t * @args: va_list of arguments from a printf() type function\n 62:\t \n 63:\t Writes a vnprintf() format into the sequence buffer.\n 64:\t \n 65:\t Returns: zero on success, -1 on overflow.\n 66:\t /\n 67:\tint seq_buf_vprintf(struct seq_buf s, const char fmt, va_list args)\n 68:\t{\n 69:\t\tint len;\n 70:\t\n 71:\t\tWARN_ON(s-\u003esize == 0);\n 72:\t\n 73:\t\tif (s-\u003elen \u003c s-\u003esize) {\n 74:\t\t\tlen = vsnprintf(s-\u003ebuffer + s-\u003elen, s-\u003esize - s-\u003elen, fmt, args);\n 75:\t\t\tif (s-\u003elen + len \u003c s-\u003esize) {\n 76:\t\t\t\ts-\u003elen += len;\n 77:\t\t\t\treturn 0;\n 78:\t\t\t}\n 79:\t\t}\n 80:\t\tseq_buf_set_overflow(s);\n 81:\t\treturn -1;\n 82:\t}\n 83:\t\n 84:\t/\n 85:\t seq_buf_printf - sequence printing of information\n 86:\t * @s: seq_buf descriptor\n 87:\t * @fmt: printf format string\n 88:\t \n 89:\t Writes a printf() format into the sequence buffer.\n 90:\t \n 91:\t Returns: zero on success, -1 on overflow.\n 92:\t /\n 93:\tint seq_buf_printf(struct seq_buf s, const char *fmt, ...)\n 94:\t{\n 95:\t\tva_list ap;\n 96:\t\tint ret;\n 97:\t\n 98:\t\tva_start(ap, fmt);\n 99:\t\tret = seq_buf_vprintf(s, fmt, ap);\n 100:\t\tva_end(ap);\n 101:\t\n 102:\t\treturn ret;\n 103:\t}\n 104:\tEXPORT_SYMBOL_GPL(seq_buf_printf);\n" }
27/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 43797 output: 36 thoughts: 87 Thoughts: Here's my thought process, as it unfolds: Examining Potential Buffer Overflows in `vsnprintf` within a `seq_buf` Context Okay, hold on a second! I'm zeroing in on this line: `vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);`. My brain immediately flags a potential issue, given what I'm seeing with the `seq_buf` structure. Specifically, if `s->len + len` (the current buffer length plus the length of the string to be added) becomes greater than or equal to `s->size` (the total buffer capacity), the code calls `seq_buf_set_overflow(s);`. That's my cue to investigate. What exactly does `seq_buf_set_overflow` do? I'm familiar with the concept and architecture, and I think I vaguely remember where the definition might be, but it's time to confirm and refresh the details. Let's dive into the `include/linux/seq_buf.h` header and see what it reveals.
28/2	2026/09/15 11:10	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 55, "LineCount": 25 } Results: { "Contents": " 55:\t\treturn s-\u003elen \u003e s-\u003esize;\n 56:\t}\n 57:\t\n 58:\tstatic inline void\n 59:\tseq_buf_set_overflow(struct seq_buf s)\n 60:\t{\n 61:\t\ts-\u003elen = s-\u003esize + 1;\n 62:\t}\n 63:\t\n 64:\t/\n 65:\t * How much buffer is left on the seq_buf?\n 66:\t /\n 67:\tstatic inline unsigned int\n 68:\tseq_buf_buffer_left(struct seq_buf s)\n 69:\t{\n 70:\t\tif (seq_buf_has_overflowed(s))\n 71:\t\t\treturn 0;\n 72:\t\n 73:\t\treturn s-\u003esize - s-\u003elen;\n 74:\t}\n 75:\t\n 76:\t/* How much buffer was written? /\n 77:\tstatic inline unsigned int seq_buf_used(struct seq_buf s)\n 78:\t{\n 79:\t\treturn min(s-\u003elen, s-\u003esize);\n" }
29/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 44467 output: 35 thoughts: 646 Thoughts: Analyzing the Fuzzing Potential of This Patch Okay, so I'm looking at this code and trying to figure out if it's worth the fuzzing effort. First, I was thinking about `vsnprintf` and the null termination behavior when buffer lengths and offsets are in play, but that's a bit of a tangent. The key question is whether this patch introduces any new, reachable code that's ripe for fuzzing. I'm checking against the established guidelines for fuzzing targets: memory management, synchronization, BPF, scheduler, networking, VFS, syscalls, refactorings, assertions, and drivers accessible via specific virtual buses or protocols. Right, so this patch is touching `include/linux/fortify-string.h`. Specifically, the fortified `strcat()` implementation. This immediately grabs my attention. Let's see... ```c char strcat(char const POS p, const char q) { const size_t p_size = __member_size(p); if (p_size == SIZE_MAX) return __underlying_strcat(p, q); const size_t p_len = __fortify_strlen(p); const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q); if (p_size <= wanted) fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p); return p; } ``` Okay, so they're changing the fortify string check for `strcat`. Crucially, `strcat` is used all over the kernel. And* when `CONFIG_FORTIFY_SOURCE` is enabled, all callers that have known size use this fortified version. That's a significant surface area. Now, hold on... `fortify_panic()` is a runtime assertion! That's a huge flag for fuzzing, because that's a place to trigger intentional failures. And the `p_size <= wanted` check... Let me check the fortify strlen check in `include/linux/fortify-string.h`.
30/2	2026/09/15 11:10	tool	grepper	0m Args: { "Expression": "__fortify_strlen", "PathPrefix": "include/linux/fortify-string.h" } Results: { "Output": "include/linux/fortify-string.h=169=__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)\n--\ninclude/linux/fortify-string.h-208-\t__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),\t\\\ninclude/linux/fortify-string.h:209:\t\t__builtin_strlen(p), __fortify_strlen(p))\ninclude/linux/fortify-string.h-210-__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\ninclude/linux/fortify-string.h:211:__kernel_size_t __fortify_strlen(const char * const POS p)\ninclude/linux/fortify-string.h-212-{\n--\ninclude/linux/fortify-string.h=363=char strcat(char const POS p, const char *q)\n--\ninclude/linux/fortify-string.h-369-\ninclude/linux/fortify-string.h:370:\tconst size_t p_len = __fortify_strlen(p);\ninclude/linux/fortify-string.h-371-\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n" }
31/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45989 output: 38 thoughts: 26 Thoughts: Here's a summary of my thought process, as if I were the one reading and analyzing that code: Diving into `fortify-string.h` Okay, I'm going to take a look at lines 211-225 in `include/linux/fortify-string.h`. Right, this is where the kernel's string safety mechanisms are defined. I'm expecting to see some macros or functions designed to catch buffer overflows and similar vulnerabilities. I'm hoping to understand how they're implemented, any trade-offs they might make (performance vs. safety), and how they interact with the compiler. I'll be looking for any clever optimizations or potential gotchas that I might have missed in the past. This area is crucial, as any weakness here could be exploited. Let's see what's being done.
32/2	2026/09/15 11:10	tool	read-file	0m Args: { "File": "include/linux/fortify-string.h", "FirstLine": 210, "LineCount": 20 } Results: { "Contents": " 210:\t__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\n 211:\t__kernel_size_t __fortify_strlen(const char * const POS p)\n 212:\t{\n 213:\t\tconst size_t p_size = __member_size(p);\n 214:\t\t__kernel_size_t ret;\n 215:\t\n 216:\t\t/* Give up if we don't know how large p is. /\n 217:\t\tif (p_size == SIZE_MAX)\n 218:\t\t\treturn __underlying_strlen(p);\n 219:\t\tret = strnlen(p, p_size);\n 220:\t\tif (p_size \u003c= ret)\n 221:\t\t\tfortify_panic(FORTIFY_FUNC_strlen, FORTIFY_READ, p_size, ret + 1, ret);\n 222:\t\treturn ret;\n 223:\t}\n 224:\t\n 225:\t/ Defined after fortified strnlen() to reuse it. /\n 226:\textern ssize_t __real_strscpy(char , const char , size_t) __RENAME(sized_strscpy);\n 227:\t__FORTIFY_INLINE ssize_t sized_strscpy(char const POS p, const char * const POS q, size_t size)\n 228:\t{\n 229:\t\t/* Use string size rather than possible enclosing struct size. */\n" }
33/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 46626 output: 32 thoughts: 71 Thoughts: Investigating Synaptics USB Mouse Driver Reachability Okay, so I need to figure out how the `synaptics_usb` driver is handled. My first move is to dive into the source code itself – specifically, the `drivers/input/mouse/synaptics_usb.c` file. Right, let's open that up and get a sense of its structure. Now, a crucial question pops up: Is this driver even reachable in my current configuration? It's not enough that the code exists; it has to be compiled and accessible. So, I need to verify its compilation state. I need to know, is this module built into the kernel, compiled as a module, or disabled entirely? Is it maybe emulated via USB? My go-to here is the `Kconfig` file. I'm going to search for `CONFIG_MOUSE_SYNAPTICS_USB`. That should tell me the dependency chain, and the condition in which this driver gets enabled, or at least how it's handled during configuration. This should provide me with an explicit path as to how this driver is included, if it is at all.
34/2	2026/09/15 11:10	tool	grepper	0m Args: { "Expression": "MOUSE_SYNAPTICS_USB", "PathPrefix": "drivers/input/mouse" } Results: { "Output": "drivers/input/mouse/Kconfig=361=config MOUSE_SYNAPTICS_I2C\n--\ndrivers/input/mouse/Kconfig-378-\ndrivers/input/mouse/Kconfig:379:config MOUSE_SYNAPTICS_USB\ndrivers/input/mouse/Kconfig-380-\ttristate \"Synaptics USB device support\"\n--\ndrivers/input/mouse/Makefile=19=obj-$(CONFIG_MOUSE_SYNAPTICS_I2C)\t+= synaptics_i2c.o\ndrivers/input/mouse/Makefile:20:obj-$(CONFIG_MOUSE_SYNAPTICS_USB)\t+= synaptics_usb.o\ndrivers/input/mouse/Makefile-21-obj-$(CONFIG_MOUSE_VSXXXAA)\t\t+= vsxxxaa.o\n" }
35/2	2026/09/15 11:10	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 47180 output: 35 thoughts: 1124 Thoughts: Analyzing Reachability and Focus for Fuzzing Okay, so I've got this patch in front of me, and my initial thought is: can we actually fuzz this effectively? The goal is to maximize the impact of fuzzing efforts, so I need to assess whether these code changes are reachable and fuzzable. First, let's break down the individual components. The `MOUSE_SYNAPTICS_USB` driver, a USB device, is definitely interesting. Reachable through USB emulation, like syzkaller with dummy_hcd or raw-gadget. Then, there's the audio stuff: `sound/usb/card.c` and `sound/usb/mixer.c`, part of `CONFIG_SND_USB_AUDIO`. This is promising because `snd-usb-audio` is a known fuzzing target, heavily tested with syzkaller via virtual USB emulation. Specifically, I see that `usb_audio_make_longname` in `sound/usb/card.c` has been touched, as well as modifications to `append_ctl_name` and `build_connector_control` in `sound/usb/mixer.c`. This is definitely something I want to investigate. Next up, the networking: `net/sunrpc/addr.c` with the `rpc_sockaddr2uaddr()` function, part of `CONFIG_SUNRPC`. This is core to SUNRPC, NFS/RPC, and thus reachable through network syscalls, sockets, and NFS. Definitely a good target. Then, `net/devlink/dev.c` with `__devlink_compat_running_version`, part of devlink/ethtool networking (`CONFIG_NET`). Reachable via ethtool ioctls on devlink devices. Finally, the `drivers/comedi/drivers/comedi_bond.c`, part of `CONFIG_COMEDI_BOND` and comedi driver. Configurable via ioctls. So, I am confident that these are all executable code that has been modified. Now, let's consider the negative criteria. We don't want to waste effort on changes that aren't actually executable. * No non-kernel code, or docs, or purely decorative logging - Nope, we have actual C code. * No structurally unreachable hardware - While some files touch unreachable hardware (like `drivers/edac/thunderx_edac.c`, `drivers/scsi/bfa/bfa_fcs.c`, `drivers/net/ethernet/intel/i40e/i40e.h`), other files are very much reachable via USB, Networking, ioctls, etc, and work in QEMU / syzkaller. * No unreachable execution paths (e.g., specific to an uninteresting architecture) - The code is for amd64 and reachable during device probe/attach, netlink/ioctl, RPC operations, and general kernel execution. Therefore, since all the reachable code is valid and testable, `WorthFuzzing` is definitively TRUE! Alright, now the key part: FocusSymbols and EnableConfigs. We need to be smart about what we focus on. Remember section 4 of the guidelines: AVOID UBIQUITOUS LIFECYCLE HOT-PATHS. Don't list general, ubiquitous functions like allocators, deallocators, or synchronization primitives. That'll just dilute the fuzzing. Wait, is `strcat` in `include/linux/fortify-string.h` a ubiquitous lifecycle function? Yes, it is. The change is in a static inline function in a header! Let's refer back to Section 4: "HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers)." So we cannot directly target `strcat` because it has no symbol address in the final image, and if we did target callers that use it ubiquitously, it would dilute the fuzzing effort. The question then becomes: What are the non-ubiquitous, specific functions that implement the logic being added or altered, avoiding the inlined helpers like `strcat`? We need to pinpoint the relevant functions that call this inlined code, to improve our coverage and prevent dilution of the fuzzing. We need to go through each changed function in the patch: 1. `sound/usb/card.c`:
36/2	2026/09/15 11:11	tool	read-file	0m Args: { "File": "sound/usb/card.c", "FirstLine": 645, "LineCount": 25 } Results: { "Contents": " 645:\t\tstrim(card-\u003eshortname);\n 646:\t}\n 647:\t\n 648:\tstatic void usb_audio_make_longname(struct usb_device dev,\n 649:\t\t\t\t\t struct snd_usb_audio chip,\n 650:\t\t\t\t\t const struct snd_usb_audio_quirk quirk)\n 651:\t{\n 652:\t\tstruct snd_card card = chip-\u003ecard;\n 653:\t\tconst struct usb_audio_device_name preset;\n 654:\t\tconst char s = NULL;\n 655:\t\tstruct seq_buf sb;\n 656:\t\tchar buf;\n 657:\t\tsize_t size;\n 658:\t\n 659:\t\tpreset = lookup_device_name(chip-\u003eusb_id);\n 660:\t\n 661:\t\t/ shortcut - if any pre-defined string is given, use it /\n 662:\t\tif (preset \u0026\u0026 preset-\u003eprofile_name)\n 663:\t\t\ts = preset-\u003eprofile_name;\n 664:\t\tif (s \u0026\u0026 s) {\n 665:\t\t\tstrscpy(card-\u003elongname, s, sizeof(card-\u003elongname));\n 666:\t\t\treturn;\n 667:\t\t}\n 668:\t\n 669:\t\tif (preset \u0026\u0026 preset-\u003evendor_name)\n" }
37/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 49736 output: 31 thoughts: 19 Thoughts: Here's my take on those thoughts: Tracing the Call Path: usb\_audio\_make\_longname Okay, so I need to understand the flow here. My immediate thought is, "Where exactly does this `usb_audio_make_longname` function get invoked?" I need to see the calling contexts. A function name by itself doesn't tell me much. It could be a critical part of the audio pipeline or some obscure debugging helper. Understanding the call stack is paramount to grasping its significance. Knowing its callers will tell me a lot about its purpose and how it fits into the broader audio driver architecture. Time to dig in and trace those calls.
38/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "usb_audio_make_longname", "PathPrefix": "sound/usb" } Results: { "Output": "sound/usb/card.c=616=static void usb_audio_make_shortname(struct usb_device dev,\n--\nsound/usb/card.c-647-\nsound/usb/card.c:648:static void usb_audio_make_longname(struct usb_device dev,\nsound/usb/card.c-649-\t\t\t\t struct snd_usb_audio chip,\n--\nsound/usb/card.c=758=static int snd_usb_audio_create(struct usb_interface intf,\n--\nsound/usb/card.c-821-\tusb_audio_make_shortname(dev, chip, quirk);\nsound/usb/card.c:822:\tusb_audio_make_longname(dev, chip, quirk);\nsound/usb/card.c-823-\n" }
39/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 50145 output: 30 thoughts: 68 Thoughts: Tracing the `usb_audio_make_longname` Function Okay, so I'm diving into this `usb_audio_make_longname` function. Right, it's a static function, nestled away in `sound/usb/card.c`. That's good to know – static means it's only visible within that file. I remember seeing it called by `snd_usb_audio_create`. Now, the key question is, what calls `snd_usb_audio_create`? That's where the investigation begins! I'll head back over to `sound/usb/card.c` and start retracing the call stack to see where that function is actually invoked, and under what conditions. Understanding the calling context is crucial to grasping the overall behavior.
40/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "snd_usb_audio_create", "PathPrefix": "sound/usb" } Results: { "Output": "sound/usb/card.c=730=static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio chip)\n--\nsound/usb/card.c-757- /\nsound/usb/card.c:758:static int snd_usb_audio_create(struct usb_interface intf,\nsound/usb/card.c-759-\t\t\t\tstruct usb_device dev, int idx,\n--\nsound/usb/card.c-823-\nsound/usb/card.c:824:\tsnd_usb_audio_create_proc(chip);\nsound/usb/card.c-825-\n--\nsound/usb/card.c=972=static int usb_audio_probe(struct usb_interface intf,\n--\nsound/usb/card.c-1030-\t\t\t\tif (enable[i]) {\nsound/usb/card.c:1031:\t\t\t\t\terr = snd_usb_audio_create(intf, dev, i, quirk,\nsound/usb/card.c-1032-\t\t\t\t\t\t\t\t id, \u0026chip);\n--\nsound/usb/proc.c=40=static void proc_audio_usbid_read(struct snd_info_entry entry, struct snd_info_buffer buffer)\n--\nsound/usb/proc.c-48-\nsound/usb/proc.c:49:void snd_usb_audio_create_proc(struct snd_usb_audio chip)\nsound/usb/proc.c-50-{\n--\nsound/usb/proc.h-4-\nsound/usb/proc.h:5:void snd_usb_audio_create_proc(struct snd_usb_audio chip);\nsound/usb/proc.h-6-void snd_usb_proc_pcm_format_add(struct snd_usb_stream stream);\n" }
41/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 50876 output: 36 thoughts: 103 Thoughts: Analyzing USB Audio Probe Okay, so `usb_audio_probe` kicks things off, and I know it ultimately calls `snd_usb_audio_create`. That makes sense. Now I want to understand more about the naming and creation process, so let's see what `usb_audio_make_longname` is doing. I need to dig into the details a little deeper. Right, let's switch gears and go into `sound/usb/mixer.c`. I have a hunch that changes there might be relevant to the device recognition and naming, which is where my investigation is focused. The key is in the mixer controls, of course. Hmm, what functions were changed? Let's refresh my memory of recent updates. Ah, I see: `append_ctl_name` and `build_connector_control`. Those are the prime suspects, dealing directly with control naming and structure. Time to focus in. Let's look closely at lines 2085 to 2105 in `sound/usb/mixer.c`. That should give me the context I need to understand what's going on with the naming and control structure within the USB audio driver.
42/2	2026/09/15 11:11	tool	read-file	0m Args: { "File": "sound/usb/mixer.c", "FirstLine": 2085, "LineCount": 25 } Results: { "Contents": "2085:\t\tcval-\u003eval_type = USB_MIXER_BOOLEAN;\n2086:\t\tcval-\u003echannels = 1; /* report true if any channel is connected /\n2087:\t\tcval-\u003emin = 0;\n2088:\t\tcval-\u003emax = 1;\n2089:\t\tkctl = snd_ctl_new1(\u0026usb_connector_ctl_ro, cval);\n2090:\t\tif (!kctl) {\n2091:\t\t\tusb_audio_err(mixer-\u003echip, \"cannot malloc kcontrol\\n\");\n2092:\t\t\tusb_mixer_elem_info_free(cval);\n2093:\t\t\treturn;\n2094:\t\t}\n2095:\t\n2096:\t\tif (check_mapped_name(map, kctl-\u003eid.name, sizeof(kctl-\u003eid.name)))\n2097:\t\t\tappend_ctl_name(kctl, \" Jack\");\n2098:\t\telse\n2099:\t\t\tget_connector_control_name(mixer, term, is_input, kctl-\u003eid.name,\n2100:\t\t\t\t\t\t sizeof(kctl-\u003eid.name));\n2101:\t\tkctl-\u003eprivate_free = snd_usb_mixer_elem_free;\n2102:\t\tsnd_usb_mixer_add_control(\u0026cval-\u003ehead, kctl);\n2103:\t}\n2104:\t\n2105:\tstatic int parse_clock_source_unit(struct mixer_build state, int unitid,\n2106:\t\t\t\t\t void _ftr)\n2107:\t{\n2108:\t\tstruct uac_clock_source_descriptor hdr = _ftr;\n2109:\t\tstruct usb_mixer_elem_info *cval;\n" }
43/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 51728 output: 29 thoughts: 52 Thoughts: Okay, let's dive into this. I need to take a look at `drivers/input/mouse/synaptics_usb.c`. Specifically, I'm interested in the `synusb_probe` function. The first thing I always do with a probe function is quickly identify if it's static or non-static. The visibility of the probe function changes its scope, and thus its utility. Let's get that identified first.
44/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "synusb_probe", "PathPrefix": "drivers/input/mouse" } Results: { "Output": "drivers/input/mouse/synaptics_usb.c=256=static void synusb_close(struct input_dev dev)\n--\ndrivers/input/mouse/synaptics_usb.c-272-\ndrivers/input/mouse/synaptics_usb.c:273:static int synusb_probe(struct usb_interface intf,\ndrivers/input/mouse/synaptics_usb.c-274-\t\t\tconst struct usb_device_id *id)\n--\ndrivers/input/mouse/synaptics_usb.c=532=static struct usb_driver synusb_driver = {\ndrivers/input/mouse/synaptics_usb.c-533-\t.name\t\t= \"synaptics_usb\",\ndrivers/input/mouse/synaptics_usb.c:534:\t.probe\t\t= synusb_probe,\ndrivers/input/mouse/synaptics_usb.c-535-\t.disconnect\t= synusb_disconnect,\n" }
45/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 52154 output: 41 thoughts: 191 Thoughts: My Initial Thoughts on the Code Okay, so I'm looking at this code and immediately I see `synusb_probe`. That's the probe callback for `synaptics_usb`, which is where I want to start. Now, let's see what else might be relevant. Let's move on to `net/sunrpc/addr.c`. Hmm, `rpc_sockaddr2uaddr` is exported, that's interesting. It's a character pointer function taking a socket address structure and a GFP flag. Worth noting, maybe, depending on context. Next, let's jump over to `net/devlink/dev.c`. I spot `__devlink_compat_running_version` and `devlink_compat_running_version`. Specifically a function `devlink_compat_running_version` is here. That's a void function. Finally, there's something in `drivers/comedi/drivers/comedi_bond.c`. I see `do_dev_config`, which is called by `bonding_attach`. Definitely worth a closer look, let's examine `drivers/comedi/drivers/comedi_bond.c` more thoroughly.
46/2	2026/09/15 11:11	tool	read-file	0m Args: { "File": "drivers/comedi/drivers/comedi_bond.c", "FirstLine": 270, "LineCount": 30 } Results: { "Contents": " 270:\t\n 271:\tstatic int bonding_attach(struct comedi_device dev,\n 272:\t\t\t\t struct comedi_devconfig it)\n 273:\t{\n 274:\t\tstruct comedi_bond_private devpriv;\n 275:\t\tstruct comedi_subdevice s;\n 276:\t\tint ret;\n 277:\t\n 278:\t\tdevpriv = comedi_alloc_devpriv(dev, sizeof(devpriv));\n 279:\t\tif (!devpriv)\n 280:\t\t\treturn -ENOMEM;\n 281:\t\n 282:\t\t/\n 283:\t\t * Setup our bonding from config params.. sets up our private struct..\n 284:\t\t */\n 285:\t\tret = do_dev_config(dev, it);\n 286:\t\tif (ret)\n 287:\t\t\treturn ret;\n 288:\t\n 289:\t\tdev-\u003eboard_name = devpriv-\u003ename;\n 290:\t\n 291:\t\tret = comedi_alloc_subdevices(dev, 1);\n 292:\t\tif (ret)\n 293:\t\t\treturn ret;\n 294:\t\n 295:\t\ts = \u0026dev-\u003esubdevices[0];\n 296:\t\ts-\u003etype = COMEDI_SUBD_DIO;\n 297:\t\ts-\u003esubdev_flags = SDF_READABLE \| SDF_WRITABLE;\n 298:\t\ts-\u003en_chan = devpriv-\u003enchans;\n 299:\t\ts-\u003emaxdata = 1;\n" }
47/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 53073 output: 28 thoughts: 931 Thoughts: Analyzing Potential Focus Symbols for a String Handling Refactor Okay, so I need to figure out the best focus symbols for this refactoring, which replaces `strlcat` with `seq_buf` and `snprintf`. I've already checked a few files like `drm_dp_mst_topology.c`, `sound/pci/ac97/ac97_codec.c`, and some others, but those don't seem like the core of this change. Also, early boot functions like `root_nfs_cat` and `setup_arch` are out, they're too ubiquitous. Let's see, I need to keep in mind the focus symbol criteria: avoid ubiquitous lifecycle hot-paths, target specific feature logic, and handle static inline functions properly. Since `strcat` is inlined, it's not a direct target, so I need to look for callers. But, am I dealing primarily with static inline helpers here? No, this is a multi-file refactoring, so I have to analyze the non-static functions being changed. Okay, the modified C files and the functions that are being changed are: - `sound/usb/card.c` -> `usb_audio_make_longname` (static, called by `snd_usb_audio_create`) - `sound/usb/mixer.c` -> `build_connector_control` (static) / `append_ctl_name` (static) - `drivers/input/mouse/synaptics_usb.c` -> `synusb_probe` - `net/sunrpc/addr.c` -> `rpc_sockaddr2uaddr` - `net/devlink/dev.c` -> `__devlink_compat_running_version` / `devlink_compat_running_version` - `drivers/comedi/drivers/comedi_bond.c` -> `do_dev_config` / `bonding_attach` - `fs/orangefs/orangefs-debugfs.c` -> `orangefs_prepare_debugfs_help_string` Wait, are these static functions even present in vmlinux? Yes, usually they are, unless they're small and get inlined by the compiler. Functions like `usb_audio_make_longname`, `append_ctl_name`, and `do_dev_config` are potential inlining candidates. I need to make sure I don't select something that disappears! I'll check the callers of `usb_audio_make_longname` (`snd_usb_audio_create` or `usb_audio_probe`), I'll look into how `bonding_attach` calls `do_dev_config`, and I'll need to double check the caller for `build_connector_control` in `sound/usb/mixer.c` as well.
48/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "build_connector_control", "PathPrefix": "sound/usb" } Results: { "Output": "sound/usb/mixer.c=2041=static int connector_mixer_resume(struct usb_mixer_elem_list list)\n--\nsound/usb/mixer.c-2049-/ Build a mixer control for a UAC connector control (jack-detect) /\nsound/usb/mixer.c:2050:static void build_connector_control(struct usb_mixer_interface mixer,\nsound/usb/mixer.c-2051-\t\t\t\t const struct usbmix_name_map imap,\n--\nsound/usb/mixer.c=2391=static int parse_audio_input_terminal(struct mixer_build state, int unitid,\n--\nsound/usb/mixer.c-2415-\t uac_v2v3_control_is_readable(bmctls, control))\nsound/usb/mixer.c:2416:\t\tbuild_connector_control(state-\u003emixer, state-\u003emap, \u0026iterm, true);\nsound/usb/mixer.c-2417-\n--\nsound/usb/mixer.c=3265=static int snd_usb_mixer_controls_badd(struct usb_mixer_interface mixer,\n--\nsound/usb/mixer.c-3406-\t\titerm.type = UAC_BIDIR_TERMINAL_HEADSET;\nsound/usb/mixer.c:3407:\t\tbuild_connector_control(mixer, map-\u003emap, \u0026iterm, true);\nsound/usb/mixer.c-3408-\n--\nsound/usb/mixer.c-3412-\t\toterm.type = UAC_BIDIR_TERMINAL_HEADSET;\nsound/usb/mixer.c:3413:\t\tbuild_connector_control(mixer, map-\u003emap, \u0026oterm, false);\nsound/usb/mixer.c-3414-\t}\n--\nsound/usb/mixer.c=3424=static int snd_usb_mixer_controls(struct usb_mixer_interface mixer)\n--\nsound/usb/mixer.c-3487-\t\t\t\t\t\t\t UAC2_TE_CONNECTOR)) {\nsound/usb/mixer.c:3488:\t\t\t\tbuild_connector_control(state.mixer, state.map,\nsound/usb/mixer.c-3489-\t\t\t\t\t\t\t\u0026state.oterm, false);\n--\nsound/usb/mixer.c-3513-\t\t\t\t\t\t\t UAC3_TE_INSERTION)) {\nsound/usb/mixer.c:3514:\t\t\t\tbuild_connector_control(state.mixer, state.map,\nsound/usb/mixer.c-3515-\t\t\t\t\t\t\t\u0026state.oterm, false);\n" }
49/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 55315 output: 36 thoughts: 210 Thoughts: Analyzing Potential Optimization Bottlenecks Okay, so `build_connector_control` gets called all over the place, which probably means the compiler isn't inlining it. That's a good starting point for optimization. Let's see what else might be a problem. First, I should check `rpc_sockaddr2uaddr`. Ah, it's global and non-static, and it's got `EXPORT_SYMBOL_GPL` – that's another function that the compiler probably can't optimize aggressively. Then there's `devlink_compat_running_version` which, again, is global and non-static, so the compiler will have trouble there. Moving on, `synusb_probe` is a probe function and also non-inlined – that's a potential area to investigate further, since probe functions often have some overhead in them. Finally, `bonding_attach` is a driver attach callback in `comedi_bond.c`, so it may have some issues with the same issues, but let's check it regardless. I'll check the config options for each of these: For `synusb_probe`, I need to see what's going on in the Kconfig. I can see it's linked to `CONFIG_MOUSE_SYNAPTICS_USB`, so what does that depend on? Let me scan those lines from 375 to 395 in `drivers/input/mouse/Kconfig` to get the context.
50/2	2026/09/15 11:11	tool	read-file	0m Args: { "File": "drivers/input/mouse/Kconfig", "FirstLine": 375, "LineCount": 20 } Results: { "Contents": " 375:\t\n 376:\t\t To compile this driver as a module, choose M here: the\n 377:\t\t module will be called synaptics_i2c.\n 378:\t\n 379:\tconfig MOUSE_SYNAPTICS_USB\n 380:\t\ttristate \"Synaptics USB device support\"\n 381:\t\tdepends on USB_ARCH_HAS_HCD\n 382:\t\tselect USB\n 383:\t\thelp\n 384:\t\t Say Y here if you want to use a Synaptics USB touchpad or pointing\n 385:\t\t stick.\n 386:\t\n 387:\t\t While these devices emulate an USB mouse by default and can be used\n 388:\t\t with standard usbhid driver, this driver, together with its X.Org\n 389:\t\t counterpart, allows you to fully utilize capabilities of the device.\n 390:\t\t More information can be found at:\n 391:\t\t \u003chttp://jan-steinhoff.de/linux/synaptics-usb.html\u003e\n 392:\t\n 393:\t\t To compile this driver as a module, choose M here: the\n 394:\t\t module will be called synaptics_usb.\n" }
51/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 56216 output: 29 thoughts: 51 Thoughts: Examining USB Dependencies Okay, so I'm looking at `MOUSE_SYNAPTICS_USB` and it's pretty straightforward, depending on `USB_ARCH_HAS_HCD` and, naturally, selecting `USB`. Makes sense; that's the base requirement. My immediate thought, however, is about `SND_USB_AUDIO`. It triggers something similar in my mind. Where does that sit in the dependency chain? Let me just cross-reference the `sound/usb/Kconfig` file to see how those are related and if there are any subtle differences in their dependencies. It's important to be thorough.
52/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "config SND_USB_AUDIO", "PathPrefix": "sound/usb" } Results: { "Output": "sound/usb/Kconfig=11=if SND_USB \u0026\u0026 USB\nsound/usb/Kconfig-12-\nsound/usb/Kconfig:13:config SND_USB_AUDIO\nsound/usb/Kconfig-14-\ttristate \"USB Audio/MIDI driver\"\n--\nsound/usb/Kconfig-27-\nsound/usb/Kconfig:28:config SND_USB_AUDIO_MIDI_V2\nsound/usb/Kconfig-29-\tbool \"MIDI 2.0 support by USB Audio driver\"\n--\nsound/usb/Kconfig-37-\nsound/usb/Kconfig:38:config SND_USB_AUDIO_USE_MEDIA_CONTROLLER\nsound/usb/Kconfig-39-\tbool\n--\nsound/usb/Kconfig=178=config SND_BCD2000\n--\nsound/usb/Kconfig-190-\nsound/usb/Kconfig:191:config SND_USB_AUDIO_QMI\nsound/usb/Kconfig-192-\ttristate \"Qualcomm Audio Offload driver\"\n" }
53/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 56702 output: 29 thoughts: 73 Thoughts: Kernel Configuration Dependencies: A Quick Mental Audit Okay, so I'm looking at these kernel options and tracing their dependencies. SND_USB_AUDIO is clearly reliant on SND_USB, USB, and, implicitly, SND itself – that's straightforward enough. Now, I need to make sure I haven't missed any edge cases. SUNRPC – that's the one I need to consider next. CONFIG_SUNRPC is pretty much a given for any NFS or RPC setup, so no surprises there. Just confirming it's accounted for. Alright, next on the list. What about COMEDI_BOND? Let me double-check its dependencies. Time to go right to the source. I'll need to check the drivers/comedi/Kconfig file to make certain I'm not missing anything critical there. Gotta make sure I'm not accidentally enabling something without its required foundations.
54/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "COMEDI_BOND", "PathPrefix": "drivers/comedi" } Results: { "Output": "drivers/comedi/Kconfig=43=if COMEDI_MISC_DRIVERS\ndrivers/comedi/Kconfig-44-\ndrivers/comedi/Kconfig:45:config COMEDI_BOND\ndrivers/comedi/Kconfig-46-\ttristate \"Comedi device bonding support\"\n--\ndrivers/comedi/drivers/Makefile=8=obj-$(CONFIG_COMEDI_ISADMA)\t\t+= comedi_isadma.o\n--\ndrivers/comedi/drivers/Makefile-10-# Comedi misc drivers\ndrivers/comedi/drivers/Makefile:11:obj-$(CONFIG_COMEDI_BOND)\t\t+= comedi_bond.o\ndrivers/comedi/drivers/Makefile-12-obj-$(CONFIG_COMEDI_TEST)\t\t+= comedi_test.o\n" }
55/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 57213 output: 34 thoughts: 22 Thoughts: Here's my take on those lines from `drivers/comedi/Kconfig`: Examining the Comedi Driver Configuration Okay, let's zero in on lines 40-60 of the `drivers/comedi/Kconfig` file. I'm focusing on this specific block because it's likely defining a specific set of options or dependencies within the Comedi (Control and Measurement Device Interface) framework. Given my expertise, I'm immediately looking for a few key things: What hardware or functionality is this section related to? Are there any sub-options being introduced, or is this a conditional inclusion based on some other kernel configuration? Are there any obvious potential conflicts or dependencies I need to be aware of? Are there any hints about the target platform or use case being described? I'll be particularly attentive to the `depends on` statements and any `select` directives, as they are essential clues to the relationships between features. Knowing the context of this configuration fragment could be critical when troubleshooting device driver issues or adapting the Comedi subsystem for a customized setup. I'm ready to dive into the specifics and decipher the logic here.
56/2	2026/09/15 11:11	tool	read-file	0m Args: { "File": "drivers/comedi/Kconfig", "FirstLine": 40, "LineCount": 25 } Results: { "Contents": " 40:\t\t kernel: saying N will just cause the configurator to skip all\n 41:\t\t the questions about misc non-hardware comedi drivers.\n 42:\t\n 43:\tif COMEDI_MISC_DRIVERS\n 44:\t\n 45:\tconfig COMEDI_BOND\n 46:\t\ttristate \"Comedi device bonding support\"\n 47:\t\tselect COMEDI_KCOMEDILIB\n 48:\t\thelp\n 49:\t\t Enable support for a driver to 'bond' (merge) multiple subdevices\n 50:\t\t from multiple devices together as one.\n 51:\t\n 52:\t\t Currently, it only handles digital I/O subdevices.\n 53:\t\n 54:\t\t To compile this driver as a module, choose M here: the module will be\n 55:\t\t called comedi_bond.\n 56:\t\n 57:\tconfig COMEDI_TEST\n 58:\t\ttristate \"Fake waveform generator support\"\n 59:\t\thelp\n 60:\t\t Enable support for the fake waveform generator.\n 61:\t\t This driver is mainly for testing purposes, but can also be used to\n 62:\t\t generate sample waveforms on systems that don't have data acquisition\n 63:\t\t hardware.\n 64:\t\n" }
57/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 57849 output: 26 thoughts: 103 Thoughts: My Configuration Quandary Okay, so I'm looking at `COMEDI_BOND`. Right off the bat, I know it needs `COMEDI_MISC_DRIVERS` and `COMEDI` to function. That's a given. But my mind is wandering... what's the relationship with `CONFIG_NET` and `CONFIG_NET_DEVLINK`? I'm thinking about network dependencies here. I know `CONFIG_NET` has a hand in enabling devlink – that's the code in `net/devlink/`. That's important to consider. And then my thoughts shift gears... what about `FORTIFY_SOURCE`? Is there some interplay there? I know `CONFIG_FORTIFY_SOURCE` gives us those fortified string helpers. I should probably double-check where that is defined... better to look at the source. I'll take a look at `CONFIG_FORTIFY_SOURCE` within `security/Kconfig`. I'll want to see how the settings are defined.
58/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "config FORTIFY_SOURCE", "PathPrefix": "security" } Results: { "Output": "security/Kconfig.hardening=212=menu \"Bounds checking\"\nsecurity/Kconfig.hardening-213-\nsecurity/Kconfig.hardening:214:config FORTIFY_SOURCE\nsecurity/Kconfig.hardening-215-\tbool \"Harden common str/mem functions against buffer overflows\"\n" }
59/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 58281 output: 30 thoughts: 36 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and rendered in the first person: Investigating the OrangeFS Filesystem Configuration Right, let's see what's happening with the OrangeFS filesystem. My first instinct is to get a handle on its configuration. Specifically, I need to check the relevant Kconfig file. I'm going to look in the `fs/orangefs/Kconfig` directory to find the configuration options. That's where all the fundamental options should be defined. And specifically, I'm thinking I need to find `CONFIG_ORANGEFS_FS`. That's the primary, presumably boolean, flag that enables or disables the entire filesystem. Understanding this option is critical to understanding the OrangeFS build and behavior, particularly if I'm troubleshooting or customizing it. This is a good starting point, and I expect it will likely provide some insight, either direction.
60/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "config ORANGEFS_FS", "PathPrefix": "fs/orangefs" } Results: { "Output": "fs/orangefs/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/orangefs/Kconfig:2:config ORANGEFS_FS\nfs/orangefs/Kconfig-3-\ttristate \"ORANGEFS (Powered by PVFS) support\"\n" }
61/2	2026/09/15 11:11	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 58623 output: 32 thoughts: 52 Thoughts: Investigating DRM_DISPLAY_DP_HELPER Okay, let's dive in. My immediate thought is to check out `DRM_DISPLAY_DP_HELPER`. Where does this come into play? I need to get a handle on its scope. My focus is on the `drivers/gpu/drm/display` area, so I'm thinking the relevant code is probably located there. Specifically, I'm thinking about the file `drm_dp_mst_topology.c`. It makes sense this would be connected since it involves the MST topology, and helper functions often play a role in managing that. Now, my next question is: How is `drm_dp_mst_topology.c` actually compiled and integrated? I need to understand the configuration process. What specific config options are required to get that file included in the build? Knowing that will give me a better understanding of how `DRM_DISPLAY_DP_HELPER` relates to the broader display stack configuration. I need to trace this back.
62/2	2026/09/15 11:11	tool	grepper	0m Args: { "Expression": "drm_dp_mst_topology", "PathPrefix": "drivers/gpu/drm" } Results: { "Output": "\nFull output is too long, showing 500 out of 1531 lines.\nUse more precise expression if possible.\n\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h=644=struct amdgpu_mst_connector {\n--\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h-646-\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h:647:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h-648-\tstruct amdgpu_dm_dp_aux dm_dp_aux;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1167=static int dm_late_init(struct amdgpu_ip_block ip_block)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1217-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1218:static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr mgr)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1219-{\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1269=static void s3_handle_mst(struct drm_device dev, bool suspend)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1273-\tstruct drm_connector_list_iter iter;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1274:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1275-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1289-\t\tif (suspend) {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1290:\t\t\tdrm_dp_mst_topology_mgr_suspend(mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1291-\t\t} else {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1838=static int dm_resume(struct amdgpu_ip_block ip_block)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-2046-\t\telse\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:2047:\t\t\tdrm_dp_mst_topology_queue_probe(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-2048-\t}\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=6109=static int amdgpu_dm_atomic_check(struct drm_device dev,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-6125-\tstruct dm_crtc_state dm_old_crtc_state, dm_new_crtc_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:6126:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:6127:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-6128-\tstruct dsc_mst_fairness_vars vars[MAX_PIPES] = {0};\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h=797=struct amdgpu_dm_connector {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h-825-\t/* DM only /\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:826:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h-827-\tstruct amdgpu_dm_dp_aux dm_dp_aux;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=97=STATIC_IFN_KUNIT int dm_encoder_helper_atomic_check(struct drm_encoder encoder,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-105-\tconst struct drm_display_mode adjusted_mode = \u0026crtc_state-\u003eadjusted_mode;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:106:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-107-\tstruct drm_dp_mst_port mst_port;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:108:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-109-\tenum dc_color_depth color_depth;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=299=int amdgpu_dm_detect_mst_link_for_all_connectors(struct drm_device dev)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-318-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:319:\t\t\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-320-\t\t\tif (ret \u003c 0) {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=1890=STATIC_IFN_KUNIT void amdgpu_dm_connector_destroy(struct drm_connector connector)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-1900-\tif (aconnector-\u003emst_mgr.dev)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:1901:\t\tdrm_dp_mst_topology_mgr_destroy(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-1902-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=348=static bool dp_mst_is_end_device(struct amdgpu_dm_connector aconnector)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-350-\tbool is_end_device = false;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:351:\tstruct drm_dp_mst_topology_mgr mgr = NULL;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-352-\tstruct drm_dp_mst_port port = NULL;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=2831=static int dp_is_mst_connector_show(struct seq_file m, void unused)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-2834-\tstruct amdgpu_dm_connector aconnector = to_amdgpu_dm_connector(connector);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:2835:\tstruct drm_dp_mst_topology_mgr mgr = NULL;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-2836-\tstruct drm_dp_mst_port port = NULL;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=4260=static int trigger_hpd_mst_set(void data, u64 val)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4282-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:4283:\t\t\t\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4284-\t\t\t\tif (ret \u003c 0)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4299-\t\t\tdc_link_dp_receiver_power_ctrl(link, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:4300:\t\t\tdrm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_root-\u003emst_mgr, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4301-\t\t\tlink-\u003emst_stream_alloc_table.stream_count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=311=STATIC_IFN_KUNIT void dm_helpers_construct_old_payload(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:312:\t\t\tstruct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:313:\t\t\tstruct drm_dp_mst_topology_state mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-314-\t\t\tstruct drm_dp_mst_atomic_payload new_payload,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=347=bool dm_helpers_dp_mst_write_payload_allocation_table(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-353-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:354:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-355-\tstruct drm_dp_mst_atomic_payload target_payload, new_payload, old_payload;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:356:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-357-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-368-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:369:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-370-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=419=enum act_return_status dm_helpers_dp_mst_poll_for_allocation_change_trigger(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-423-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:424:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-425-\tint ret;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=446=void dm_helpers_dp_mst_send_payload_allocation(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-450-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:451:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:452:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-453-\tstruct drm_dp_mst_atomic_payload new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-463-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:464:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-465-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=481=void dm_helpers_dp_mst_update_mst_mgr_for_deallocation(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-485-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:486:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:487:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-488-\tstruct drm_dp_mst_atomic_payload new_payload, old_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-497-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:498:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-499-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=601=bool dm_helpers_dp_mst_start_top_mgr(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-622-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:623:\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-624-\tif (ret \u003c 0) {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=636=bool dm_helpers_dp_mst_stop_top_mgr(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-650-\tif (aconnector-\u003emst_mgr.mst_state == true) {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:651:\t\tdrm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-652-\t\tlink-\u003ecur_link_settings.lane_count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h=19=struct drm_dp_mst_atomic_payload;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:20:struct drm_dp_mst_topology_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:21:struct drm_dp_mst_topology_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-22-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h=32=void fill_dc_mst_payload_table_from_drm(struct dc_link link,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-35-\t\t\t\t\t struct dc_dp_mst_stream_allocation_table table);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:36:void dm_helpers_construct_old_payload(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:37:\t\t\t\t struct drm_dp_mst_topology_state mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-38-\t\t\t\t struct drm_dp_mst_atomic_payload new_payload,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=607=STATIC_IFN_KUNIT int dm_dp_mst_atomic_check(struct drm_connector connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-610-\tstruct amdgpu_dm_connector aconnector = to_amdgpu_dm_connector(connector);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:611:\tstruct drm_dp_mst_topology_mgr mst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-612-\tstruct drm_dp_mst_port mst_port = aconnector-\u003emst_output_port;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=659=static struct drm_connector \ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:660:dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-661-\t\t\tstruct drm_dp_mst_port port,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=780=void dm_handle_mst_sideband_msg_ready_event(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:781:\tstruct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-782-\tenum mst_msg_ready_type msg_rdy_type)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=863=EXPORT_IF_KUNIT(dm_handle_mst_sideband_msg_ready_event);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-864-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:865:STATIC_IFN_KUNIT void dm_handle_mst_down_rep_msg_ready(struct drm_dp_mst_topology_mgr mgr)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-866-{\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=869=EXPORT_IF_KUNIT(dm_handle_mst_down_rep_msg_ready);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-870-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:871:static const struct drm_dp_mst_topology_cbs dm_mst_cbs = {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-872-\t.add_connector = dm_dp_add_mst_connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=876=void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager dm,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-898-\taconnector-\u003emst_mgr.cbs = \u0026dm_mst_cbs;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:899:\tdrm_dp_mst_topology_mgr_init(\u0026aconnector-\u003emst_mgr, adev_to_drm(dm-\u003eadev),\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-900-\t\t\t\t \u0026aconnector-\u003edm_dp_aux.aux, 16, 4, aconnector-\u003econnector_id);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1039=static int increase_dsc_bpp(struct drm_atomic_commit state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1040:\t\t\t struct drm_dp_mst_topology_state mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1041-\t\t\t struct dc_link dc_link,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1307=static int compute_mst_dsc_configs_for_link(struct drm_atomic_commit state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1310-\t\t\t\t\t struct dsc_mst_fairness_vars vars,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1311:\t\t\t\t\t struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1312-\t\t\t\t\t int link_vars_start_index)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1316-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1317:\tstruct drm_dp_mst_topology_state mst_state = drm_atomic_get_mst_topology_state(state, mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1318-\tint count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1611=int compute_mst_dsc_configs_for_state(struct drm_atomic_commit state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1618-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1619:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1620-\tstruct resource_pool res_pool;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1681=static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_commit state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1688-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1689:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1690-\tint link_vars_start_index = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=67=struct drm_atomic_commit;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:68:struct drm_dp_mst_topology_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-69-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=79=void dm_handle_mst_sideband_msg_ready_event(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:80:\tstruct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-81-\tenum mst_msg_ready_type msg_rdy_type);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=113=void dm_mst_select_esi_dpcd(u8 dpcd_rev, int dpcd_addr, u8 dpcd_bytes_to_read);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:114:void dm_handle_mst_down_rep_msg_ready(struct drm_dp_mst_topology_mgr mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-115-struct drm_encoder dm_mst_atomic_best_encoder(struct drm_connector connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c=2861=static void dm_test_detect_mst_non_mst_link(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c-2885- The condition short-circuits on a NULL mst_mgr.aux, so the real\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c:2886: * drm_dp_mst_topology_mgr_set_mst() path is never reached.\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c-2887- /\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=2948=static void dm_test_construct_old_payload_empty_list(struct kunit test)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2949-{\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2950:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2951:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2952-\tstruct drm_dp_mst_atomic_payload new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=2984=static void dm_test_construct_old_payload_intervening(struct kunit test)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2985-{\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2986:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2987:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2988-\tstruct drm_dp_mst_atomic_payload new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3033=static void dm_test_write_payload_alloc_table_success(struct kunit test,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3037-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3038:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3039:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3040-\tstruct drm_dp_mst_atomic_payload payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3144=static ssize_t dm_test_act_aux_transfer_fail(struct drm_dp_aux aux,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3154- With a connector-backed link and a failing AUX channel, the non-boot\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3155: * path calls drm_dp_mst_topology_mgr_set_mst(true), which fails to read the\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3156- * DPCD caps and returns a negative error, so the helper returns false.\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3158=static void dm_test_mst_start_top_mgr_set_mst_fail(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3189- \ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3190: * With mst_state set, the helper calls drm_dp_mst_topology_mgr_set_mst(false)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3191- * to disable MST and clears the link lane count. The helper always returns\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3340=static void dm_test_mst_send_payload_alloc_part2_fail(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3343-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3344:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3345:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3346-\tstruct drm_dp_mst_atomic_payload payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3402=static void dm_test_mst_update_mgr_dealloc_success(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3404-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3405:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3406:\tstruct drm_dp_mst_topology_state mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3407-\tstruct drm_dp_mst_atomic_payload payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=499=static void dm_mst_test_retrieve_branch_reads_oui(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-501-\tstruct amdgpu_dm_connector aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:502:\tstruct drm_dp_mst_topology_mgr mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-503-\tstruct drm_dp_mst_branch branch;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=1132=static const struct drm_connector_funcs dm_mst_test_connector_funcs = {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1145- * eDP early return, including dc_link_dp_get_max_link_enc_cap() and\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:1146: * drm_dp_mst_topology_mgr_init(). A fully initialized DRM mode config and\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1147- * connector are required because the topology manager registers a private\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=1150=static void dm_mst_test_initialize_dp_connector_mst(struct kunit test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1195-\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:1196:\tdrm_dp_mst_topology_mgr_destroy(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1197-\tdrm_dp_cec_unregister_connector(\u0026aconnector-\u003edm_dp_aux.aux);\n--\ndrivers/gpu/drm/display/Makefile=8=drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += \\\n--\ndrivers/gpu/drm/display/Makefile-10-\tdrm_dp_helper.o \\\ndrivers/gpu/drm/display/Makefile:11:\tdrm_dp_mst_topology.o\ndrivers/gpu/drm/display/Makefile-12-drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TUNNEL) += \\\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-51-#include \"drm_dp_helper_internal.h\"\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:52:#include \"drm_dp_mst_topology_internal.h\"\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-53-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=61=struct drm_dp_pending_up_req {\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-66-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:67:static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-68-\t\t\t\t char buf);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-69-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:70:static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-71-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:72:static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-73-\t\t\t\t struct drm_dp_mst_port port,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-74-\t\t\t\t int offset, int size, u8 bytes);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:75:static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-76-\t\t\t\t struct drm_dp_mst_port port,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-78-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:79:static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-80-\t\t\t\t struct drm_dp_mst_branch mstb);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=82=static void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:83:drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-84-\t\t\t\t struct drm_dp_mst_branch mstb);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-85-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:86:static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-87-\t\t\t\t\t struct drm_dp_mst_branch mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-88-\t\t\t\t\t struct drm_dp_mst_port port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:89:static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-90-\t\t\t\t guid_t guid);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=93=static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:94:static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr mgr);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-95-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=283=static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr hdr,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-302-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:303:static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-304-\t\t\t\t\t struct drm_dp_sideband_msg_hdr hdr,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=788=static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx msg,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-818-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:819:static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-820-\t\t\t\t\t struct drm_dp_sideband_msg_rx raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1003=drm_dp_sideband_parse_query_stream_enc_status(\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1037-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1038:static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1039-\t\t\t\t\tstruct drm_dp_sideband_msg_rx raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1084=static bool\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1085:drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1086-\t\t\t\t\t struct drm_dp_sideband_msg_rx raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1113-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1114:static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1115-\t\t\t\t\t\t\t struct drm_dp_sideband_msg_rx raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1137-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1138:static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1139-\t\t\t\t struct drm_dp_sideband_msg_rx raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1235=build_query_stream_enc_status(struct drm_dp_sideband_msg_tx msg, u8 stream_id,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1252-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1253:static bool check_txmsg_state(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1254-\t\t\t struct drm_dp_sideband_msg_tx txmsg)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1268=static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1270-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1271:\tstruct drm_dp_mst_topology_mgr mgr = mstb-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1272-\tunsigned long wait_timeout = msecs_to_jiffies(4000);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1487=static void drm_dp_free_mst_port(struct kref kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1507- * ensure that they grab at least one main malloc reference to their MST ports\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1508: * in \u0026drm_dp_mst_topology_cbs.add_connector. This callback is called before\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1509- * there is any chance for \u0026drm_dp_mst_port.malloc_kref to reach 0.\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1543=static noinline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1544:__topology_ref_save(struct drm_dp_mst_topology_mgr mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1545:\t\t struct drm_dp_mst_topology_ref_history history,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1546:\t\t enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1547-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1548:\tstruct drm_dp_mst_topology_ref_entry entry = NULL;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1549-\tdepot_stack_handle_t backtrace;\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1568-\tif (!entry) {\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1569:\t\tstruct drm_dp_mst_topology_ref_entry new;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1570-\t\tint new_len = history-\u003elen + 1;\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1590=topology_ref_history_cmp(const void a, const void b)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1591-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1592:\tconst struct drm_dp_mst_topology_ref_entry entry_a = a, entry_b = b;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1593-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1602=static inline const char \ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1603:topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1604-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1612=__dump_topology_ref_history(struct drm_device drm,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1613:\t\t\t struct drm_dp_mst_topology_ref_history history,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1614-\t\t\t void ptr, const char type_str)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1635-\tfor (i = 0; i \u003c history-\u003elen; i++) {\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1636:\t\tconst struct drm_dp_mst_topology_ref_entry entry =\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1637-\t\t\t\u0026history-\u003eentries[i];\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1670=save_mstb_topology_ref(struct drm_dp_mst_branch mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1671:\t\t enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1672-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1677=save_port_topology_ref(struct drm_dp_mst_port port,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1678:\t\t enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1679-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1683=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1684:topology_ref_history_lock(struct drm_dp_mst_topology_mgr mgr)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1685-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1689=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1690:topology_ref_history_unlock(struct drm_dp_mst_topology_mgr mgr)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1691-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1695=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1696:topology_ref_history_lock(struct drm_dp_mst_topology_mgr mgr) {}\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1697-static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1698:topology_ref_history_unlock(struct drm_dp_mst_topology_mgr mgr) {}\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1699-static inline void\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1707=struct drm_dp_mst_atomic_payload \ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1708:drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state state,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1709-\t\t\t\t struct drm_dp_mst_port port)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1721=static void drm_dp_destroy_mst_branch_device(struct kref kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1724-\t\tcontainer_of(kref, struct drm_dp_mst_branch, topology_kref);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1725:\tstruct drm_dp_mst_topology_mgr mgr = mstb-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1726-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1741-/\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1742: drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1743- * branch device unless it's zero\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1752- * reference to @mstb. If you already have a topology reference to @mstb, you\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1753: * should use drm_dp_mst_topology_get_mstb() instead.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1754- \ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1755- See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1756: * drm_dp_mst_topology_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1757: * drm_dp_mst_topology_put_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1758- \n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1763=static int __must_check\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1764:drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1765-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1780-/*\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1781: drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1782- * branch device\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1787- * you are already guaranteed to have at least one active topology reference\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1788: * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1789- \ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1790- See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1791: * drm_dp_mst_topology_try_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1792: * drm_dp_mst_topology_put_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1793- /\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1794:static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1795-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1806-/*\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1807: drm_dp_mst_topology_put_mstb() - release a topology reference to a branch\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1808- * device\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1814- * See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1815: * drm_dp_mst_topology_try_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1816: * drm_dp_mst_topology_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1817- /\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1818=static void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1819:drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1820-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1830=static void drm_dp_destroy_port(struct kref kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1833-\t\tcontainer_of(kref, struct drm_dp_mst_port, topology_kref);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1834:\tstruct drm_dp_mst_topology_mgr mgr = port-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1835-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1856-/*\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1857: drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1858- * port unless it's zero\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1867- * reference to @port. If you already have a topology reference to @port, you\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1868: * should use drm_dp_mst_topology_get_port() instead.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1869- \ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1870- See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1871: * drm_dp_mst_topology_get_port()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1872: * drm_dp_mst_topology_put_port()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1873- *\n--\n\n" }
63/2	2026/09/15 11:12	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 75127 output: 268 thoughts: 1864 Thoughts: Fuzzing Target Identification: A Focused Approach Okay, so I've been digging into this code, and it looks like `drm_dp_mst_port_add_connector` calls `build_mst_prop_path`, which is related to DP MST. However, syzkaller doesn't typically touch DP MST, so that's a dead end for now. But wait! I've found some much more promising avenues: the USB audio and mixer code (`sound/usb/card.c`, `sound/usb/mixer.c`) are directly reachable through syzkaller's USB fuzzing capabilities, along with Synaptics USB mouse (`drivers/input/mouse/synaptics_usb.c`). Furthermore, RPC via sockets (`net/sunrpc/addr.c`) and devlink functionality via ethtool ioctls (`net/devlink/dev.c`) look like prime targets. Finally, I noticed the Comedi bond driver (`drivers/comedi/drivers/comedi_bond.c`) can be exercised through comedi ioctls. So, let's nail down what functions are relevant here: I see `usb_audio_make_longname` is marked as static, but it could be inlined. I can list both `usb_audio_make_longname` and `snd_usb_audio_create`, since the latter will likely be the actual symbol, if the compiler inlines it! I'm adding `build_connector_control`, `synusb_probe`, `rpc_sockaddr2uaddr`, `devlink_compat_running_version`, and `bonding_attach`, as well. These are directly reachable. Now, I'll identify the required kernel config flags: `SND_USB_AUDIO`, `MOUSE_SYNAPTICS_USB`, `SUNRPC`, `NET`, and `COMEDI` along with `COMEDI_BOND` and `COMEDI_MISC_DRIVERS`. It looks like `COMEDI_MISC_DRIVERS` enables the `COMEDI_BOND` menu. `SND_USB` and `USB` are needed to enable `SND_USB_AUDIO`, while `MOUSE_SYNAPTICS_USB` needs `USB_ARCH_HAS_HCD` and `USB`, and is under `INPUT_MOUSE`, which depends on `INPUT`. I need to confirm these functions are good candidates. Let's make sure that none of these identified symbols are ubiquitous hot paths. Okay, these are specific to the altered code and reachable subsystems: not general memory allocators, page fault handlers, locks, or scheduling primitives. Great, good to go! I will note that `fs/orangefs/orangefs-debugfs.c`, `sound/pci/ac97/ac97_codec.c`, `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c`, `drivers/edac/thunderx_edac.c` and architectures are in the diff, but they are not necessarily immediately reachable. The key reachable areas on amd64 in virtual environments are: - USB audio (`sound/usb/card.c`, `sound/usb/mixer.c`) - USB synaptics mouse (`drivers/input/mouse/synaptics_usb.c`) - SunRPC (`net/sunrpc/addr.c`) - Devlink (`net/devlink/dev.c`) - Comedi bond (`drivers/comedi/drivers/comedi_bond.c`) Now, everything seems thoroughly vetted, and ready to go with `set-results`.
64/2	2026/09/15 11:12	tool	set-results	0m Args: { "EnableConfigs": [ "SND_USB_AUDIO", "MOUSE_SYNAPTICS_USB", "SUNRPC", "COMEDI_BOND", "COMEDI_MISC_DRIVERS", "COMEDI", "FORTIFY_SOURCE" ], "FocusSymbols": [ "usb_audio_make_longname", "snd_usb_audio_create", "build_connector_control", "synusb_probe", "rpc_sockaddr2uaddr", "devlink_compat_running_version", "bonding_attach" ], "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "SND_USB_AUDIO", "MOUSE_SYNAPTICS_USB", "SUNRPC", "COMEDI_BOND", "COMEDI_MISC_DRIVERS", "COMEDI", "FORTIFY_SOURCE" ], "FocusSymbols": [ "usb_audio_make_longname", "snd_usb_audio_create", "build_connector_control", "synusb_probe", "rpc_sockaddr2uaddr", "devlink_compat_running_version", "bonding_attach" ], "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.", "WorthFuzzing": true }
65/1	2026/09/15 11:12	action	If	10m Args: { "WorthFuzzing": true } Results: null
66/2	2026/09/15 11:12	agent	kmsan-evaluator	10m Model: core Args: null Results: { "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 7af038477662f04c34c484a45e1a571280e5f258 Author: syz-cluster <triage@syzkaller.com> Date: Tue Sep 15 11:08:01 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c index 4ec591bde3dfa..21140b44d96e6 100644 --- a/arch/arm/kernel/atags_parse.c +++ b/arch/arm/kernel/atags_parse.c @@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision); static int __init parse_tag_cmdline(const struct tag tag) { #if defined(CONFIG_CMDLINE_EXTEND) - strlcat(default_command_line, " ", COMMAND_LINE_SIZE); - strlcat(default_command_line, tag->u.cmdline.cmdline, - COMMAND_LINE_SIZE); + size_t len = strlen(default_command_line); + + snprintf(default_command_line + len, COMMAND_LINE_SIZE - len, + " %s", tag->u.cmdline.cmdline); #elif defined(CONFIG_CMDLINE_FORCE) pr_warn("Ignoring tag cmdline (using the default kernel command line)\n"); #else diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c index 6fa4a22a58fd6..826396f141b9c 100644 --- a/arch/loongarch/kernel/setup.c +++ b/arch/loongarch/kernel/setup.c @@ -33,6 +33,7 @@ #include <linux/of_address.h> #include <linux/suspend.h> #include <linux/swiotlb.h> +#include <linux/seq_buf.h> #include <asm/addrspace.h> #include <asm/alternative.h> @@ -305,6 +306,8 @@ static void __init fdt_setup(void) static void __init bootcmdline_init(char cmdline_p) { + struct seq_buf s; + / * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line * is trivial - we simply use the built-in command line unconditionally & @@ -315,6 +318,11 @@ static void __init bootcmdline_init(char *cmdline_p) goto out; } + / Initialize seq_buf pointing to boot_command_line / + s.buffer = boot_command_line; + s.size = COMMAND_LINE_SIZE; + s.len = strlen(boot_command_line); + #ifdef CONFIG_OF_FLATTREE / * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system, @@ -323,11 +331,11 @@ static void __init bootcmdline_init(char *cmdline_p) to boot_command_line. / if (initial_boot_params) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + if (s.len) + seq_buf_puts(&s, " "); - if (!strstr(boot_command_line, init_command_line)) - strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE); + if (!strstr(s.buffer, init_command_line)) + seq_buf_puts(&s, init_command_line); goto out; } @@ -338,14 +346,14 @@ static void __init bootcmdline_init(char cmdline_p) CONFIG_CMDLINE_EXTEND is enabled. / if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) && CONFIG_CMDLINE[0]) { - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + seq_buf_puts(&s, " "); + seq_buf_puts(&s, CONFIG_CMDLINE); } / * Use built-in command line if the bootloader command line is empty. / - if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !boot_command_line[0]) + if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !s.len) strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); out: diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 1ae6d0c0e1d67..0d9c2137d6758 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void) static void __init bootcmdline_append(const char s, size_t max) { + size_t len; + int prec; + if (!s[0] \|\| !max) return; - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + len = strlen(boot_command_line); + if (len >= COMMAND_LINE_SIZE - 1) + return; - strlcat(boot_command_line, s, max); + if (len) { + if (COMMAND_LINE_SIZE - len < 3) + return; + + prec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2); + snprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, " %.s", + prec, s); + } else { + prec = min_t(size_t, max, COMMAND_LINE_SIZE - 1); + snprintf(boot_command_line, COMMAND_LINE_SIZE, "%.s", + prec, s); + } } #ifdef CONFIG_OF_EARLY_FLATTREE diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c index d3e17a7a89016..fa3efc82ad874 100644 --- a/arch/parisc/kernel/setup.c +++ b/arch/parisc/kernel/setup.c @@ -17,6 +17,7 @@ #include <linux/init.h> #include <linux/console.h> #include <linux/seq_file.h> +#include <linux/seq_buf.h> #define PCI_DEBUG #include <linux/pci.h> #undef PCI_DEBUG @@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE]; static void __init setup_cmdline(char *cmdline_p) { extern unsigned int boot_args[]; + struct seq_buf s; char p; cmdline_p = command_line; @@ -54,19 +56,21 @@ static void __init setup_cmdline(char cmdline_p) strscpy(boot_command_line, (char )__va(boot_args[1]), COMMAND_LINE_SIZE); + s.buffer = boot_command_line; + s.size = COMMAND_LINE_SIZE; + s.len = strlen(boot_command_line); + /* autodetect console type (if not done by palo yet) / p = boot_command_line; if (!str_has_prefix(p, "console=") && !strstr(p, " console=")) { - strlcat(p, " console=", COMMAND_LINE_SIZE); - if (PAGE0->mem_cons.cl_class == CL_DUPLEX) - strlcat(p, "ttyS0", COMMAND_LINE_SIZE); - else - strlcat(p, "tty0", COMMAND_LINE_SIZE); + seq_buf_printf(&s, " console=%s", + PAGE0->mem_cons.cl_class == CL_DUPLEX ? + "ttyS0" : "tty0"); } / default to use early console / if (!strstr(p, "earlycon")) - strlcat(p, " earlycon=pdc", COMMAND_LINE_SIZE); + seq_buf_printf(&s, " earlycon=pdc"); #ifdef CONFIG_BLK_DEV_INITRD / did palo pass us a ramdisk? / diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index cda6adb9f69c4..c40e0edd7c136 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -916,9 +916,11 @@ void __init setup_arch(char cmdline_p) #else if (builtin_cmdline[0]) { / append boot loader cmdline to builtin / - strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE); - strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE); - strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + char tmp[COMMAND_LINE_SIZE]; + + snprintf(tmp, COMMAND_LINE_SIZE, "%s %s", builtin_cmdline, boot_command_line); + strscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE); + strscpy(boot_command_line, tmp, COMMAND_LINE_SIZE); } #endif builtin_cmdline_added = true; diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c index 8e10ecab4f0dc..a10cfbd04c728 100644 --- a/drivers/comedi/drivers/comedi_bond.c +++ b/drivers/comedi/drivers/comedi_bond.c @@ -39,6 +39,7 @@ #include <linux/module.h> #include <linux/string.h> +#include <linux/seq_buf.h> #include <linux/slab.h> #include <linux/comedi.h> #include <linux/comedi/comedilib.h> @@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) { struct comedi_bond_private devpriv = dev->private; DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS); + struct seq_buf s; int i; memset(&devs_opened, 0, sizeof(devs_opened)); - devpriv->name[0] = 0; + seq_buf_init(&s, devpriv->name, sizeof(devpriv->name)); /* * Loop through all comedi devices specified on the command-line, * building our device list. @@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) } devpriv->devs = devs; devpriv->devs[devpriv->ndevs++] = bdev; - { - /* Append dev:subdev to devpriv->name / - char buf[20]; - - snprintf(buf, sizeof(buf), "%u:%u ", - bdev->minor, bdev->subdev); - strlcat(devpriv->name, buf, - sizeof(devpriv->name)); - } + + / Append dev:subdev to devpriv->name / + seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev); } } @@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it) return -EINVAL; } + seq_buf_str(&s); + return 0; } diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c index 9c0a1e48f96f2..4e3781815b6d7 100644 --- a/drivers/edac/thunderx_edac.c +++ b/drivers/edac/thunderx_edac.c @@ -20,6 +20,7 @@ #include <linux/atomic.h> #include <linux/bitfield.h> #include <linux/circ_buf.h> +#include <linux/seq_buf.h> #include <asm/page.h> @@ -47,12 +48,17 @@ static void decode_register(char str, size_t size, { int ret = 0; + if (size > 0) + str[0] = '\0'; + while (descr->type && descr->mask && descr->descr) { if (reg & descr->mask) { ret = snprintf(str, size, "\n\t%s, %s", descr->type == ERR_CORRECTED ? "Corrected" : "Uncorrected", descr->descr); + if (ret < 0 \|\| ret >= size) + break; str += ret; size -= ret; } @@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void irq_id) while (CIRC_CNT(ocx->com_ring_head, ocx->com_ring_tail, ARRAY_SIZE(ocx->com_err_ctx))) { + struct seq_buf s; + tail = ring_pos(ocx->com_ring_tail, ARRAY_SIZE(ocx->com_err_ctx)); ctx = &ocx->com_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx", - ocx->edac_dev->ctl_name, ctx->reg_com_int); + seq_buf_init(&s, msg, OCX_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx", + ocx->edac_dev->ctl_name, ctx->reg_com_int); decode_register(other, OCX_OTHER_SIZE, ocx_com_errors, ctx->reg_com_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); for (lane = 0; lane < OCX_RX_LANES; lane++) if (ctx->reg_com_int & BIT(lane)) { - snprintf(other, OCX_OTHER_SIZE, - "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx", - lane, ctx->reg_lane_int[lane], - lane, ctx->reg_lane_stat11[lane]); - - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_printf(&s, + "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx", + lane, ctx->reg_lane_int[lane], + lane, ctx->reg_lane_stat11[lane]); decode_register(other, OCX_OTHER_SIZE, ocx_lane_errors, ctx->reg_lane_int[lane]); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); } if (ctx->reg_com_int & OCX_COM_INT_CE) - edac_device_handle_ce(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s)); ocx->com_ring_tail++; } @@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void irq_id) while (CIRC_CNT(ocx->link_ring_head, ocx->link_ring_tail, ARRAY_SIZE(ocx->link_err_ctx))) { + struct seq_buf s; + tail = ring_pos(ocx->link_ring_head, ARRAY_SIZE(ocx->link_err_ctx)); ctx = &ocx->link_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, - "%s: OCX_COM_LINK_INT[%d]: %016llx", - ocx->edac_dev->ctl_name, - ctx->link, ctx->reg_com_link_int); + seq_buf_init(&s, msg, OCX_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: OCX_COM_LINK_INT[%d]: %016llx", + ocx->edac_dev->ctl_name, + ctx->link, ctx->reg_com_link_int); decode_register(other, OCX_OTHER_SIZE, ocx_com_link_errors, ctx->reg_com_link_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&s, other); if (ctx->reg_com_link_int & OCX_COM_LINK_INT_UE) - edac_device_handle_ue(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ue(ocx->edac_dev, 0, 0, seq_buf_str(&s)); else if (ctx->reg_com_link_int & OCX_COM_LINK_INT_CE) - edac_device_handle_ce(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s)); ocx->link_ring_tail++; } @@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void irq_id) while (CIRC_CNT(l2c->ring_head, l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx))) { - snprintf(msg, L2C_MESSAGE_SIZE, - "%s: %s: %016llx, %s: %016llx", - l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, - ctx->reg_ext_name, ctx->reg_ext); + struct seq_buf s; + + tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx)); + ctx = &l2c->err_ctx[tail]; + + seq_buf_init(&s, msg, L2C_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: %s: %016llx, %s: %016llx", + l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, + ctx->reg_ext_name, ctx->reg_ext); decode_register(other, L2C_OTHER_SIZE, l2_errors, ctx->reg_int); - strlcat(msg, other, L2C_MESSAGE_SIZE); + seq_buf_puts(&s, other); if (ctx->reg_int & mask_ue) - edac_device_handle_ue(l2c->edac_dev, 0, 0, msg); + edac_device_handle_ue(l2c->edac_dev, 0, 0, seq_buf_str(&s)); else if (ctx->reg_int & mask_ce) - edac_device_handle_ce(l2c->edac_dev, 0, 0, msg); + edac_device_handle_ce(l2c->edac_dev, 0, 0, seq_buf_str(&s)); l2c->ring_tail++; } diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 7ce9e212770ad..229b5fec44bff 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -29,6 +29,7 @@ #include <linux/kernel.h> #include <linux/random.h> #include <linux/sched.h> +#include <linux/seq_buf.h> #include <linux/seq_file.h> #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) @@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch mstb, char proppath, size_t proppath_size) { + struct seq_buf s; int i; - char temp[8]; - snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id); + seq_buf_init(&s, proppath, proppath_size); + + seq_buf_printf(&s, "mst:%d", mstb->mgr->conn_base_id); for (i = 0; i < (mstb->lct - 1); i++) { int shift = (i % 2) ? 0 : 4; int port_num = (mstb->rad[i / 2] >> shift) & 0xf; - snprintf(temp, sizeof(temp), "-%d", port_num); - strlcat(proppath, temp, proppath_size); + seq_buf_printf(&s, "-%d", port_num); } - snprintf(temp, sizeof(temp), "-%d", pnum); - strlcat(proppath, temp, proppath_size); + seq_buf_printf(&s, "-%d", pnum); + + seq_buf_str(&s); } /* diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c index 0f242db775e1c..548a50f744224 100644 --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c @@ -4,6 +4,7 @@ / #include <linux/debugfs.h> +#include <linux/seq_buf.h> #include <drm/drm_print.h> #include <drm/drm_debugfs.h> @@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf, struct xe_hw_engine hwe; enum xe_hw_engine_id id; char engines[128]; + struct seq_buf s; + const char s_str; - engines[0] = '\0'; + seq_buf_init(&s, engines, sizeof(engines)); if (group < num_groups) { for_each_hw_engine(hwe, gt, id) { @@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file file, char __user buf, u16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe); u32 mask = groups[group].engines[guc_class]; - if (mask & BIT(guc_logical_instance)) { - strlcat(engines, hwe->name, sizeof(engines)); - strlcat(engines, " ", sizeof(engines)); - } + if (mask & BIT(guc_logical_instance)) + seq_buf_printf(&s, "%s ", hwe->name); } - strlcat(engines, "\n", sizeof(engines)); + seq_buf_puts(&s, "\n"); } - return simple_read_from_buffer(buf, count, ppos, engines, strlen(engines)); + s_str = seq_buf_str(&s); + return simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str)); } static const struct file_operations sched_group_engines_fops = { @@ -663,15 +665,15 @@ static ssize_t control_write(struct file file, const char __user buf, size_t c static ssize_t control_read(struct file file, char __user buf, size_t count, loff_t ppos) { char help[128]; + struct seq_buf s; size_t n; - help[0] = '\0'; + seq_buf_init(&s, help, sizeof(help)); for (n = 0; n < ARRAY_SIZE(control_cmds); n++) { - strlcat(help, control_cmds[n].cmd, sizeof(help)); - strlcat(help, "\n", sizeof(help)); + seq_buf_printf(&s, "%s\n", control_cmds[n].cmd); } - return simple_read_from_buffer(buf, count, ppos, help, strlen(help)); + return simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s)); } static const struct file_operations control_ops = { diff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c index 880a0c79148cd..d13d2d6202ee5 100644 --- a/drivers/input/mouse/synaptics_usb.c +++ b/drivers/input/mouse/synaptics_usb.c @@ -41,6 +41,7 @@ #include <linux/usb.h> #include <linux/input.h> #include <linux/usb/input.h> +#include <linux/seq_buf.h> #define USB_VENDOR_ID_SYNAPTICS 0x06cb #define USB_DEVICE_ID_SYNAPTICS_TP 0x0001 /* Synaptics USB TouchPad / @@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface intf, struct input_dev input_dev; unsigned int intf_num = intf->cur_altsetting->desc.bInterfaceNumber; unsigned int altsetting = min(intf->num_altsetting, 1U); + struct seq_buf s; + char path[64]; int error; error = usb_set_interface(udev, intf_num, altsetting); @@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface intf, ep->bInterval); synusb->urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP; + seq_buf_init(&s, synusb->name, sizeof(synusb->name)); + if (udev->manufacturer) - strscpy(synusb->name, udev->manufacturer, - sizeof(synusb->name)); + seq_buf_puts(&s, udev->manufacturer); if (udev->product) { if (udev->manufacturer) - strlcat(synusb->name, " ", sizeof(synusb->name)); - strlcat(synusb->name, udev->product, sizeof(synusb->name)); + seq_buf_puts(&s, " "); + seq_buf_puts(&s, udev->product); } - if (!strlen(synusb->name)) - snprintf(synusb->name, sizeof(synusb->name), - "USB Synaptics Device %04x:%04x", - le16_to_cpu(udev->descriptor.idVendor), - le16_to_cpu(udev->descriptor.idProduct)); + if (!seq_buf_used(&s)) + seq_buf_printf(&s, "USB Synaptics Device %04x:%04x", + le16_to_cpu(udev->descriptor.idVendor), + le16_to_cpu(udev->descriptor.idProduct)); if (synusb->flags & SYNUSB_STICK) - strlcat(synusb->name, " (Stick)", sizeof(synusb->name)); + seq_buf_puts(&s, " (Stick)"); + + seq_buf_str(&s); - usb_make_path(udev, synusb->phys, sizeof(synusb->phys)); - strlcat(synusb->phys, "/input0", sizeof(synusb->phys)); + usb_make_path(udev, path, sizeof(path)); + snprintf(synusb->phys, sizeof(synusb->phys), "%s/input0", path); input_dev->name = synusb->name; input_dev->phys = synusb->phys; diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c index f1241b63aa5ce..bd15eb58fc84f 100644 --- a/drivers/media/dvb-frontends/si2165.c +++ b/drivers/media/dvb-frontends/si2165.c @@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client client) chip_name, rev_char, state->chip_type, state->chip_revcode); - strlcat(state->fe.ops.info.name, chip_name, - sizeof(state->fe.ops.info.name)); + snprintf(state->fe.ops.info.name, sizeof(state->fe.ops.info.name), + "Silicon Labs %s%s%s", + chip_name, + state->has_dvbt ? " DVB-T" : "", + state->has_dvbc ? " DVB-C" : ""); n = 0; - if (state->has_dvbt) { + if (state->has_dvbt) state->fe.ops.delsys[n++] = SYS_DVBT; - strlcat(state->fe.ops.info.name, " DVB-T", - sizeof(state->fe.ops.info.name)); - } - if (state->has_dvbc) { + if (state->has_dvbc) state->fe.ops.delsys[n++] = SYS_DVBC_ANNEX_A; - strlcat(state->fe.ops.info.name, " DVB-C", - sizeof(state->fe.ops.info.name)); - } / return fe pointer / pdata->fe = &state->fe; diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h index 1b6a8fbaa6485..9f792128a0efe 100644 --- a/drivers/net/ethernet/intel/i40e/i40e.h +++ b/drivers/net/ethernet/intel/i40e/i40e.h @@ -1059,19 +1059,26 @@ static inline char i40e_nvm_version_str(struct i40e_hw hw, char buf, size_t len) { char ver[16] = " "; + size_t offset; / Get NVM version / i40e_info_nvm_ver(hw, buf, len); / Append EETrackID if provided / i40e_info_eetrack(hw, &ver[1], sizeof(ver) - 1); - if (strlen(ver) > 1) - strlcat(buf, ver, len); + if (strlen(ver) > 1) { + offset = strlen(buf); + if (offset < len) + snprintf(buf + offset, len - offset, "%s", ver); + } / Append combo image version if provided / i40e_info_civd_ver(hw, &ver[1], sizeof(ver) - 1); - if (strlen(ver) > 1) - strlcat(buf, ver, len); + if (strlen(ver) > 1) { + offset = strlen(buf); + if (offset < len) + snprintf(buf + offset, len - offset, "%s", ver); + } return buf; } diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c index 479b2418ca340..fcc9e9eb57322 100644 --- a/drivers/net/wireless/ath/wil6210/wmi.c +++ b/drivers/net/wireless/ath/wil6210/wmi.c @@ -7,6 +7,7 @@ #include <linux/moduleparam.h> #include <linux/etherdevice.h> #include <linux/if_arp.h> +#include <linux/seq_buf.h> #include "wil6210.h" #include "txrx.h" @@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv wil) static void resume_triggers2string(u32 triggers, char string, int str_size) { - string[0] = '\0'; + struct seq_buf s; + + seq_buf_init(&s, string, str_size); if (!triggers) { - strlcat(string, " UNKNOWN", str_size); - return; - } + seq_buf_puts(&s, " UNKNOWN"); + } else { + if (triggers & WMI_RESUME_TRIGGER_HOST) + seq_buf_puts(&s, " HOST"); - if (triggers & WMI_RESUME_TRIGGER_HOST) - strlcat(string, " HOST", str_size); + if (triggers & WMI_RESUME_TRIGGER_UCAST_RX) + seq_buf_puts(&s, " UCAST_RX"); - if (triggers & WMI_RESUME_TRIGGER_UCAST_RX) - strlcat(string, " UCAST_RX", str_size); + if (triggers & WMI_RESUME_TRIGGER_BCAST_RX) + seq_buf_puts(&s, " BCAST_RX"); - if (triggers & WMI_RESUME_TRIGGER_BCAST_RX) - strlcat(string, " BCAST_RX", str_size); + if (triggers & WMI_RESUME_TRIGGER_WMI_EVT) + seq_buf_puts(&s, " WMI_EVT"); - if (triggers & WMI_RESUME_TRIGGER_WMI_EVT) - strlcat(string, " WMI_EVT", str_size); + if (triggers & WMI_RESUME_TRIGGER_DISCONNECT) + seq_buf_puts(&s, " DISCONNECT"); + } - if (triggers & WMI_RESUME_TRIGGER_DISCONNECT) - strlcat(string, " DISCONNECT", str_size); + seq_buf_str(&s); } int wmi_resume(struct wil6210_priv wil) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c index 22ff326f1924a..2f74a952599ec 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c @@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev, fwreq->n_items = n_fwnames; for (j = 0; j < n_fwnames; j++) { - fwreq->items[j].path = fwnames[j].path; - fwnames[j].path[0] = '\0'; /* check if firmware path is provided by module parameter / if (brcmf_mp_global.firmware_path[0] != '\0') { - strscpy(fwnames[j].path, mp_path, - BRCMF_FW_NAME_LEN); - - if (end != '/') { - strlcat(fwnames[j].path, "/", - BRCMF_FW_NAME_LEN); - } + snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s", + mp_path, (end == '/') ? "" : "/", + mapping_table[i].fw_base, + fwnames[j].extension); + } else { + snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s", + mapping_table[i].fw_base, + fwnames[j].extension); } - strlcat(fwnames[j].path, mapping_table[i].fw_base, - BRCMF_FW_NAME_LEN); - strlcat(fwnames[j].path, fwnames[j].extension, - BRCMF_FW_NAME_LEN); fwreq->items[j].path = fwnames[j].path; } diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index a64afc3ded3d4..311021a83f03e 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char cmdline) const void rng_seed; const void fdt = initial_boot_params; + if (!fdt) + goto handle_cmdline; + node = fdt_path_offset(fdt, "/chosen"); if (node < 0) node = fdt_path_offset(fdt, "/chosen@0"); @@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char cmdline) / #ifdef CONFIG_CMDLINE #if defined(CONFIG_CMDLINE_EXTEND) - strlcat(cmdline, " ", COMMAND_LINE_SIZE); - strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + { + size_t len = strlen(cmdline); + + if (len < COMMAND_LINE_SIZE) + snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE); + } #elif defined(CONFIG_CMDLINE_FORCE) strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); #else diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c index 5ecc9ed4c44db..0d639eec689c0 100644 --- a/drivers/pinctrl/samsung/pinctrl-samsung.c +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c @@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device dev, struct samsung_pinctrl_dr bank = d->pin_banks; for (i = 0; i < d->nr_banks; ++i, ++bank) { - strscpy(node_name, bank->name, sizeof(node_name)); - len = strlcat(node_name, suffix, sizeof(node_name)); + len = snprintf(node_name, sizeof(node_name), "%s%s", bank->name, suffix); if (len >= sizeof(node_name)) { dev_err(dev, "Too long pin bank name '%s', ignoring\n", bank->name); diff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c index 9b57312f43f50..9fe0343c0b321 100644 --- a/drivers/scsi/bfa/bfa_fcs.c +++ b/drivers/scsi/bfa/bfa_fcs.c @@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s fabric) bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model); - /* Model name/number / - strscpy(port_cfg->sym_name.symname, model, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Driver Version / - strlcat(port_cfg->sym_name.symname, driver_info->version, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Host machine name / - strlcat(port_cfg->sym_name.symname, - driver_info->host_machine_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - / * Host OS Info : * If OS Patch Info is not there, do not truncate any bytes from the * OS name string and instead copy the entire OS info string (64 bytes). / if (driver_info->host_os_patch[0] == '\0') { - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); + snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s%s%s%s%s%s%s%s", + model, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR); } else { - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Append host OS Patch Info / - strlcat(port_cfg->sym_name.symname, - driver_info->host_os_patch, - BFA_SYMNAME_MAXLEN); + snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s%s%s%s%s%s%s%s%s", + model, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR, + driver_info->host_os_patch); } / null terminate / @@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s fabric) bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model); - /* Model name/number / - strscpy(port_cfg->node_sym_name.symname, model, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / Driver Version / - strlcat(port_cfg->node_sym_name.symname, (char )driver_info->version, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - /* Host machine name / - strlcat(port_cfg->node_sym_name.symname, - driver_info->host_machine_name, - BFA_SYMNAME_MAXLEN); - strlcat(port_cfg->node_sym_name.symname, - BFA_FCS_PORT_SYMBNAME_SEPARATOR, - BFA_SYMNAME_MAXLEN); - - / null terminate / - port_cfg->node_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0; + / Model name/number, Driver Version, Host machine name / + snprintf(port_cfg->node_sym_name.symname, BFA_SYMNAME_MAXLEN, + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR + "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR, + model, (char )driver_info->version, + driver_info->host_machine_name); } /* diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c index 432612d224374..a28208414aec2 100644 --- a/fs/nfs/nfsroot.c +++ b/fs/nfs/nfsroot.c @@ -173,12 +173,15 @@ static int __init root_nfs_cat(char dest, const char src, const size_t destlen) { size_t len = strlen(dest); + int ret; - if (len && dest[len - 1] != ',') - if (strlcat(dest, ",", destlen) >= destlen) - return -1; + if (len >= destlen) + return -1; + + ret = snprintf(dest + len, destlen - len, "%s%s", + (len && dest[len - 1] != ',') ? "," : "", src); - if (strlcat(dest, src, destlen) >= destlen) + if (ret < 0 \|\| ret >= destlen - len) return -1; return 0; } diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c index 9f94919a6bc62..6e2f9887eab4b 100644 --- a/fs/orangefs/orangefs-debugfs.c +++ b/fs/orangefs/orangefs-debugfs.c @@ -37,6 +37,7 @@ / #include <linux/debugfs.h> #include <linux/slab.h> +#include <linux/seq_buf.h> #include <linux/uaccess.h> @@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot) char client_title = "Client Debug Keywords:\n"; char kernel_title = "Kernel Debug Keywords:\n"; size_t string_size = DEBUG_HELP_STRING_SIZE; - size_t result_size; size_t i; char new; int rc = -EINVAL; + struct seq_buf s; gossip_debug(GOSSIP_UTILS_DEBUG, "%s: start\n", __func__); @@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot) goto out; } + seq_buf_init(&s, new, string_size); + /* - * strlcat(dst, src, size) will append at most - * "size - strlen(dst) - 1" bytes of src onto dst, - * null terminating the result, and return the total - * length of the string it tried to create. - * * We'll just plow through here building our new debug - * help string and let strlcat take care of assuring that + * help string and let seq_buf take care of assuring that * dst doesn't overflow. / - strlcat(new, client_title, string_size); + seq_buf_puts(&s, client_title); if (!at_boot) { @@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot) goto out; } - for (i = 0; i < cdm_element_count; i++) { - strlcat(new, "\t", string_size); - strlcat(new, cdm_array[i].keyword, string_size); - strlcat(new, "\n", string_size); - } + for (i = 0; i < cdm_element_count; i++) + seq_buf_printf(&s, "\t%s\n", cdm_array[i].keyword); } - strlcat(new, "\n", string_size); - strlcat(new, kernel_title, string_size); + seq_buf_puts(&s, "\n"); + seq_buf_puts(&s, kernel_title); - for (i = 0; i < num_kmod_keyword_mask_map; i++) { - strlcat(new, "\t", string_size); - strlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size); - result_size = strlcat(new, "\n", string_size); - } + for (i = 0; i < num_kmod_keyword_mask_map; i++) + seq_buf_printf(&s, "\t%s\n", s_kmod_keyword_mask_map[i].keyword); / See if we tried to put too many bytes into "new"... / - if (result_size >= string_size) { + if (seq_buf_has_overflowed(&s)) { kfree(new); goto out; } @@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot) } else { mutex_lock(&orangefs_help_file_lock); memset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE); - strlcat(debug_help_string, new, string_size); + strscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE); mutex_unlock(&orangefs_help_file_lock); kfree(new); } diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index cf841dc71feff..0b489124bfcb8 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2) char strcat(char * const POS p, const char q) { const size_t p_size = __member_size(p); - const size_t wanted = strlcat(p, q, p_size); + + if (p_size == SIZE_MAX) + return __underlying_strcat(p, q); + + const size_t p_len = __fortify_strlen(p); + const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q); if (p_size <= wanted) fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p); diff --git a/net/devlink/dev.c b/net/devlink/dev.c index 55959b0ff5ab4..987b071345c41 100644 --- a/net/devlink/dev.c +++ b/net/devlink/dev.c @@ -5,6 +5,7 @@ / #include <linux/device.h> +#include <linux/seq_buf.h> #include <net/genetlink.h> #include <net/sock.h> #include "devl_internal.h" @@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink devlink, { struct devlink_info_req req = {}; const struct nlattr nlattr; + struct seq_buf s; struct sk_buff msg; int rem, err; @@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink devlink, if (err) goto free_msg; + seq_buf_init(&s, buf, len); + s.len = strnlen(buf, len); + nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING, (void )msg->data, msg->len, rem) { const struct nlattr kv; @@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink devlink, nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE, nlattr, rem_kv) { - strlcat(buf, nla_data(kv), len); - strlcat(buf, " ", len); + seq_buf_printf(&s, "%s ", (const char )nla_data(kv)); } } free_msg: diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c index 97ff11973c493..a1e4173e5a538 100644 --- a/net/sunrpc/addr.c +++ b/net/sunrpc/addr.c @@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton); / char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags) { - char portbuf[RPCBIND_MAXUADDRPLEN]; char addrbuf[RPCBIND_MAXUADDRLEN]; unsigned short port; + size_t len; switch (sap->sa_family) { case AF_INET: - if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0) + len = rpc_ntop4(sap, addrbuf, sizeof(addrbuf)); + if (len == 0 \|\| len >= sizeof(addrbuf)) return NULL; port = ntohs(((struct sockaddr_in )sap)->sin_port); break; case AF_INET6: - if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0) + len = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)); + if (len == 0 \|\| len >= sizeof(addrbuf)) return NULL; port = ntohs(((struct sockaddr_in6 )sap)->sin6_port); break; @@ -283,11 +285,8 @@ char rpc_sockaddr2uaddr(const struct sockaddr sap, gfp_t gfp_flags) return NULL; } - if (snprintf(portbuf, sizeof(portbuf), - ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf)) - return NULL; - - if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf)) + if (snprintf(addrbuf + len, sizeof(addrbuf) - len, + ".%u.%u", port >> 8, port & 0xff) >= sizeof(addrbuf) - len) return NULL; return kstrdup(addrbuf, gfp_flags); @@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net net, const char uaddr, return 0; } EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr); + diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c index 0bb65be021d97..e145099ee02a9 100644 --- a/sound/pci/ac97/ac97_codec.c +++ b/sound/pci/ac97/ac97_codec.c @@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name, pid = look_for_codec_id(snd_ac97_codec_ids, id); if (pid) { - strlcat(name, " ", maxlen); - strlcat(name, pid->name, maxlen); + int l = strlen(name); + if (pid->mask != 0xffffffff) - sprintf(name + strlen(name), " rev %u", id & ~pid->mask); + snprintf(name + l, maxlen - l, " %s rev %u", pid->name, id & ~pid->mask); + else + snprintf(name + l, maxlen - l, " %s", pid->name); if (ac97 && pid->patch) { if ((modem && (pid->flags & AC97_MODEM_PATCH)) \|\| (! modem && ! (pid->flags & AC97_MODEM_PATCH))) @@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 ac97, unsigned int id, char name, } } else { int l = strlen(name); + snprintf(name + l, maxlen - l, " id %x", id & 0xff); } } diff --git a/sound/usb/card.c b/sound/usb/card.c index 9307da95efbef..bdca8085fca66 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -25,6 +25,7 @@ #include <linux/list.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/seq_buf.h> #include <linux/ctype.h> #include <linux/usb.h> #include <linux/moduleparam.h> @@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device dev, struct snd_card card = chip->card; const struct usb_audio_device_name preset; const char s = NULL; - int len; + struct seq_buf sb; + char buf; + size_t size; preset = lookup_device_name(chip->usb_id); @@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device dev, s = preset->vendor_name; else if (quirk && quirk->vendor_name) s = quirk->vendor_name; - card->longname = 0; + + seq_buf_init(&sb, card->longname, sizeof(card->longname)); + if (s && s) - strscpy(card->longname, s); + seq_buf_puts(&sb, s); else if (dev->manufacturer && dev->manufacturer) - strscpy(card->longname, dev->manufacturer); - - if (card->longname) { - strim(card->longname); - if (card->longname) - strlcat(card->longname, " ", sizeof(card->longname)); + seq_buf_puts(&sb, dev->manufacturer); + + if (seq_buf_used(&sb)) { + char trimmed; + + seq_buf_str(&sb); + trimmed = strim(card->longname); + if (trimmed != card->longname) + memmove(card->longname, trimmed, strlen(trimmed) + 1); + sb.len = strlen(card->longname); + if (sb.len) + seq_buf_putc(&sb, ' '); } - strlcat(card->longname, card->shortname, sizeof(card->longname)); + seq_buf_puts(&sb, card->shortname); - len = strlcat(card->longname, " at ", sizeof(card->longname)); + seq_buf_puts(&sb, " at "); - if (len < sizeof(card->longname)) - usb_make_path(dev, card->longname + len, sizeof(card->longname) - len); + size = seq_buf_get_buf(&sb, &buf); + if (size > 0) { + int path_len = usb_make_path(dev, buf, size); + + if (path_len >= 0) + seq_buf_commit(&sb, path_len); + else + seq_buf_set_overflow(&sb); + } switch (snd_usb_get_speed(dev)) { case USB_SPEED_LOW: - strlcat(card->longname, ", low speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", low speed"); break; case USB_SPEED_FULL: - strlcat(card->longname, ", full speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", full speed"); break; case USB_SPEED_HIGH: - strlcat(card->longname, ", high speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", high speed"); break; case USB_SPEED_SUPER: - strlcat(card->longname, ", super speed", sizeof(card->longname)); + seq_buf_puts(&sb, ", super speed"); break; case USB_SPEED_SUPER_PLUS: - strlcat(card->longname, ", super speed plus", sizeof(card->longname)); + seq_buf_puts(&sb, ", super speed plus"); break; default: break; } + + seq_buf_str(&sb); } static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio chip) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index ecaa8bc08d7ca..f64ecad4e77ea 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new snd_usb_feature_unit_ctl = &usb_feature_unit_ctl; / static size_t append_ctl_name(struct snd_kcontrol kctl, const char str) { - return strlcat(kctl->id.name, str, sizeof(kctl->id.name)); + size_t len = strlen(kctl->id.name); + + if (len >= sizeof(kctl->id.name)) + return len + strlen(str); + return len + snprintf(kctl->id.name + len, sizeof(kctl->id.name) - len, "%s", str); } /* @@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer, } if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name))) - strlcat(kctl->id.name, " Jack", sizeof(kctl->id.name)); + append_ctl_name(kctl, " Jack"); else get_connector_control_name(mixer, term, is_input, kctl->id.name, sizeof(kctl->id.name));
67/3	2026/09/15 11:12	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19908 output: 37 thoughts: 644 Thoughts: Analyzing the `strlcat` Deprecation Patch Okay, so this patch is aimed at removing `strlcat` from the kernel, a good move overall. The general approach seems to be replacing it with safer alternatives like `snprintf`, `seq_buf`, and `strscpy`. Now, my job is to make sure this is done correctly and doesn't introduce any new vulnerabilities, like uninitialized memory issues or information leaks. Let's go through these changes file by file. First up, `arch/arm/kernel/atags_parse.c`. They've replaced the `strlcat` calls with `snprintf`. Seems straightforward: calculating the current length of `default_command_line` and then using `snprintf` to append the new content. Looks safe, as long as `COMMAND_LINE_SIZE` is handled properly. Next, `arch/loongarch/kernel/setup.c` introduces a `seq_buf`. Smart, using a `seq_buf` is a much cleaner way to build a string, it's safer. `s.buffer = boot_command_line; s.size = COMMAND_LINE_SIZE; s.len = strlen(boot_command_line);` looks fine. In `arch/mips/kernel/setup.c` and `arch/parisc/kernel/setup.c`, again, they're using `snprintf` and `seq_buf` respectively, similar to the previous cases. Looks good; consistent application of the replacement strategy. Now, `arch/x86/kernel/setup.c` has a slightly more complex approach. They're using `snprintf` to build a temporary buffer (`tmp`) and then copying it back to the target strings (`builtin_cmdline` and `boot_command_line`) using `strscpy`. The temporary buffer is crucial here; `snprintf` will null-terminate it, which makes `strscpy` safe. It's a bit more overhead, but it's a valid way to handle this. Okay, now for `drivers/comedi/drivers/comedi_bond.c`. They've replaced `devpriv->name[0] = 0;` with `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));`. Wait, before, it was null-terminating the `devpriv->name` string. However, they now initialize a `seq_buf` struct to point at `devpriv->name`. Before I can make a decision, let me check the memory allocation for `devpriv`. I'm concerned about the initialization, or lack thereof. Let's go check the allocation of `devpriv` in this file. It is a critical step, but not yet complete.
68/3	2026/09/15 11:12	tool	grepper	0m Args: { "Expression": "devpriv = ", "PathPrefix": "drivers/comedi/drivers/comedi_bond.c" } Results: { "Output": "drivers/comedi/drivers/comedi_bond.c=62=static int bonding_dio_insn_bits(struct comedi_device dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-65-{\ndrivers/comedi/drivers/comedi_bond.c:66:\tstruct comedi_bond_private devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-67-\tunsigned int n_left, n_done, base_chan;\n--\ndrivers/comedi/drivers/comedi_bond.c=125=static int bonding_dio_insn_config(struct comedi_device dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-128-{\ndrivers/comedi/drivers/comedi_bond.c:129:\tstruct comedi_bond_private devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-130-\tunsigned int chan = CR_CHAN(insn-\u003echanspec);\n--\ndrivers/comedi/drivers/comedi_bond.c=170=static int do_dev_config(struct comedi_device dev, struct comedi_devconfig it)\ndrivers/comedi/drivers/comedi_bond.c-171-{\ndrivers/comedi/drivers/comedi_bond.c:172:\tstruct comedi_bond_private devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-173-\tDECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);\n--\ndrivers/comedi/drivers/comedi_bond.c=271=static int bonding_attach(struct comedi_device dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-277-\ndrivers/comedi/drivers/comedi_bond.c:278:\tdevpriv = comedi_alloc_devpriv(dev, sizeof(devpriv));\ndrivers/comedi/drivers/comedi_bond.c-279-\tif (!devpriv)\n--\ndrivers/comedi/drivers/comedi_bond.c=312=static void bonding_detach(struct comedi_device dev)\ndrivers/comedi/drivers/comedi_bond.c-313-{\ndrivers/comedi/drivers/comedi_bond.c:314:\tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-315-\n" }
69/3	2026/09/15 11:12	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 21824 output: 34 thoughts: 106 Thoughts: Analyzing the Memory Allocation and Initialization Okay, so `comedi_alloc_devpriv` is using `kzalloc`. That's good; clear, zeroed memory is always a solid starting point. Now, looking at this next line, `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));` I see it's initializing `s`. Specifically, `s.buffer` is set to point to `devpriv->name`, which makes sense, given the intention to use it as a string buffer. It also sets up `s.size` to the size of `devpriv->name`, and initializes `s.len` and `s.readpos` to zero. That sets up the buffer, its capacity, and the current status. But the part I need to grok here is `seq_buf_str(&s)`. I remember reading the seq files documentation, but just to be sure, it looks like I need to dive into the definition of `seq_buf_str` to truly understand what's happening.
70/3	2026/09/15 11:13	tool	grepper	0m Args: { "Expression": "seq_buf_str", "PathPrefix": "include/linux/seq_buf.h" } Results: { "Output": "include/linux/seq_buf.h=77=static inline unsigned int seq_buf_used(struct seq_buf s)\n--\ninclude/linux/seq_buf.h-82-/\ninclude/linux/seq_buf.h:83: seq_buf_str - get NUL-terminated C string from seq_buf\ninclude/linux/seq_buf.h-84- * @s: the seq_buf handle\n--\ninclude/linux/seq_buf.h-97- /\ninclude/linux/seq_buf.h:98:static inline const char seq_buf_str(struct seq_buf *s)\ninclude/linux/seq_buf.h-99-{\n" }
71/3	2026/09/15 11:13	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 22369 output: 36 thoughts: 24 Thoughts: Here's a first-person summary, tailored as requested: Diving into `seq_buf.h`'s Core Okay, time to get my hands dirty. Let's pull up `include/linux/seq_buf.h` and focus in on lines 80 through 120. I need to refresh my memory on how this buffer is handled within the kernel and its critical characteristics. I'm going to have to carefully consider it; I need to remember the intricacies of its design. It's used for efficient, sequential writes to a character buffer, right? I need to think about how this affects the user space. Does this mean it's primarily designed for fast logging or trace information, where sequential access is the norm? Is the design optimal or are there things I could see that I would change if I were working on a system where this was a bottleneck? I'm particularly interested in memory management nuances. What's the allocation strategy? Is it a statically sized buffer, or does it grow dynamically? If dynamic, what's the growth mechanism, and how does that impact performance and fragmentation over time? I want to see if the implementation handles potential race conditions, concurrent access, or interrupt contexts correctly. This is important to ensure data integrity and avoid any potential kernel panics. My goal here is to analyze the trade-offs the developers made; does it prioritize speed, memory usage, or something else entirely? Also, are there opportunities for optimization? Let's get to it.
72/3	2026/09/15 11:13	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 80, "LineCount": 40 } Results: { "Contents": " 80:\t}\n 81:\t\n 82:\t/*\n 83:\t seq_buf_str - get NUL-terminated C string from seq_buf\n 84:\t * @s: the seq_buf handle\n 85:\t \n 86:\t This makes sure that the buffer in @s is NUL-terminated and\n 87:\t * safe to read as a string.\n 88:\t \n 89:\t Note, if this is called when the buffer has overflowed, then\n 90:\t * the last byte of the buffer is zeroed, and the len will still\n 91:\t * point passed it.\n 92:\t \n 93:\t After this function is called, s-\u003ebuffer is safe to use\n 94:\t * in string operations.\n 95:\t \n 96:\t Returns: @s-\u003ebuf after making sure it is terminated.\n 97:\t /\n 98:\tstatic inline const char seq_buf_str(struct seq_buf s)\n 99:\t{\n 100:\t\tif (WARN_ON(s-\u003esize == 0))\n 101:\t\t\treturn \"\";\n 102:\t\n 103:\t\tif (seq_buf_buffer_left(s))\n 104:\t\t\ts-\u003ebuffer[s-\u003elen] = 0;\n 105:\t\telse\n 106:\t\t\ts-\u003ebuffer[s-\u003esize - 1] = 0;\n 107:\t\n 108:\t\treturn s-\u003ebuffer;\n 109:\t}\n 110:\t\n 111:\t/\n 112:\t seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t \n 116:\t Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t /\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf s, char **bufp)\n" }
73/3	2026/09/15 11:13	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 23316 output: 34 thoughts: 408 Thoughts: My Line of Reasoning Okay, so `seq_buf_str` is responsible for null-terminating the buffer. Wait a minute... didn't I see something earlier that initialized the string as empty? Ah, yes, `devpriv->name[0] = 0;`. That seems redundant, doesn't it? If the loop doesn't execute, or if `seq_buf_str(&s)` is called at the end without printing anything, what's actually in `devpriv->name`? Let me think this through: `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));` sets `s.len` to zero at the beginning. Then, if nothing is printed to the buffer, `seq_buf_str(&s)` does indeed set `s->buffer[0] = 0`, so `devpriv->name[0] = 0`. It is null-terminated. And, since `devpriv` was `kzalloc`'d, it should already be zeroed. Good, it's consistent. Just to be thorough, I should look at related code. Let's see... what about the other files? Right, `drivers/edac/thunderx_edac.c`: ```c static void decode_register(char *str, size_t size, ... + if (size > 0) + str[0] = '\0'; ``` That's pretty explicit: if the size is greater than zero, then `str[0] = '\0'`, setting the first character to null which also initializes the string to be empty. And then I see: ```c - snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx", - ocx->edac_dev->ctl_name, ctx->reg_com_int); + seq_buf_init(&s, msg, OCX_MESSAGE_SIZE); + + seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx", + ocx->edac_dev->ctl_name, ctx->reg_com_int); ``` Here, they're using `seq_buf` rather than `snprintf`. I'll quickly double-check where `msg` is defined. Is it a stack buffer or an array? Let's check `drivers/edac/thunderx_edac.c`.
74/3	2026/09/15 11:13	tool	grepper	0m Error: no matches Args: { "Expression": "msg\\[", "PathPrefix": "drivers/edac/thunderx_edac.c" } Results: { "error": "no matches" }
75/3	2026/09/15 11:13	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 24332 output: 41 thoughts: 26 Thoughts: Here's a summary of my thought process, as if I were the one thinking it: Diving into ThunderX EDAC Okay, time to get to the heart of the matter. I need to zero in on the EDAC driver for the ThunderX platform. The specific area I'm focusing on right now is around line 1115 in `drivers/edac/thunderx_edac.c`. I have a feeling something interesting, or potentially problematic, is going on in that section of the code. Let's see what the context is. I'll take a close look at the surrounding lines to understand the logic flow and identify the key functions or data structures being used. Hopefully, this will lead me to the root cause, or at least a clearer understanding of the issue I'm investigating. I need to quickly recall the expected behavior of the ThunderX EDAC controller and how it's supposed to handle ECC errors. Let's see what secrets this section of code is hiding.
76/3	2026/09/15 11:13	tool	read-file	0m Args: { "File": "drivers/edac/thunderx_edac.c", "FirstLine": 1110, "LineCount": 40 } Results: { "Contents": "1110:\t\tunsigned long tail;\n1111:\t\tstruct ocx_com_err_ctx ctx;\n1112:\t\tint lane;\n1113:\t\tchar msg;\n1114:\t\tchar *other;\n1115:\t\n1116:\t\tmsg = kmalloc(OCX_MESSAGE_SIZE, GFP_KERNEL);\n1117:\t\tother = kmalloc(OCX_OTHER_SIZE, GFP_KERNEL);\n1118:\t\n1119:\t\tif (!msg \|\| !other)\n1120:\t\t\tgoto err_free;\n1121:\t\n1122:\t\twhile (CIRC_CNT(ocx-\u003ecom_ring_head, ocx-\u003ecom_ring_tail,\n1123:\t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx))) {\n1124:\t\t\tstruct seq_buf s;\n1125:\t\n1126:\t\t\ttail = ring_pos(ocx-\u003ecom_ring_tail,\n1127:\t\t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx));\n1128:\t\t\tctx = \u0026ocx-\u003ecom_err_ctx[tail];\n1129:\t\n1130:\t\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n1131:\t\n1132:\t\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_INT: %016llx\",\n1133:\t\t\t\t ocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n1134:\t\n1135:\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n1136:\t\t\t\t\tocx_com_errors, ctx-\u003ereg_com_int);\n1137:\t\n1138:\t\t\tseq_buf_puts(\u0026s, other);\n1139:\t\n1140:\t\t\tfor (lane = 0; lane \u003c OCX_RX_LANES; lane++)\n1141:\t\t\t\tif (ctx-\u003ereg_com_int \u0026 BIT(lane)) {\n1142:\t\t\t\t\tseq_buf_printf(\u0026s,\n1143:\t\t\t\t\t\t \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n1144:\t\t\t\t\t\t lane, ctx-\u003ereg_lane_int[lane],\n1145:\t\t\t\t\t\t lane, ctx-\u003ereg_lane_stat11[lane]);\n1146:\t\n1147:\t\t\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n1148:\t\t\t\t\t\t\tocx_lane_errors,\n1149:\t\t\t\t\t\t\tctx-\u003ereg_lane_int[lane]);\n" }
77/3	2026/09/15 11:13	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25307 output: 34 thoughts: 1902 Thoughts: Code Review: A Deep Dive into Memory Safety and String Handling Okay, let's break this down. First, the initial change to `decode_register` caught my eye. The addition of `str[0] = '\0'` at the beginning, conditional on `size > 0`, immediately flags a potential issue. Before, if `decode_register` didn't write anything, `other` would have contained garbage, leading to a read of uninitialized memory by `strlcat`. The patch is clearly fixing a vulnerability here by ensuring a null terminator, making `other` a valid empty string even when no description matches are found. Good catch. Moving on, the `drm_dp_mst_topology.c` change seems straightforward. Replacing `snprintf` and `strlcat` with the `seq_buf` API is a standard approach to avoid buffer overflows. The use of `seq_buf_str` to guarantee null-termination at the end gives me peace of mind here. It seems the goal here is to construct a path string, and this is a much safer, cleaner way to do it, and avoids any potential overflow by checking the capacity of the buffer. Now, we get to the juicy part – `xe_gt_sriov_pf_debugfs.c`. This is where it gets interesting. `engines` is a stack buffer. That's my first red flag. The code then initializes a `seq_buf` on this stack buffer without initializing the buffer itself. This is a problem! The critical question is, "What happens if `group >= num_groups`?". If the condition is false, the code jumps directly to `seq_buf_str(&s)`. `seq_buf_str` itself checks for the edge case, which is a good thing, and sets the first byte to `0` if it's the beginning of the string, which it would be. That ensures an empty string is returned, preventing any uninitialized reads during the `simple_read_from_buffer` call. The more significant potential issue is the scenario if `group < num_groups`. The loop potentially writes to the `seq_buf`, but `seq_buf_printf` and `seq_buf_puts` are crucial here. I need to dive deeper into those to ensure they handle potential overflows correctly. The code calls `s_str = seq_buf_str(&s)` which returns a pointer to the now-populated buffer and copies `strlen(s_str)` bytes to the user. I need to make sure the loop never writes past the end of the buffer, or the `simple_read_from_buffer` will have a bad time. Then, `seq_buf_str` can potentially truncate the buffer (sets the null terminator at `s->size -1` if `seq_buf_buffer_left` returns false) and ensures the string can be read from userspace. My assumption is that the `seq_buf` implementation handles overflows gracefully by potentially truncating the buffer, which would prevent writing past the end of it. Overall, the initial change fixes a definite memory safety issue. The second is safe and clean, and is exactly what I would recommend. The last needs a little more digging, but it seems safe because of the null termination and buffer management provided by `seq_buf`. I'd still want to confirm the overflow handling within `seq_buf_printf`, and `seq_buf_puts` to be absolutely certain, but on the surface, this looks good.
78/3	2026/09/15 11:14	tool	grepper	0m Args: { "Expression": "seq_buf_puts", "PathPrefix": "include/linux/seq_buf.h" } Results: { "Output": "include/linux/seq_buf.h=174=extern int seq_buf_to_user(struct seq_buf s, char __user ubuf,\ninclude/linux/seq_buf.h-175-\t\t\t size_t start, int cnt);\ninclude/linux/seq_buf.h:176:extern int seq_buf_puts(struct seq_buf s, const char str);\ninclude/linux/seq_buf.h-177-extern int seq_buf_putc(struct seq_buf *s, unsigned char c);\n" }
79/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 28150 output: 32 thoughts: 35 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Diving into `lib/seq_buf.c` for Buffer Write Mechanics Right, let's get down to brass tacks. I need to refresh my understanding of how the `seq_buf` library handles output. I'm specifically interested in the low-level details of writing to the buffers. That means I'm going to jump into `lib/seq_buf.c`. My primary targets are the `seq_buf_printf` and `seq_buf_puts` functions. I want to see precisely how they manage the buffer writes. Are they doing direct memory access? Are there internal locks? How does error handling work in a write failure? Understanding these mechanics is crucial to grasp how the entire `seq_buf` system functions and to identify potential bottlenecks or subtle bugs down the line, especially in high-concurrency or resource-constrained scenarios. Time to see what the implementation details reveal.
80/3	2026/09/15 11:14	tool	grepper	0m Args: { "Expression": "seq_buf_puts", "PathPrefix": "lib/seq_buf.c" } Results: { "Output": "lib/seq_buf.c=154=int seq_buf_bprintf(struct seq_buf s, const char fmt, const u32 binary)\n--\nlib/seq_buf.c-173-/\nlib/seq_buf.c:174: seq_buf_puts - sequence printing of simple string\nlib/seq_buf.c-175- * @s: seq_buf descriptor\n--\nlib/seq_buf.c-181- /\nlib/seq_buf.c:182:int seq_buf_puts(struct seq_buf s, const char *str)\nlib/seq_buf.c-183-{\n--\nlib/seq_buf.c-199-}\nlib/seq_buf.c:200:EXPORT_SYMBOL_GPL(seq_buf_puts);\nlib/seq_buf.c-201-\n" }
81/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 28655 output: 35 thoughts: 21 Thoughts: Okay, let's dive into this. I'm going to pull up lines 182 through 205 of `lib/seq_buf.c`. I need to get a clear picture of what's happening within that specific segment. My focus is probably going to be around the functions or data structures defined in this area, depending on my current task or what I'm looking to optimize. I'll be looking for potential memory management issues, concurrency implications, or simply the overall flow of data within this buffer. I expect it contains some essential part to the buffer management code. Let's see what's what.
82/3	2026/09/15 11:14	tool	read-file	0m Args: { "File": "lib/seq_buf.c", "FirstLine": 180, "LineCount": 30 } Results: { "Contents": " 180:\t * Returns: zero on success, -1 on overflow.\n 181:\t /\n 182:\tint seq_buf_puts(struct seq_buf s, const char str)\n 183:\t{\n 184:\t\tsize_t len = strlen(str);\n 185:\t\n 186:\t\tWARN_ON(s-\u003esize == 0);\n 187:\t\n 188:\t\t/ Add 1 to len for the trailing null byte which must be there /\n 189:\t\tlen += 1;\n 190:\t\n 191:\t\tif (seq_buf_can_fit(s, len)) {\n 192:\t\t\tmemcpy(s-\u003ebuffer + s-\u003elen, str, len);\n 193:\t\t\t/ Don't count the trailing null byte against the capacity /\n 194:\t\t\ts-\u003elen += len - 1;\n 195:\t\t\treturn 0;\n 196:\t\t}\n 197:\t\tseq_buf_set_overflow(s);\n 198:\t\treturn -1;\n 199:\t}\n 200:\tEXPORT_SYMBOL_GPL(seq_buf_puts);\n 201:\t\n 202:\t/\n 203:\t seq_buf_putc - sequence printing of simple character\n 204:\t * @s: seq_buf descriptor\n 205:\t * @c: simple character to record\n 206:\t \n 207:\t Copy a single character into the sequence buffer.\n 208:\t \n 209:\t Returns: zero on success, -1 on overflow.\n" }
83/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 29280 output: 32 thoughts: 72 Thoughts: Okay, let's break this down. Investigating `seq_buf_puts` and its Potential Implications for `seq_buf_printf` Right, so `seq_buf_puts` is moving data, specifically a length of `len` bytes including the null terminator, into the buffer. Critically, it then increments `s->len` by `len - 1`. That makes sense: you copy the full string including the null, and `s->len` then points to the end of the data portion, not past the null. I have to keep that null-termination in mind, always. But now I'm wondering about the implications for `seq_buf_printf`. Since I'm building strings, `printf`-like operations are key, and I'd bet the buffer is being built up for other reasons. I need to understand how that function handles things. It's obviously going to be more complex than a straight memory copy. I'll need to check the code for `seq_buf_printf`, and the best place for it is in `lib/seq_buf.c`.
84/3	2026/09/15 11:14	tool	grepper	0m Args: { "Expression": "seq_buf_printf", "PathPrefix": "lib/seq_buf.c" } Results: { "Output": "lib/seq_buf.c=67=int seq_buf_vprintf(struct seq_buf s, const char fmt, va_list args)\n--\nlib/seq_buf.c-84-/*\nlib/seq_buf.c:85: seq_buf_printf - sequence printing of information\nlib/seq_buf.c-86- * @s: seq_buf descriptor\n--\nlib/seq_buf.c-92- /\nlib/seq_buf.c:93:int seq_buf_printf(struct seq_buf s, const char fmt, ...)\nlib/seq_buf.c-94-{\n--\nlib/seq_buf.c-103-}\nlib/seq_buf.c:104:EXPORT_SYMBOL_GPL(seq_buf_printf);\nlib/seq_buf.c-105-\n--\nlib/seq_buf.c=403=int seq_buf_hex_dump(struct seq_buf s, const char *prefix_str, int prefix_type,\n--\nlib/seq_buf.c-423-\t\tcase DUMP_PREFIX_ADDRESS:\nlib/seq_buf.c:424:\t\t\tret = seq_buf_printf(s, \"%s%p: %s\\n\",\nlib/seq_buf.c-425-\t\t\t prefix_str, ptr + i, linebuf);\n--\nlib/seq_buf.c-427-\t\tcase DUMP_PREFIX_OFFSET:\nlib/seq_buf.c:428:\t\t\tret = seq_buf_printf(s, \"%s%.8x: %s\\n\",\nlib/seq_buf.c-429-\t\t\t\t\t prefix_str, i, linebuf);\n--\nlib/seq_buf.c-431-\t\tdefault:\nlib/seq_buf.c:432:\t\t\tret = seq_buf_printf(s, \"%s%s\\n\", prefix_str, linebuf);\nlib/seq_buf.c-433-\t\t\tbreak;\n" }
85/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30128 output: 34 thoughts: 22 Thoughts: Here's my take on those lines of `lib/seq_buf.c`: Analyzing `lib/seq_buf.c` - Lines 67-104 Alright, let's dive into those lines in `lib/seq_buf.c` – 67 through 104, specifically. I want to see what's happening within that segment of code. It looks like we're likely dealing with the core buffering logic, given the file name. Based on the surrounding code, I'd expect to see operations related to either reading from or writing to the sequence buffer. This could be where we manage the circular buffer itself, track read/write pointers, or handle overflow conditions. My initial hypothesis is that this section contains a critical function, possibly a read or write method. I suspect we'll be dealing with pointer arithmetic, boundary checks, and potentially some form of locking to ensure thread safety. If this section involves writing, I anticipate seeing logic that handles filling the buffer, wrapping around to the beginning, and managing the `seq_buf`'s internal state. Conversely, if it's a read operation, I'm expecting to see logic that fetches data from the buffer, updates the read pointer, and deals with potential underflow conditions, i.e., trying to read past what's written. Given the context of a sequence buffer, which is likely used for streaming or sequential data access, memory management might also come into play here. We'll have to see how memory is allocated, deallocated, or managed dynamically. I'm keen to spot any performance optimizations, such as using prefetching, unrolling loops, or techniques to minimize memory accesses.
86/3	2026/09/15 11:14	tool	read-file	0m Args: { "File": "lib/seq_buf.c", "FirstLine": 67, "LineCount": 40 } Results: { "Contents": " 67:\tint seq_buf_vprintf(struct seq_buf s, const char fmt, va_list args)\n 68:\t{\n 69:\t\tint len;\n 70:\t\n 71:\t\tWARN_ON(s-\u003esize == 0);\n 72:\t\n 73:\t\tif (s-\u003elen \u003c s-\u003esize) {\n 74:\t\t\tlen = vsnprintf(s-\u003ebuffer + s-\u003elen, s-\u003esize - s-\u003elen, fmt, args);\n 75:\t\t\tif (s-\u003elen + len \u003c s-\u003esize) {\n 76:\t\t\t\ts-\u003elen += len;\n 77:\t\t\t\treturn 0;\n 78:\t\t\t}\n 79:\t\t}\n 80:\t\tseq_buf_set_overflow(s);\n 81:\t\treturn -1;\n 82:\t}\n 83:\t\n 84:\t/*\n 85:\t seq_buf_printf - sequence printing of information\n 86:\t * @s: seq_buf descriptor\n 87:\t * @fmt: printf format string\n 88:\t \n 89:\t Writes a printf() format into the sequence buffer.\n 90:\t \n 91:\t Returns: zero on success, -1 on overflow.\n 92:\t /\n 93:\tint seq_buf_printf(struct seq_buf s, const char fmt, ...)\n 94:\t{\n 95:\t\tva_list ap;\n 96:\t\tint ret;\n 97:\t\n 98:\t\tva_start(ap, fmt);\n 99:\t\tret = seq_buf_vprintf(s, fmt, ap);\n 100:\t\tva_end(ap);\n 101:\t\n 102:\t\treturn ret;\n 103:\t}\n 104:\tEXPORT_SYMBOL_GPL(seq_buf_printf);\n 105:\t\n 106:\t/*\n" }
87/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 31046 output: 34 thoughts: 464 Thoughts: Analyzing a Potential Buffer Overflow Okay, so I'm digging into this code and I've got a potential vulnerability to consider. `vsnprintf` is the key here; it writes into the buffer `s->buffer + s->len` and critically, always null-terminates the string it writes. That's good. But I need to verify that null-termination behavior with `seq_buf_str`. I'm checking this `seq_buf_str` function and it's interesting. It looks like it handles two cases. If there's space left in the buffer, it null-terminates at `s->buffer[s->len]`. But, if the buffer did overflow, it null-terminates at `s->buffer[s->size - 1]`. Now, I've got to look at this `control_read` function in `xe_gt_sriov_pf_debugfs.c`. I see it uses a `seq_buf` to build a string of commands, with `seq_buf_printf` being used in a loop. I'm focusing on the call to `simple_read_from_buffer`. And hold on... WAIT! I just spotted something that's making me double-take! I see `simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s));` and I need to know precisely what `seq_buf_used(&s)` is returning. I need to understand if `seq_buf_used` is taking into account the null-termination behavior of `seq_buf_str`. It's crucial here, because `simple_read_from_buffer` is going to read that much data. This is where a potential overflow could arise. I need to verify what `seq_buf_used` actually does.
88/3	2026/09/15 11:14	tool	grepper	0m Args: { "Expression": "seq_buf_used", "PathPrefix": "include/linux/seq_buf.h" } Results: { "Output": "include/linux/seq_buf.h=68=seq_buf_buffer_left(struct seq_buf s)\n--\ninclude/linux/seq_buf.h-76-/ How much buffer was written? /\ninclude/linux/seq_buf.h:77:static inline unsigned int seq_buf_used(struct seq_buf s)\ninclude/linux/seq_buf.h-78-{\n" }
89/3	2026/09/15 11:14	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 32059 output: 36 thoughts: 23 Thoughts: Here's my attempt at summarizing the thought process, as if I were a Linux kernel expert: Diving into `seq_buf.h` - Lines 65-82 Okay, time to get my hands dirty. I'm zeroing in on lines 65-82 of `include/linux/seq_buf.h`. This is where the core of the `seq_buf` implementation is, likely handling either allocation, resizing, or perhaps the actual data write process. Let's see... I bet there's some kind of structure definition in that range, probably something like `struct seq_buf` itself, or maybe a helper struct used internally. I'm expecting to see members for the buffer's current size, its allocated size, a pointer to the actual data, and maybe some flags for management. I'm also betting we'll see some inline functions or macros. I'm really curious to see how they handle potential overflows and memory management within the buffer. I am curious to see if they're taking a page-based approach, or a contiguous buffer approach, and how they implement that. Alright, let's take a look.
90/3	2026/09/15 11:15	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 65, "LineCount": 20 } Results: { "Contents": " 65:\t * How much buffer is left on the seq_buf?\n 66:\t /\n 67:\tstatic inline unsigned int\n 68:\tseq_buf_buffer_left(struct seq_buf s)\n 69:\t{\n 70:\t\tif (seq_buf_has_overflowed(s))\n 71:\t\t\treturn 0;\n 72:\t\n 73:\t\treturn s-\u003esize - s-\u003elen;\n 74:\t}\n 75:\t\n 76:\t/* How much buffer was written? /\n 77:\tstatic inline unsigned int seq_buf_used(struct seq_buf s)\n 78:\t{\n 79:\t\treturn min(s-\u003elen, s-\u003esize);\n 80:\t}\n 81:\t\n 82:\t/*\n 83:\t seq_buf_str - get NUL-terminated C string from seq_buf\n 84:\t * @s: the seq_buf handle\n" }
91/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 32627 output: 36 thoughts: 152 Thoughts: Analyzing `seq_buf_printf` Overflow Behavior Okay, hold on a second. I'm looking at how `seq_buf_printf` handles potential overflows, and there's a specific section I want to dig into. It's this block of code: ```c if (s->len < s->size) { len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args); if (s->len + len < s->size) { s->len += len; return 0; } } seq_buf_set_overflow(s); return -1; ``` Interesting. It looks like it tries to use `vsnprintf` within the allocated buffer. If there's enough space, it updates the length and returns zero, indicating success. But there's this `seq_buf_set_overflow(s)` call in the `else` block, followed by returning `-1`. What exactly is `seq_buf_set_overflow` doing? I need to understand that function call to have a complete picture of the overflow handling. Time to jump over to the header file, `include/linux/seq_buf.h`, and see what's defined there.
92/3	2026/09/15 11:15	tool	grepper	0m Args: { "Expression": "seq_buf_set_overflow", "PathPrefix": "include/linux/seq_buf.h" } Results: { "Output": "include/linux/seq_buf.h=58=static inline void\ninclude/linux/seq_buf.h:59:seq_buf_set_overflow(struct seq_buf s)\ninclude/linux/seq_buf.h-60-{\n--\ninclude/linux/seq_buf.h=141=static inline void seq_buf_commit(struct seq_buf s, int num)\n--\ninclude/linux/seq_buf.h-143-\tif (num \u003c 0) {\ninclude/linux/seq_buf.h:144:\t\tseq_buf_set_overflow(s);\ninclude/linux/seq_buf.h-145-\t} else {\n" }
93/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33279 output: 36 thoughts: 23 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into `seq_buf.h` Okay, time to get my hands dirty and look at the implementation details, specifically focusing on lines 50-65 of `include/linux/seq_buf.h`. I need to refresh my understanding of how this particular buffering mechanism is implemented. I'm especially curious about the memory allocation strategy and any potential optimizations they've built into it. Are they using a ring buffer? Or perhaps dynamic resizing based on some threshold? Let's see if there are any subtle tricks to avoid unnecessary copying or alignment issues. I'll be looking for clues in the data structure definitions, any inline functions related to buffer manipulation, and error handling. I hope to get a handle on the complexity of this section. I want to identify any design decisions, tradeoffs made. Are they optimizing for speed? or memory usage? I am hoping this will give me some insight.
94/3	2026/09/15 11:15	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 50, "LineCount": 20 } Results: { "Contents": " 50:\t * len is set to be greater than size.\n 51:\t /\n 52:\tstatic inline bool\n 53:\tseq_buf_has_overflowed(struct seq_buf s)\n 54:\t{\n 55:\t\treturn s-\u003elen \u003e s-\u003esize;\n 56:\t}\n 57:\t\n 58:\tstatic inline void\n 59:\tseq_buf_set_overflow(struct seq_buf s)\n 60:\t{\n 61:\t\ts-\u003elen = s-\u003esize + 1;\n 62:\t}\n 63:\t\n 64:\t/\n 65:\t * How much buffer is left on the seq_buf?\n 66:\t /\n 67:\tstatic inline unsigned int\n 68:\tseq_buf_buffer_left(struct seq_buf s)\n 69:\t{\n" }
95/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33785 output: 45 thoughts: 222 Thoughts: Analyzing the `control_read` Function Okay, hold on a second. I need to take a closer look at this `control_read` function. Specifically, I need to understand what it's really doing. The code snippet looks straightforward enough: it seems to be reading something into a buffer and then writing it out. But what exactly is being read? The function uses `seq_buf` and `simple_read_from_buffer`, which are common enough. It looks like it constructs a string with newline delimiters. The loop iterates through `control_cmds`. The crucial piece is `control_cmds`. What exactly is in `control_cmds`? And how many entries are there? That’s the key. I need to know the structure and the size of `control_cmds` to truly grasp the function's purpose. Let me go check `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c`, that's where I assume I'll find its definition. Knowing the structure and content of `control_cmds` will clarify everything.
96/3	2026/09/15 11:15	tool	grepper	0m Args: { "Expression": "control_cmds", "PathPrefix": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c" } Results: { "Output": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=618=static const struct {\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-620-\tint (fn)(struct xe_gt gt, unsigned int vfid);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:621:} control_cmds[] = {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-622-\t{ \"stop\", xe_gt_sriov_pf_control_stop_vf },\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=627=static ssize_t control_write(struct file file, const char __user buf, size_t count, loff_t pos)\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-651-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:652:\tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:653:\t\txe_gt_assert(gt, sizeof(cmd) \u003e strlen(control_cmds[n].cmd));\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-654-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:655:\t\tif (sysfs_streq(cmd, control_cmds[n].cmd)) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-656-\t\t\tguard(xe_pm_runtime)(xe);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:657:\t\t\tret = control_cmds[n].fn ? (control_cmds[n].fn)(gt, vfid) : 0;\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-658-\t\t\tbreak;\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=665=static ssize_t control_read(struct file file, char __user buf, size_t count, loff_t *ppos)\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-671-\tseq_buf_init(\u0026s, help, sizeof(help));\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:672:\tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:673:\t\tseq_buf_printf(\u0026s, \"%s\\n\", control_cmds[n].cmd);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-674-\t}\n" }
97/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35098 output: 50 thoughts: 12 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing the `control_cmds` Structure Okay, let's break this down. The first thing I'm doing is mentally dissecting the `control_cmds` object (or variable, depending on context). I'm not just glancing at it; I'm probing it, trying to determine its core structure. What are the key elements contained within it? Is it a list of dictionaries? A custom object with defined attributes? Does it use nested data structures? My initial approach is to mentally map out its composition. I'm looking for its fundamental building blocks and how they relate to each other. This is likely the crucial object that governs the commands or actions for the target process. I need to understand its form to understand its function. I'm focusing on the structural relationships first – the relationships and hierarchy between the commands. That should give me the foundation for the next stage.
98/3	2026/09/15 11:15	tool	read-file	0m Args: { "File": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c", "FirstLine": 618, "LineCount": 15 } Results: { "Contents": " 618:\tstatic const struct {\n 619:\t\tconst char cmd;\n 620:\t\tint (fn)(struct xe_gt gt, unsigned int vfid);\n 621:\t} control_cmds[] = {\n 622:\t\t{ \"stop\", xe_gt_sriov_pf_control_stop_vf },\n 623:\t\t{ \"pause\", xe_gt_sriov_pf_control_pause_vf },\n 624:\t\t{ \"resume\", xe_gt_sriov_pf_control_resume_vf },\n 625:\t};\n 626:\t\n 627:\tstatic ssize_t control_write(struct file file, const char __user buf, size_t count, loff_t pos)\n 628:\t{\n 629:\t\tstruct dentry dent = file_dentry(file);\n 630:\t\tstruct dentry parent = dent-\u003ed_parent;\n 631:\t\tstruct xe_gt gt = extract_gt(parent);\n 632:\t\tstruct xe_device xe = gt_to_xe(gt);\n" }
99/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35659 output: 32 thoughts: 293 Thoughts: Analyzing String Handling Okay, so I'm looking at this `control_cmds` thing and it's just three static strings, "stop", "pause", and "resume". That's tiny – probably around 20 bytes total. Definitely less than the 128 bytes I was initially considering. Hang on a second… I need to check something in the `synaptics_usb.c` driver, specifically, how they handle string construction with `usb_make_path`. This is interesting; I need to understand what's happening there to make sure my approach is optimized. I'm focusing on the buffer sizes and string operations now. Let's see what `usb_make_path` actually does.
100/3	2026/09/15 11:15	tool	grepper	0m Error: no matches Args: { "Expression": "int usb_make_path", "PathPrefix": "drivers/usb/core/" } Results: { "error": "no matches" }
101/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 36154 output: 30 thoughts: 13 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Investigating `usb_make_path` Alright, let's dive in. My immediate thought is to locate the definition of `usb_make_path`. This usually means I'm trying to understand how a USB device's path is constructed within the system. Is it a function, a macro, a data structure... and where is it declared? My understanding is a critical first step if I want to debug the USB subsystem. I'll need to know whether I'm looking for the code itself, to see what variables it acts on, or whether I'm looking for a data structure containing a path for a particular USB device. Perhaps I am looking to modify a particular structure to achieve a particular result. Knowing this will give context to how a USB path is created, and this in turn tells me what the system's "understanding" is. This is the starting point for any deeper analysis or modification I might need to make in this area. From here, I can examine its implementation, any related structures, and the calling contexts to build a complete picture.
102/3	2026/09/15 11:15	tool	grepper	0m Args: { "Expression": "usb_make_path\\(", "PathPrefix": "drivers/usb/" } Results: { "Output": "drivers/usb/atm/usbatm.c=1008=int usbatm_usb_probe(struct usb_interface intf, const struct usb_device_id id,\n--\ndrivers/usb/atm/usbatm.c-1048-\ndrivers/usb/atm/usbatm.c:1049:\tif (length \u003c= 0 \|\| (i = usb_make_path(usb_dev, buf, length)) \u003c 0)\ndrivers/usb/atm/usbatm.c-1050-\t\tgoto bind;\n--\ndrivers/usb/serial/usb-serial.c=543=static int serial_proc_show(struct seq_file m, void v)\n--\ndrivers/usb/serial/usb-serial.c-567-\t\tseq_printf(m, \" port:%d\", port-\u003eport_number);\ndrivers/usb/serial/usb-serial.c:568:\t\tusb_make_path(serial-\u003edev, tmp, sizeof(tmp));\ndrivers/usb/serial/usb-serial.c-569-\t\tseq_printf(m, \" path:%s\", tmp);\n--\ndrivers/usb/storage/onetouch.c=163=static int onetouch_connect_input(struct us_data *ss)\n--\ndrivers/usb/storage/onetouch.c-217-\ndrivers/usb/storage/onetouch.c:218:\tusb_make_path(udev, onetouch-\u003ephys, sizeof(onetouch-\u003ephys));\ndrivers/usb/storage/onetouch.c-219-\tstrlcat(onetouch-\u003ephys, \"/input0\", sizeof(onetouch-\u003ephys));\n" }
103/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 36852 output: 21 thoughts: 14 Thoughts: Here's a summary of my thought process, as if I were the one thinking it: Finding the `usb_make_path` Definition Okay, so I need to find the definition of `usb_make_path`. That's the starting point. It's likely a function, given the naming convention, and it's probably related to USB device paths, which is intriguing. I'm going to start by searching my project's codebase, and if that fails, I'll go digging through the kernel source documentation or the relevant USB subsystem header files. I'll be looking for where this function is declared, and importantly, how it's used. Understanding its context will be key. Is it part of the core USB stack, or a more specialized driver? Knowing its location will help me understand its significance in the bigger picture. From the definition, I will infer its inputs, outputs, and purpose.
104/3	2026/09/15 11:15	tool	grepper	0m Args: { "Expression": "int usb_make_path\\(" } Results: { "Output": "include/linux/usb.h=954=int usb_hub_release_port(struct usb_device hdev, unsigned port1,\n--\ninclude/linux/usb.h-981- /\ninclude/linux/usb.h:982:static inline int usb_make_path(struct usb_device dev, char buf, size_t size)\ninclude/linux/usb.h-983-{\n" }
105/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 37194 output: 35 thoughts: 20 Thoughts: Here's a summary of my thought process, as requested: Diving into USB Core - Specifically, That Header File Okay, so I need to get a handle on how USB device management is handled at a low level in the Linux kernel. I'm going to start by examining `include/linux/usb.h`, aiming for around line 982. Hopefully, that will give me some insight into the core data structures and function declarations related to device handling. I'm hoping to understand how devices are probed, registered, and managed from a high-level perspective, and where the core implementations of that reside. Line 982 could be pivotal. It's time to start digging!
106/3	2026/09/15 11:15	tool	read-file	0m Args: { "File": "include/linux/usb.h", "FirstLine": 980, "LineCount": 20 } Results: { "Contents": " 980:\t * high speed, and a different one if they are full or low speed.\n 981:\t /\n 982:\tstatic inline int usb_make_path(struct usb_device dev, char buf, size_t size)\n 983:\t{\n 984:\t\tint actual;\n 985:\t\tactual = snprintf(buf, size, \"usb-%s-%s\", dev-\u003ebus-\u003ebus_name,\n 986:\t\t\t\t dev-\u003edevpath);\n 987:\t\treturn (actual \u003e= (int)size) ? -1 : actual;\n 988:\t}\n 989:\t\n 990:\t/-------------------------------------------------------------------------*/\n 991:\t\n 992:\t#define USB_DEVICE_ID_MATCH_DEVICE \\\n 993:\t\t\t(USB_DEVICE_ID_MATCH_VENDOR \| USB_DEVICE_ID_MATCH_PRODUCT)\n 994:\t#define USB_DEVICE_ID_MATCH_DEV_RANGE \\\n 995:\t\t\t(USB_DEVICE_ID_MATCH_DEV_LO \| USB_DEVICE_ID_MATCH_DEV_HI)\n 996:\t#define USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION \\\n 997:\t\t\t(USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_DEV_RANGE)\n 998:\t#define USB_DEVICE_ID_MATCH_DEV_INFO \\\n 999:\t\t\t(USB_DEVICE_ID_MATCH_DEV_CLASS \| \\\n" }
107/3	2026/09/15 11:15	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 37788 output: 37 thoughts: 874 Thoughts: Analyzing USB Audio Card Naming in the Linux Kernel Okay, so I'm looking at this `usb_audio_make_longname` function, specifically in `sound/usb/card.c`. My initial thought was about how we're building this long name string, and I instinctively reached for `snprintf` because I'm used to ensuring null termination. But it seems like they're not using it directly. Instead, they're using this `seq_buf` structure, and it looks like it is intended to replace `snprintf`, and does handle null termination, but I'll have to verify that. Now, I see the code using this `seq_buf` and it immediately sets up a buffer with `seq_buf_init`. It looks like it uses `seq_buf_puts` to append the vendor name, manufacturer, and short name. Then it appends " at " to the end, before calling a function `usb_make_path`. The interesting part is `seq_buf_get_buf(&sb, &buf);`. The code then checks to make sure the returned `size` is > 0, indicating that it successfully retrieved a valid `buf` pointer and buffer `size`. If so, it calls `usb_make_path` to get the USB path, with the returned path length passed to `seq_buf_commit`. I'm thinking, let's look closer at `seq_buf_get_buf`. I'll switch over to the header file `include/linux/seq_buf.h` to dive deeper. My assumption, based on how the code is structured, is that this must be the mechanism for getting the underlying buffer from the `seq_buf` structure. I'll check how it works and whether it handles null termination properly.
108/3	2026/09/15 11:16	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 110, "LineCount": 40 } Results: { "Contents": " 110:\t\n 111:\t/*\n 112:\t seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t \n 116:\t Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t /\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf s, char *bufp)\n 120:\t{\n 121:\t\tWARN_ON(s-\u003elen \u003e s-\u003esize + 1);\n 122:\t\n 123:\t\tif (s-\u003elen \u003c s-\u003esize) {\n 124:\t\t\tbufp = s-\u003ebuffer + s-\u003elen;\n 125:\t\t\treturn s-\u003esize - s-\u003elen;\n 126:\t\t}\n 127:\t\n 128:\t\tbufp = NULL;\n 129:\t\treturn 0;\n 130:\t}\n 131:\t\n 132:\t/\n 133:\t seq_buf_commit - commit data to the buffer\n 134:\t * @s: the seq_buf handle\n 135:\t * @num: the number of bytes to commit\n 136:\t \n 137:\t Commit @num bytes of data written to a buffer previously acquired\n 138:\t * by seq_buf_get_buf(). To signal an error condition, or that the data\n 139:\t * didn't fit in the available space, pass a negative @num value.\n 140:\t /\n 141:\tstatic inline void seq_buf_commit(struct seq_buf s, int num)\n 142:\t{\n 143:\t\tif (num \u003c 0) {\n 144:\t\t\tseq_buf_set_overflow(s);\n 145:\t\t} else {\n 146:\t\t\t/* num must be negative on overflow */\n 147:\t\t\tBUG_ON(s-\u003elen + num \u003e s-\u003esize);\n 148:\t\t\ts-\u003elen += num;\n 149:\t\t}\n" }
109/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39682 output: 27 thoughts: 227 Thoughts: Analyzing the USB Path in `seq_buf_commit` Okay, let's break this down. I'm looking at `seq_buf_commit`, and the first thing that jumps out is `path_len = usb_make_path(dev, buf, size);`. Right, `path_len` is the result of `usb_make_path`. Now, what exactly does that function do? A quick look at its return value reveals an interesting condition: `return (actual >= (int)size) ? -1 : actual;`. So, if `actual` (the number of characters written) is less than `size`, it returns the actual number of characters written, excluding the null terminator. It's essentially telling us how many characters it successfully wrote to the buffer. And that buffer, `buf`, is `s->buffer + s->len`, meaning it's writing into an existing buffer, starting at a specific offset. Of course it will write the null terminator too. Then we have `seq_buf_commit(&sb, path_len)`. This is the crucial part. It's adding `path_len` to `sb.len`. If `path_len` is negative, we've got an overflow, and `seq_buf_set_overflow(&sb)` is called. Finally, before we're done, `seq_buf_str(&sb)` is invoked, which ensures that `card->longname` is properly null-terminated. Good practice. My next question is, where is `card->longname` allocated? I need to understand where this memory is coming from. Time to dig into the `struct snd_card` definition in `include/sound/core.h` to see how that's handled.
110/3	2026/09/15 11:16	tool	grepper	0m Args: { "Expression": "longname\\[", "PathPrefix": "include/sound/" } Results: { "Output": "include/sound/core.h=101=struct snd_card {\n--\ninclude/sound/core.h-107-\tchar shortname[32];\t\t/* short name of this soundcard /\ninclude/sound/core.h:108:\tchar longname[80];\t\t/ name of this soundcard /\ninclude/sound/core.h-109-\tchar irq_descr[32];\t\t/ Interrupt description */\n" }
111/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 40436 output: 35 thoughts: 480 Thoughts: Analyzing String Concatenation and Potential Buffer Overflows Okay, let's break this down. I see that `snd_card` is being allocated using `kzalloc` in `snd_card_new`. And I'm noticing that the `card->longname` is being initialized to zero. Interesting, and then `seq_buf_init` is called on that. But at the end `seq_buf_str` is called on the `card->longname`. Okay, `card->longname` is `kzalloc`'ed which means its length should be known to be zero when `seq_buf_init` is called, and at the end of it's lifecycle, the `seq_buf_str` function is called. Now, my mind immediately jumps to potential string vulnerabilities, so I'm diving into `include/linux/fortify-string.h` to see how `strcat` is handled. Let's see... Alright, here's `strcat`: First, there's a check for `p_size == SIZE_MAX`. If so, it calls `__underlying_strcat(p, q)`. Okay, probably not ideal. Otherwise, it calculates `p_len` using `__fortify_strlen(p)`. This is key. Then it uses `__builtin_snprintf` to append `q` to `p`, determining the `wanted` size. Finally, it checks if `p_size <= wanted`, and if so, it throws a `fortify_panic`. Wait a minute, what if `p_len` is greater than or equal to `p_size`? That means that the existing string `p` is already as long or longer than the allocated buffer! In that scenario, `__builtin_snprintf` will write past the end, overwriting memory, and there's no check for that case. That's a potential buffer overflow vulnerability right there, and a big problem! So now the question is: what does `__fortify_strlen(p)` actually do? I'm going to have to check that function definition to understand its behavior in this context.
112/3	2026/09/15 11:16	tool	grepper	0m Args: { "Expression": "__fortify_strlen", "PathPrefix": "include/linux/fortify-string.h" } Results: { "Output": "include/linux/fortify-string.h=169=__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)\n--\ninclude/linux/fortify-string.h-208-\t__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),\t\\\ninclude/linux/fortify-string.h:209:\t\t__builtin_strlen(p), __fortify_strlen(p))\ninclude/linux/fortify-string.h-210-__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\ninclude/linux/fortify-string.h:211:__kernel_size_t __fortify_strlen(const char * const POS p)\ninclude/linux/fortify-string.h-212-{\n--\ninclude/linux/fortify-string.h=363=char strcat(char const POS p, const char *q)\n--\ninclude/linux/fortify-string.h-369-\ninclude/linux/fortify-string.h:370:\tconst size_t p_len = __fortify_strlen(p);\ninclude/linux/fortify-string.h-371-\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n" }
113/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41779 output: 38 thoughts: 26 Thoughts: Here's my summary, as though I'm reading and processing the provided lines of code: Diving into `fortify-string.h` Okay, time to dig into the heart of the matter. Let's pull up lines 210-230 in `include/linux/fortify-string.h`. I'm expecting this section to deal with either direct buffer overflow protection or perhaps the enabling mechanisms around some of the compiler-based safety features. Given the file name, it's almost certainly related to string manipulation, which is a common source of vulnerabilities. I'm keen to see if it's using compile-time checks, runtime checks, or a combination of both. I'll be looking for macros or inline functions that are probably replacing standard C string functions, hopefully with added bounds checks or other safety features, likely utilizing the `__builtin_*` or similar compiler intrinsics to optimize the behavior. I’m hoping to gain insights into how the kernel mitigates string-related security risks, particularly with Fortify Source. I will also be considering if these are tied to any specific compiler flags or kernel configuration options. Let's see what’s there.
114/3	2026/09/15 11:16	tool	read-file	0m Args: { "File": "include/linux/fortify-string.h", "FirstLine": 210, "LineCount": 25 } Results: { "Contents": " 210:\t__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\n 211:\t__kernel_size_t __fortify_strlen(const char * const POS p)\n 212:\t{\n 213:\t\tconst size_t p_size = __member_size(p);\n 214:\t\t__kernel_size_t ret;\n 215:\t\n 216:\t\t/* Give up if we don't know how large p is. /\n 217:\t\tif (p_size == SIZE_MAX)\n 218:\t\t\treturn __underlying_strlen(p);\n 219:\t\tret = strnlen(p, p_size);\n 220:\t\tif (p_size \u003c= ret)\n 221:\t\t\tfortify_panic(FORTIFY_FUNC_strlen, FORTIFY_READ, p_size, ret + 1, ret);\n 222:\t\treturn ret;\n 223:\t}\n 224:\t\n 225:\t/ Defined after fortified strnlen() to reuse it. /\n 226:\textern ssize_t __real_strscpy(char , const char , size_t) __RENAME(sized_strscpy);\n 227:\t__FORTIFY_INLINE ssize_t sized_strscpy(char const POS p, const char * const POS q, size_t size)\n 228:\t{\n 229:\t\t/* Use string size rather than possible enclosing struct size. /\n 230:\t\tconst size_t p_size = __member_size(p);\n 231:\t\tconst size_t q_size = __member_size(q);\n 232:\t\tsize_t len;\n 233:\t\n 234:\t\t/ If we cannot get size of p and q default to call strscpy. */\n" }
115/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42573 output: 34 thoughts: 515 Thoughts: Analyzing a Potential Vulnerability in `net/devlink/dev.c` Okay, so I'm thinking about this potential buffer overflow. The crucial point is how `__fortify_strlen` and related checks work in conjunction with `snprintf`. If `p_size` (the buffer size) is less than or equal to `ret` (the result of the prior `strlen`), then a panic occurs. This means `p_len` (the current length) must be less than `p_size`, and therefore `p_size - p_len` must be greater than zero. This guarantees that `snprintf(p + p_len, p_size - p_len, "%s", q)` is safe from simple overflow. However, it's possible that if the string `q` is sufficiently large, then the combined result of the `snprintf` would trigger a `p_size <= wanted` which in turn triggers `fortify_panic`. So, there's a potential risk of a crash there. Now, let me shift my attention to `net/devlink/dev.c` where I see this code snippet: ```c @@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink devlink, { struct devlink_info_req req = {}; const struct nlattr nlattr; + struct seq_buf s; struct sk_buff msg; int rem, err; @@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink devlink, if (err) goto free_msg; + seq_buf_init(&s, buf, len); + s.len = strnlen(buf, len); nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING, (void )msg->data, msg->len, rem) { const struct nlattr kv; @@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink devlink, nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE, nlattr, rem_kv) { - strlcat(buf, nla_data(kv), len); - strlcat(buf, " ", len); + seq_buf_printf(&s, "%s ", (const char )nla_data(kv)); } } free_msg: ``` My initial thought is to scrutinize the calling context of `__devlink_compat_running_version` and determine what `buf` actually is, and the `len` passed. The code used to call `strlcat` on the buffer, but has been replaced with `seq_buf`. This is a welcome change. But I need to figure out the maximum size `buf` can reach to determine if there are potential overflow problems, or other errors. I need to consider what's happening before this code block and what happens with the `buf` after. I should also check the definition and usage of `struct seq_buf` very closely.
116/3	2026/09/15 11:16	tool	grepper	0m Args: { "Expression": "__devlink_compat_running_version", "PathPrefix": "net/devlink/" } Results: { "Output": "net/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c=1224=void devlink_compat_running_version(struct devlink *devlink,\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n" }
117/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 44137 output: 22 thoughts: 16 Thoughts: Here's a breakdown of my thought process, as requested: Tracing Calls to `devlink_compat_running_version` Okay, so I need to understand where `devlink_compat_running_version` is being called within the system. That suggests I'm probably looking at compatibility checks or version management related to `devlink` devices. I'm likely interested in how different versions of `devlink` are handled or if there are version-specific features being used. This could be for a few reasons. Perhaps I am debugging some devlink compatibility issues or I am looking to trace some code that uses devlink version in some important functionality. Perhaps I am doing code reviews and I want to understand who uses this function. I need to quickly locate all the call sites. Likely, I will use my tools to do this. I'll probably start with a `grep` or similar command to search the codebase for direct calls. I need to keep in mind that the name could be used in some indirect manner. If there is some macro or inline function that utilizes it, it is also important. So I must cast a wide net with my search. Once I've got that initial list, I can then dive into each call site to understand its context. From there, I'll need to see what each call is doing with the returned value, is it for logging, conditional checks, etc. This will help me build a complete picture of the role `devlink_compat_running_version` plays in the overall system.
118/3	2026/09/15 11:16	tool	grepper	0m Args: { "Expression": "devlink_compat_running_version" } Results: { "Output": "include/net/devlink.h=2121=void devlink_put(struct devlink devlink);\ninclude/net/devlink.h-2122-\ninclude/net/devlink.h:2123:void devlink_compat_running_version(struct devlink devlink,\ninclude/net/devlink.h-2124-\t\t\t\t char buf, size_t len);\n--\ninclude/net/devlink.h=2146=static inline void\ninclude/net/devlink.h:2147:devlink_compat_running_version(struct devlink devlink, char buf, size_t len)\ninclude/net/devlink.h-2148-{\n--\nnet/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c-1223-\nnet/devlink/dev.c:1224:void devlink_compat_running_version(struct devlink devlink,\nnet/devlink/dev.c-1225-\t\t\t\t char buf, size_t len)\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n--\nnet/ethtool/ioctl.c=3646=int dev_ethtool(struct net net, struct ifreq ifr, void __user useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t state-\u003einfo.fw_version,\n" }
119/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45095 output: 38 thoughts: 23 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into the Ethtool IOCTL Implementation Okay, time to get my hands dirty. I'm pretty sure the issue I'm chasing down is nestled somewhere within `net/ethtool/ioctl.c`, and I've got a hunch it's related to a particular IOCTL operation. Given the nature of the problem, I'm going to start my investigation right around line 3680. That location often deals with... [This is where you, the expert, would fill in the likely area of functionality. For example: "...handling specific features, configurations, or error conditions during the IOCTL calls. I anticipate it deals with the configuration of the network device."]. Let's see what the code around there reveals. I'll be looking for potential race conditions, incorrect parameter handling, or perhaps a subtle bug in the data structure manipulation. The goal is to quickly pinpoint the specific code path responsible for the erroneous behavior and understand the root cause. This is where I'll form a hypothesis and begin confirming it.
120/3	2026/09/15 11:16	tool	read-file	0m Args: { "File": "net/ethtool/ioctl.c", "FirstLine": 3670, "LineCount": 25 } Results: { "Contents": "3670:\t\tif (rc)\n3671:\t\t\tgoto exit_free;\n3672:\t\n3673:\t\tswitch (ethcmd) {\n3674:\t\tcase ETHTOOL_FLASHDEV:\n3675:\t\t\tif (state-\u003edevlink)\n3676:\t\t\t\trc = devlink_compat_flash_update(state-\u003edevlink,\n3677:\t\t\t\t\t\t\t\t state-\u003eefl.data);\n3678:\t\t\tbreak;\n3679:\t\tcase ETHTOOL_GDRVINFO:\n3680:\t\t\tif (state-\u003edevlink)\n3681:\t\t\t\tdevlink_compat_running_version(state-\u003edevlink,\n3682:\t\t\t\t\t\t\t state-\u003einfo.fw_version,\n3683:\t\t\t\t\t\t\t sizeof(state-\u003einfo.fw_version));\n3684:\t\t\tif (copy_to_user(useraddr, \u0026state-\u003einfo, sizeof(state-\u003einfo))) {\n3685:\t\t\t\trc = -EFAULT;\n3686:\t\t\t\tgoto exit_free;\n3687:\t\t\t}\n3688:\t\t\tbreak;\n3689:\t\t}\n3690:\t\n3691:\texit_free:\n3692:\t\tif (state-\u003edevlink)\n3693:\t\t\tdevlink_put(state-\u003edevlink);\n3694:\t\tkfree(state);\n" }
121/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45750 output: 34 thoughts: 40 Thoughts: Here's my take on the thought process, as if it were my own: ETHTOOL_GDRVINFO Investigation Alright, let's dive into this `ETHTOOL_GDRVINFO` situation. My immediate focus is on `state->info` – I need to understand what data it's holding and how it's being used within the context of the driver information retrieval. The critical piece of this puzzle is the `state` itself. Where is this structure allocated within the `dev_ethtool` function? I need to trace back the allocation and initialization of `state` to fully grasp its scope and purpose. Time to dig into the `dev_ethtool` code and follow the trail of `state`!
122/3	2026/09/15 11:16	tool	grepper	0m Args: { "Expression": "devlink_compat_running_version", "PathPrefix": "net/ethtool/" } Results: { "Output": "net/ethtool/ioctl.c=3646=int dev_ethtool(struct net net, struct ifreq ifr, void __user *useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t state-\u003einfo.fw_version,\n" }
123/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 46120 output: 38 thoughts: 27 Thoughts: Here's a summary of my thought process, as if I were the one reading this code: Diving into ethtool's ioctl Implementation Okay, time to dig into the `net/ethtool/ioctl.c` code again. Specifically, I'm focusing on lines 3640 through 3685. This range usually covers some critical functionality, and given the nature of ethtool's ioctls, it's likely dealing with either a fairly complex data structure interaction, or perhaps an important error condition handling. Given the line range, it is likely involved in the processing of some data from user space and applying it to the networking device, or the returning of results back to the user. I need to figure out what functionality this segment is responsible for, the data structures it manipulates, and any error paths it might take. Knowing the context of the surrounding code would be helpful. Understanding what ioctl command or commands are being handled here is critical for gaining a comprehensive view of the implementation and how it affects the kernel. Let's see... I'm expecting to potentially find calls to lower-level networking driver functions within this block, or some kind of validation logic. I'll need to pay close attention to potential race conditions, or access control violations, to make sure the code is safe and robust, especially considering user space interaction. Alright, let's get to it and read those lines carefully.
124/3	2026/09/15 11:16	tool	read-file	0m Args: { "File": "net/ethtool/ioctl.c", "FirstLine": 3640, "LineCount": 45 } Results: { "Contents": "3640:\t\t\trtnl_unlock();\n3641:\t\tnetdev_put(dev, \u0026dev_tracker);\n3642:\t\n3643:\t\treturn rc;\n3644:\t}\n3645:\t\n3646:\tint dev_ethtool(struct net net, struct ifreq ifr, void __user useraddr)\n3647:\t{\n3648:\t\tstruct ethtool_devlink_compat state;\n3649:\t\tu32 ethcmd;\n3650:\t\tint rc;\n3651:\t\n3652:\t\tif (copy_from_user(\u0026ethcmd, useraddr, sizeof(ethcmd)))\n3653:\t\t\treturn -EFAULT;\n3654:\t\n3655:\t\tstate = kzalloc_obj(*state);\n3656:\t\tif (!state)\n3657:\t\t\treturn -ENOMEM;\n3658:\t\n3659:\t\tswitch (ethcmd) {\n3660:\t\tcase ETHTOOL_FLASHDEV:\n3661:\t\t\tif (copy_from_user(\u0026state-\u003eefl, useraddr, sizeof(state-\u003eefl))) {\n3662:\t\t\t\trc = -EFAULT;\n3663:\t\t\t\tgoto exit_free;\n3664:\t\t\t}\n3665:\t\t\tstate-\u003eefl.data[ETHTOOL_FLASH_MAX_FILENAME - 1] = 0;\n3666:\t\t\tbreak;\n3667:\t\t}\n3668:\t\n3669:\t\trc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);\n3670:\t\tif (rc)\n3671:\t\t\tgoto exit_free;\n3672:\t\n3673:\t\tswitch (ethcmd) {\n3674:\t\tcase ETHTOOL_FLASHDEV:\n3675:\t\t\tif (state-\u003edevlink)\n3676:\t\t\t\trc = devlink_compat_flash_update(state-\u003edevlink,\n3677:\t\t\t\t\t\t\t\t state-\u003eefl.data);\n3678:\t\t\tbreak;\n3679:\t\tcase ETHTOOL_GDRVINFO:\n3680:\t\t\tif (state-\u003edevlink)\n3681:\t\t\t\tdevlink_compat_running_version(state-\u003edevlink,\n3682:\t\t\t\t\t\t\t state-\u003einfo.fw_version,\n3683:\t\t\t\t\t\t\t sizeof(state-\u003einfo.fw_version));\n3684:\t\t\tif (copy_to_user(useraddr, \u0026state-\u003einfo, sizeof(state-\u003einfo))) {\n" }
125/3	2026/09/15 11:16	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 47155 output: 30 thoughts: 874 Thoughts: Analyzing Potential Buffer Overflows in Kernel Code Okay, so I'm looking at this `__devlink_compat_running_version` function, and it uses `seq_buf_printf` to build a string. The initial state `state` was allocated with `kzalloc_obj`, so its `info` member should be zeroed out to begin with. The code then uses `nla_for_each_attr_type` and `nla_for_each_nested_type` to iterate through Netlink attributes and uses `seq_buf_printf` to construct a string in a buffer, `buf`. The question here is, what happens to the buffer if `seq_buf_printf` goes wrong, say, if there's an overflow or missing null termination? Aha, `seq_buf_printf` uses `vsnprintf`. And `vsnprintf`, I know, is guaranteed to null-terminate the buffer, even on overflow! Alright, but what if there's a real overflow? Let's dig deeper and look at the `seq_buf_vprintf` in `lib/seq_buf.c`. Okay, here it is: `if (s->len < s->size)` is the crucial check before writing to the buffer. `vsnprintf` writes up to `s->size - s->len` bytes. Importantly, even if that results in an overflow, `vsnprintf` is going to ensure there's a null terminator, placed at `s->size - 1`. If there's an overflow, the `seq_buf_set_overflow` function is called and it sets the `s->len` to something larger than the buffer size. Subsequent calls will then find that `s->len >= s->size`, so they won't write anything. Consequently, the buffer will remain null-terminated, which is safe. Plus, `state->info` was zeroed anyway, so the string should be safe even if something went wrong there. Alright, moving on, let's look at `net/sunrpc/addr.c` and specifically `rpc_sockaddr2uaddr`. This function converts a socket address to a "uaddr" string, using `snprintf`. The code handles both IPv4 and IPv6 addresses. There are two other important functions, `rpc_ntop4` and `rpc_ntop6_noscopeid`. I'll have to figure out what those functions return!
126/3	2026/09/15 11:17	tool	grepper	0m Args: { "Expression": "rpc_ntop4", "PathPrefix": "net/sunrpc/" } Results: { "Output": "net/sunrpc/addr.c=104=static size_t rpc_ntop6(const struct sockaddr sap,\n--\nnet/sunrpc/addr.c-111-\nnet/sunrpc/addr.c:112:static int rpc_ntop4(const struct sockaddr sap,\nnet/sunrpc/addr.c-113-\t\t char buf, const size_t buflen)\n--\nnet/sunrpc/addr.c=129=size_t rpc_ntop(const struct sockaddr sap, char buf, const size_t buflen)\n--\nnet/sunrpc/addr.c-132-\tcase AF_INET:\nnet/sunrpc/addr.c:133:\t\treturn rpc_ntop4(sap, buf, buflen);\nnet/sunrpc/addr.c-134-\tcase AF_INET6:\n--\nnet/sunrpc/addr.c=265=char rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)\n--\nnet/sunrpc/addr.c-272-\tcase AF_INET:\nnet/sunrpc/addr.c:273:\t\tlen = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));\nnet/sunrpc/addr.c-274-\t\tif (len == 0 \|\| len \u003e= sizeof(addrbuf))\n" }
127/3	2026/09/15 11:17	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 48951 output: 36 thoughts: 24 Thoughts: Here's my summary, as if I were thinking these thoughts: Analyzing `net/sunrpc/addr.c` - Lines 110-128 Alright, I need to zero in on a specific section of this file. Let's pull up lines 110 through 128 of `net/sunrpc/addr.c`. This usually means there's some interesting network address-related logic happening there, likely some crucial socket or RPC setup or parsing is going on. I expect it could be dealing with address family handling or possibly some initial socket options or parsing address data during connection establishment. It might relate to address translation between different formats (e.g., IPv4 to IPv6), or maybe even dealing with multicast addresses, which often require special handling. Let's see what the code actually does in that region. I'll be looking for any indications of potential bugs, inefficiencies, or areas that could benefit from performance optimization, especially around the interaction with the socket layer and the RPC data structures. This is core networking code, so I need to be thorough.
128/3	2026/09/15 11:17	tool	read-file	0m Args: { "File": "net/sunrpc/addr.c", "FirstLine": 110, "LineCount": 20 } Results: { "Contents": " 110:\t#endif\t/* !IS_ENABLED(CONFIG_IPV6) /\n 111:\t\n 112:\tstatic int rpc_ntop4(const struct sockaddr sap,\n 113:\t\t\t char buf, const size_t buflen)\n 114:\t{\n 115:\t\tconst struct sockaddr_in sin = (struct sockaddr_in )sap;\n 116:\t\n 117:\t\treturn snprintf(buf, buflen, \"%pI4\", \u0026sin-\u003esin_addr);\n 118:\t}\n 119:\t\n 120:\t/\n 121:\t rpc_ntop - construct a presentation address in @buf\n 122:\t * @sap: socket address\n 123:\t * @buf: construction area\n 124:\t * @buflen: size of @buf, in bytes\n 125:\t \n 126:\t Plants a %NUL-terminated string in @buf and returns the length\n 127:\t * of the string, excluding the %NUL. Otherwise zero is returned.\n 128:\t /\n 129:\tsize_t rpc_ntop(const struct sockaddr sap, char *buf, const size_t buflen)\n" }
129/3	2026/09/15 11:17	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 49582 output: 39 thoughts: 1489 Thoughts: Code Review: String Formatting and Buffer Handling Okay, so I've gone through the code snippets, focusing on potential buffer overflow vulnerabilities. It appears the initial concern was regarding string manipulation, specifically around concatenation and formatting within various drivers. First, I examined `rpc_ntop4`. Here, `rpc_ntop4` correctly sets up `addrbuf`, formats the IP address portion, and then uses `kstrdup` to duplicate the string. There are no immediate issues; the use of `snprintf` combined with the initial null termination ensures safety. The function returns `NULL` on overflow, indicating a well-managed error condition. Moving onto `sound/pci/ac97/ac97_codec.c`, the previous code used `strlcat`. This code has been updated to use `snprintf` with `strlen` to determine the offset. This pattern is common in several instances. It reads the current length of the destination buffer and then uses the result as an offset for the subsequent `snprintf` call, ensuring that the function formats the string into the appropriate location, and also performs bound checks to make sure we don't overflow the buffer. This is a very robust and correct usage of `snprintf`. Similarly, `sound/usb/mixer.c` shows the safe usage of `snprintf` within `append_ctl_name`. They are checking the current length with `strlen`, determining whether the string can be written or not. It correctly calculates the remaining space and uses `snprintf` with an offset to append the new string, which addresses any potential overflows. `drivers/media/dvb-frontends/si2165.c` uses `snprintf` directly, which eliminates any concern about manually managing concatenation. It provides the full length of the destination and uses `snprintf` safely. `drivers/net/ethernet/intel/i40e/i40e.h` also shows a safe use of `snprintf`. It calculates the offset in the buffer based on the current length, which is safe. It checks the length and ensures the destination buffer is not overflown. Finally, `drivers/net/wireless/ath/wil6210/wmi.c` uses a combination of techniques with a `seq_buf`. This abstraction looks interesting, but at the end, `seq_buf_str(&s)` ensures proper null termination of the resulting string. I'd need to examine the `seq_buf` implementation to be absolutely sure, but on the surface, this appears to be a safe alternative to manual string manipulation. I also confirmed that `string` is safely passed to the called function. In conclusion, it seems that there's a good understanding of the risks associated with buffer overflows in this codebase. The use of `snprintf` with proper length checks and offset calculations, or the use of abstractions that provide similar guarantees, demonstrates a focus on safe string manipulation. I am confident in the safety of these code snippets.
130/3	2026/09/15 11:18	tool	grepper	0m Args: { "Expression": "resume_triggers2string", "PathPrefix": "drivers/net/wireless/ath/wil6210/" } Results: { "Output": "drivers/net/wireless/ath/wil6210/wmi.c=3100=int wmi_suspend(struct wil6210_priv wil)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3163-\ndrivers/net/wireless/ath/wil6210/wmi.c:3164:static void resume_triggers2string(u32 triggers, char string, int str_size)\ndrivers/net/wireless/ath/wil6210/wmi.c-3165-{\n--\ndrivers/net/wireless/ath/wil6210/wmi.c=3192=int wmi_resume(struct wil6210_priv *wil)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3210-\t\treturn rc;\ndrivers/net/wireless/ath/wil6210/wmi.c:3211:\tresume_triggers2string(le32_to_cpu(reply.evt.resume_triggers), string,\ndrivers/net/wireless/ath/wil6210/wmi.c-3212-\t\t\t sizeof(string));\n" }
131/3	2026/09/15 11:18	llm	kmsan-evaluator	3m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 52058 output: 33 thoughts: 901 Thoughts: Analyzing String Handling and Potential Vulnerabilities Okay, so I'm looking at this code and immediately my attention is drawn to the string handling. Specifically, I see `char string[100];` within `wmi_resume`. It's null-terminated with `seq_buf_str(&s)`, and then used with `wil_dbg_wmi`. Seems straightforward enough, but I always want to make sure I understand the context. My immediate thought is to check how firmware paths are constructed. I've jumped into `drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c` to see how it's handled, particularly this section: ```c snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s", mp_path, (end == '/') ? "" : "/", mapping_table[i].fw_base, fwnames[j].extension); ``` Ah, `snprintf`. Good, it's being used to format the firmware path. This means that the path is null-terminated, which is a key part of preventing buffer overflows. The use of `BRCMF_FW_NAME_LEN` as the buffer size provides another layer of security, making this specific part pretty robust in my opinion. Always good to see proper string formatting and size limitations. Now, that brings me to the `/chosen` node in the Device Tree, so I check `drivers/of/fdt.c`. I see this code, which handles the system command line: ```c if (!fdt) goto handle_cmdline; { size_t len = strlen(cmdline); if (len < COMMAND_LINE_SIZE) snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE); } ``` Okay, so if the FDT isn't present, it goes to `handle_cmdline`. It uses `snprintf`, which is good. I like that it's checking the length before appending the config command line. Looks like they're trying to be careful here, which is what I expect. Essentially, if `fdt` is null, it skips the FDT handling and goes straight to the command line concatenation, which should be safe given the use of `snprintf` and the length check.
132/3	2026/09/15 11:21	tool	grepper	0m Args: { "Expression": "handle_cmdline:", "PathPrefix": "drivers/of/fdt.c" } Results: { "Output": "drivers/of/fdt.c=1091=int __init early_init_dt_scan_chosen(char cmdline)\n--\ndrivers/of/fdt.c-1130-\ndrivers/of/fdt.c:1131:handle_cmdline:\ndrivers/of/fdt.c-1132-\t/\n" }
133/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 53635 output: 37 thoughts: 26 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into `fdt.c` for Context Okay, so I need to understand what's happening with device tree parsing in the `drivers/of/fdt.c` file, specifically from lines 1090 to 1150. Given what I already know about FDT, that section likely handles a specific aspect of node processing or property handling. I'm guessing it might be related to… well, it could be anything, really. I could be looking at initialization, resource assignment, or perhaps some specific error handling related to how the DTB is interpreted. Let me get into those lines and see what's actually going on. This might relate to my current debugging or a deeper dive into DT handling. I suspect this section is relevant to a specific platform I'm working on right now, or maybe related to a recent bug report. Alright, let's get to the code.
134/3	2026/09/15 11:21	tool	read-file	0m Args: { "File": "drivers/of/fdt.c", "FirstLine": 1090, "LineCount": 60 } Results: { "Contents": "1090:\t\n1091:\tint __init early_init_dt_scan_chosen(char cmdline)\n1092:\t{\n1093:\t\tint l, node;\n1094:\t\tconst char p;\n1095:\t\tconst void rng_seed;\n1096:\t\tconst void fdt = initial_boot_params;\n1097:\t\n1098:\t\tif (!fdt)\n1099:\t\t\tgoto handle_cmdline;\n1100:\t\n1101:\t\tnode = fdt_path_offset(fdt, \"/chosen\");\n1102:\t\tif (node \u003c 0)\n1103:\t\t\tnode = fdt_path_offset(fdt, \"/chosen@0\");\n1104:\t\tif (node \u003c 0)\n1105:\t\t\t/* Handle the cmdline config options even if no /chosen node /\n1106:\t\t\tgoto handle_cmdline;\n1107:\t\n1108:\t\tchosen_node_offset = node;\n1109:\t\n1110:\t\tearly_init_dt_check_for_initrd(node);\n1111:\t\tearly_init_dt_check_for_elfcorehdr(node);\n1112:\t\tearly_init_dt_check_for_dmcryptkeys(node);\n1113:\t\n1114:\t\trng_seed = of_get_flat_dt_prop(node, \"rng-seed\", \u0026l);\n1115:\t\tif (rng_seed \u0026\u0026 l \u003e 0) {\n1116:\t\t\tadd_bootloader_randomness(rng_seed, l);\n1117:\t\n1118:\t\t\t/ try to clear seed so it won't be found. /\n1119:\t\t\tfdt_nop_property(initial_boot_params, node, \"rng-seed\");\n1120:\t\n1121:\t\t\t/ update CRC check value /\n1122:\t\t\tof_fdt_crc32 = crc32_be(~0, initial_boot_params,\n1123:\t\t\t\t\tfdt_totalsize(initial_boot_params));\n1124:\t\t}\n1125:\t\n1126:\t\t/ Retrieve command line /\n1127:\t\tp = of_get_flat_dt_prop(node, \"bootargs\", \u0026l);\n1128:\t\tif (p != NULL \u0026\u0026 l \u003e 0)\n1129:\t\t\tstrscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));\n1130:\t\n1131:\thandle_cmdline:\n1132:\t\t/\n1133:\t\t * CONFIG_CMDLINE is meant to be a default in case nothing else\n1134:\t\t * managed to set the command line, unless CONFIG_CMDLINE_FORCE\n1135:\t\t * is set in which case we override whatever was found earlier.\n1136:\t\t /\n1137:\t#ifdef CONFIG_CMDLINE\n1138:\t#if defined(CONFIG_CMDLINE_EXTEND)\n1139:\t\t{\n1140:\t\t\tsize_t len = strlen(cmdline);\n1141:\t\n1142:\t\t\tif (len \u003c COMMAND_LINE_SIZE)\n1143:\t\t\t\tsnprintf(cmdline + len, COMMAND_LINE_SIZE - len, \" %s\", CONFIG_CMDLINE);\n1144:\t\t}\n1145:\t#elif defined(CONFIG_CMDLINE_FORCE)\n1146:\t\tstrscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n1147:\t#else\n1148:\t\t/ No arguments from boot loader, use kernel's cmdl/\n1149:\t\tif (!((char )cmdline)[0])\n" }
135/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 54875 output: 43 thoughts: 1046 Thoughts: Analyzing String Formatting in Kernel Code Okay, so I'm looking at this `early_init_dt_scan_chosen` function, which from the looks of it, is an initialization routine that runs very early in the boot process. I'm wondering about string manipulation in the kernel. First, I examined `drivers/pinctrl/samsung/pinctrl-samsung.c`. The code uses `snprintf` to construct a pin bank name. Standard, nothing unusual there. Then, I shifted my focus to `drivers/scsi/bfa/bfa_fcs.c`. Here, the code uses `snprintf` to create symbolic names (`sym_name` and `node_sym_name`) for Fibre Channel ports. It concatenates various pieces of information like the model, version, machine name, and OS details, separated by `BFA_FCS_PORT_SYMBNAME_SEPARATOR`. I have to wonder, though, are these symbolic names sent over the Fibre Channel, or potentially exposed to userspace? That's a security consideration. To answer that question, I need to understand how these names are used. So, I need to check `bfa_fcs_fabric_psymb_init` and `bfa_fcs_fabric_nsymb_init`. Wait, in `bfa_fcs_fabric_psymb_init`... let's see what changed! I see that `port_cfg->sym_name.symname` used to be constructed using `strscpy` and `strlcat`, which means it would not have been fully zeroed before use, and was instead constructed with the length of the string, and then null-terminated. Now it's being constructed using `snprintf`. I need to figure out how it's being used. The crucial question: is `port_cfg->sym_name.symname` being initialized to a specific length or a zeroed value? This could have security implications if sensitive data isn't properly handled.
136/3	2026/09/15 11:21	tool	read-file	0m Args: { "File": "drivers/scsi/bfa/bfa_fcs.c", "FirstLine": 755, "LineCount": 45 } Results: { "Contents": " 755:\tbfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s fabric)\n 756:\t{\n 757:\t\tstruct bfa_lport_cfg_s port_cfg = \u0026fabric-\u003ebport.port_cfg;\n 758:\t\tchar model[BFA_ADAPTER_MODEL_NAME_LEN] = {0};\n 759:\t\tstruct bfa_fcs_driver_info_s driver_info = \u0026fabric-\u003efcs-\u003edriver_info;\n 760:\t\n 761:\t\tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n 762:\t\n 763:\t\t/\n 764:\t\t * Host OS Info :\n 765:\t\t * If OS Patch Info is not there, do not truncate any bytes from the\n 766:\t\t * OS name string and instead copy the entire OS info string (64 bytes).\n 767:\t\t /\n 768:\t\tif (driver_info-\u003ehost_os_patch[0] == '\\0') {\n 769:\t\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n 770:\t\t\t\t \"%s%s%s%s%s%s%s%s\",\n 771:\t\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 772:\t\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 773:\t\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 774:\t\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);\n 775:\t\t} else {\n 776:\t\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n 777:\t\t\t\t \"%s%s%s%s%s%s%s%s%s\",\n 778:\t\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 779:\t\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 780:\t\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 781:\t\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 782:\t\t\t\t driver_info-\u003ehost_os_patch);\n 783:\t\t}\n 784:\t\n 785:\t\t/ null terminate /\n 786:\t\tport_cfg-\u003esym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;\n 787:\t}\n 788:\t\n 789:\t/\n 790:\t * Node Symbolic Name Creation for base port and all vports\n 791:\t /\n 792:\tvoid\n 793:\tbfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s fabric)\n 794:\t{\n 795:\t\tstruct bfa_lport_cfg_s port_cfg = \u0026fabric-\u003ebport.port_cfg;\n 796:\t\tchar model[BFA_ADAPTER_MODEL_NAME_LEN] = {0};\n 797:\t\tstruct bfa_fcs_driver_info_s driver_info = \u0026fabric-\u003efcs-\u003edriver_info;\n 798:\t\n 799:\t\tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n" }
137/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 57343 output: 40 thoughts: 1513 Thoughts: Analyzing String Concatenation and Safety Okay, so I'm looking at this code and immediately I see a pattern regarding string manipulation, specifically concatenation, and I need to assess its safety. First, I noticed this initial snippet where `strscpy` is used, followed by `strlcat`. I recall, `strlcat` has inherent safety features with the `strlcat` vs `snprintf` comparison. However, the use of `snprintf` is cleaner, because `strlcat` is a bit of a relic. It doesn't zero-terminate strings. `snprintf` does terminate the string. `snprintf` is cleaner. I started digging, and I checked `fs/nfs/nfsroot.c`, which showed `snprintf` replacing multiple calls to `strlcat`. Good, safe practice there. The code neatly handles the comma insertion and the source string concatenation within a single call. This is the correct way, avoiding multiple operations, and it's cleaner. Then I moved to `fs/orangefs/orangefs-debugfs.c`. In this function `orangefs_prepare_debugfs_help_string`, I noticed a potential problem. This `new` string allocation seems a bit involved. Specifically, I'm concerned about how `strlcat` is used multiple times to build the debug help string. The comments mention checking for overflow, but I need to make sure this is actually robust. Looking at the code from lines 630-645, I confirmed that `new` is allocated with `kzalloc`. The critical question is whether using a buffer, such as `seq_buf` will keep the code safe from overflow. Okay, the code using `seq_buf`, and then `strlcpy` is a clean way to do it. So, in summary, this suggests a gradual shift from `strlcat` to `snprintf` for safer concatenation, and `seq_buf` is a great way to build the resulting string.
138/3	2026/09/15 11:21	tool	read-file	0m Args: { "File": "fs/orangefs/orangefs-debugfs.c", "FirstLine": 630, "LineCount": 25 } Results: { "Contents": " 630:\t\tstruct seq_buf s;\n 631:\t\n 632:\t\tgossip_debug(GOSSIP_UTILS_DEBUG, \"%s: start\\n\", __func__);\n 633:\t\n 634:\t\tif (at_boot)\n 635:\t\t\tclient_title = HELP_STRING_UNINITIALIZED;\n 636:\t\n 637:\t\t/* build a new debug_help_string. /\n 638:\t\tnew = kzalloc(DEBUG_HELP_STRING_SIZE, GFP_KERNEL);\n 639:\t\tif (!new) {\n 640:\t\t\trc = -ENOMEM;\n 641:\t\t\tgoto out;\n 642:\t\t}\n 643:\t\n 644:\t\tseq_buf_init(\u0026s, new, string_size);\n 645:\t\n 646:\t\t/\n 647:\t\t * We'll just plow through here building our new debug\n 648:\t\t * help string and let seq_buf take care of assuring that\n 649:\t\t * dst doesn't overflow.\n 650:\t\t */\n 651:\t\tseq_buf_puts(\u0026s, client_title);\n 652:\t\n 653:\t\tif (!at_boot) {\n 654:\t\n" }
139/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 59670 output: 34 thoughts: 322 Thoughts: Analyzing Potential Uninitialized Memory Access After kzalloc Okay, so `new` was kzalloc'ed, which usually means things are zeroed, but I need to be absolutely sure. Let's dig into these modified files and look for any sneaky uninitialized memory accesses. It's easy to miss something subtle, especially with string manipulations. First, `arch/arm/kernel/atags_parse.c`: in `parse_tag_cmdline`, `default_command_line` seems safe. The code calculates the length using `strlen` of a statically allocated or zeroed buffer and then appends to it using `snprintf`. No obvious issues there. Now, `arch/loongarch/kernel/setup.c`. `bootcmdline_init` uses a `seq_buf`. This is where I need to be careful. The code initializes `s.buffer`, `s.size`, and `s.len` before using it, which is good. But... wait a minute... does `struct seq_buf` have other fields? Are those initialized? I'd better check the definition in `include/linux/seq_buf.h` to see. Gotta be thorough.
140/3	2026/09/15 11:21	tool	grepper	0m Error: bad expression: fatal: -e option, 'struct seq_buf {': Unmatched \{ Args: { "Expression": "struct seq_buf {", "PathPrefix": "include/linux/seq_buf.h" } Results: { "error": "bad expression: fatal: -e option, 'struct seq_buf {': Unmatched \\{" }
141/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 60314 output: 35 thoughts: 22 Thoughts: Okay, let's dive into this. Here's my take on those initial lines: Initial Assessment of `include/linux/seq_buf.h` Alright, I'm going to start by getting a handle on the beginning of `include/linux/seq_buf.h`. I'll scan the first forty lines. Usually, that's enough to get a grasp of the basic structure, included headers, and maybe some initial definitions or function prototypes. I expect to see some `#include` directives—likely for standard headers, memory management routines, and potentially some core kernel data structures like linked lists or memory pools if this is related to managing buffers. I'll be looking for the main data structure definition: `struct seq_buf`. Understanding its members is key – pointers to buffers, lengths, read/write pointers, flags... it'll give me a strong indication of how the buffer is managed. I'll pay attention to any inline functions or macros, too; those usually indicate performance-critical operations. The goal is to get a baseline understanding of the buffer's fundamental properties and operations. I will be looking for common features such as adding, reading and removing from buffers, probably some kind of locking mechanism and error handling too.
142/3	2026/09/15 11:21	tool	read-file	0m Args: { "File": "include/linux/seq_buf.h", "FirstLine": 1, "LineCount": 40 } Results: { "Contents": " 1:\t/* SPDX-License-Identifier: GPL-2.0 /\n 2:\t#ifndef _LINUX_SEQ_BUF_H\n 3:\t#define _LINUX_SEQ_BUF_H\n 4:\t\n 5:\t#include \u003clinux/bug.h\u003e\n 6:\t#include \u003clinux/minmax.h\u003e\n 7:\t#include \u003clinux/seq_file.h\u003e\n 8:\t#include \u003clinux/types.h\u003e\n 9:\t\n 10:\t/\n 11:\t * Trace sequences are used to allow a function to call several other functions\n 12:\t * to create a string of data to use.\n 13:\t /\n 14:\t\n 15:\t/\n 16:\t struct seq_buf - seq buffer structure\n 17:\t * @buffer:\tpointer to the buffer\n 18:\t * @size:\tsize of the buffer\n 19:\t * @len:\tthe amount of data inside the buffer\n 20:\t /\n 21:\tstruct seq_buf {\n 22:\t\tchar\t\t\tbuffer;\n 23:\t\tsize_t\t\t\tsize;\n 24:\t\tsize_t\t\t\tlen;\n 25:\t};\n 26:\t\n 27:\t#define DECLARE_SEQ_BUF(NAME, SIZE)\t\t\t\\\n 28:\t\tstruct seq_buf NAME = {\t\t\t\t\\\n 29:\t\t\t.buffer = (char[SIZE]) { 0 },\t\t\\\n 30:\t\t\t.size = SIZE,\t\t\t\t\\\n 31:\t\t}\n 32:\t\n 33:\tstatic inline void seq_buf_clear(struct seq_buf *s)\n 34:\t{\n 35:\t\ts-\u003elen = 0;\n 36:\t\tif (s-\u003esize)\n 37:\t\t\ts-\u003ebuffer[0] = '\\0';\n 38:\t}\n 39:\t\n 40:\tstatic inline void\n" }
143/3	2026/09/15 11:21	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 61130 output: 317 thoughts: 2450 Thoughts: Analysis of Memory Safety in the Kernel Codebase Okay, so I've gone through this list of code snippets, and I'm pretty confident in the overall memory safety profile. I'm seeing a consistent pattern of using safe string manipulation functions, particularly `snprintf` and `strscpy`, alongside the `seq_buf` utility, to prevent uninitialized memory reads and potential buffer overflows. Initially, I looked at how `struct seq_buf` is used, and in all cases across architectures (`loongarch`, `parisc`) and diverse drivers (comedi, drm, xe, input, media, net, etc.) the buffers are initialized correctly. That's a good starting point. The buffer, size and length fields are consistently initialized before any operation. Furthermore, the `seq_buf` methods, such as `seq_buf_printf` and `seq_buf_str`, are being utilized correctly, ensuring null termination and bounded writes. This is in contrast to `strcat` that can be dangerous. The cases of `snprintf` are also reassuring. In various contexts, including command lines, device names, and debug output (e.g., `si2165.c`, `i40e.h`, `fdt.c`, `pinctrl-samsung.c`, `bfa_fcs.c`, `nfsroot.c`, `ac97_codec.c`, `card.c`, `mixer.c`), it’s being used to format strings into buffers of known size, which avoids overflows. The use of `strscpy` after `snprintf` in the `x86/kernel/setup.c` code ensures the string is copied safely and null-terminated. Looking for the 4 criteria for `NeedsKMSAN` I can see no evidence of them. There are no kernel structures passed to user space that aren't fully initialized, no conditional logic depending on uninitialized data, and no complex data structures where uninitialized fields are read. The code carefully uses bounded and safe writes, and no uninitialized memory leaks appear to be present. Crucially, in the code sections I've analyzed, particularly in those involving `seq_buf` and string manipulation, the buffers are either explicitly initialized, kzalloc'd, or the lengths are carefully managed. Any potential overflow issues would be caught by KASAN and FORTIFY_SOURCE. Therefore, my assessment is that `NeedsKMSAN` is false for all these cases. I'm ready to call `set-results`.
144/3	2026/09/15 11:22	tool	set-results	0m Args: { "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false }

Trajectory: (Expand/Collapse All)

Seq

Timestamp

Type

Name

Duration

0/0

2026/09/15 11:08

flow

patch-triage

14m

Args:

null

Results:

{
  "EnableConfigs": [
    "SND_USB_AUDIO",
    "MOUSE_SYNAPTICS_USB",
    "SUNRPC",
    "COMEDI_BOND",
    "COMEDI_MISC_DRIVERS",
    "COMEDI",
    "FORTIFY_SOURCE"
  ],
  "FocusSymbols": [
    "usb_audio_make_longname",
    "snd_usb_audio_create",
    "build_connector_control",
    "synusb_probe",
    "rpc_sockaddr2uaddr",
    "devlink_compat_running_version",
    "bonding_attach"
  ],
  "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.",
  "WorthFuzzing": true
}

1/1

2026/09/15 11:08

action

read-patch-diff

Args:

null

Results:

{
  "PatchDiff": "commit 7af038477662f04c34c484a45e1a571280e5f258\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Tue Sep 15 11:08:01 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c\nindex 4ec591bde3dfa..21140b44d96e6 100644\n--- a/arch/arm/kernel/atags_parse.c\n+++ b/arch/arm/kernel/atags_parse.c\n@@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision);\n static int __init parse_tag_cmdline(const struct tag *tag)\n {\n #if defined(CONFIG_CMDLINE_EXTEND)\n-\tstrlcat(default_command_line, \" \", COMMAND_LINE_SIZE);\n-\tstrlcat(default_command_line, tag-\u003eu.cmdline.cmdline,\n-\t\tCOMMAND_LINE_SIZE);\n+\tsize_t len = strlen(default_command_line);\n+\n+\tsnprintf(default_command_line + len, COMMAND_LINE_SIZE - len,\n+\t\t \" %s\", tag-\u003eu.cmdline.cmdline);\n #elif defined(CONFIG_CMDLINE_FORCE)\n \tpr_warn(\"Ignoring tag cmdline (using the default kernel command line)\\n\");\n #else\ndiff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c\nindex 6fa4a22a58fd6..826396f141b9c 100644\n--- a/arch/loongarch/kernel/setup.c\n+++ b/arch/loongarch/kernel/setup.c\n@@ -33,6 +33,7 @@\n #include \u003clinux/of_address.h\u003e\n #include \u003clinux/suspend.h\u003e\n #include \u003clinux/swiotlb.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003casm/addrspace.h\u003e\n #include \u003casm/alternative.h\u003e\n@@ -305,6 +306,8 @@ static void __init fdt_setup(void)\n \n static void __init bootcmdline_init(char **cmdline_p)\n {\n+\tstruct seq_buf s;\n+\n \t/*\n \t * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line\n \t * is trivial - we simply use the built-in command line unconditionally \u0026\n@@ -315,6 +318,11 @@ static void __init bootcmdline_init(char **cmdline_p)\n \t\tgoto out;\n \t}\n \n+\t/* Initialize seq_buf pointing to boot_command_line */\n+\ts.buffer = boot_command_line;\n+\ts.size = COMMAND_LINE_SIZE;\n+\ts.len = strlen(boot_command_line);\n+\n #ifdef CONFIG_OF_FLATTREE\n \t/*\n \t * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system,\n@@ -323,11 +331,11 @@ static void __init bootcmdline_init(char **cmdline_p)\n \t * to boot_command_line.\n \t */\n \tif (initial_boot_params) {\n-\t\tif (boot_command_line[0])\n-\t\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n+\t\tif (s.len)\n+\t\t\tseq_buf_puts(\u0026s, \" \");\n \n-\t\tif (!strstr(boot_command_line, init_command_line))\n-\t\t\tstrlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE);\n+\t\tif (!strstr(s.buffer, init_command_line))\n+\t\t\tseq_buf_puts(\u0026s, init_command_line);\n \n \t\tgoto out;\n \t}\n@@ -338,14 +346,14 @@ static void __init bootcmdline_init(char **cmdline_p)\n \t * CONFIG_CMDLINE_EXTEND is enabled.\n \t */\n \tif (IS_ENABLED(CONFIG_CMDLINE_EXTEND) \u0026\u0026 CONFIG_CMDLINE[0]) {\n-\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n-\t\tstrlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n+\t\tseq_buf_puts(\u0026s, \" \");\n+\t\tseq_buf_puts(\u0026s, CONFIG_CMDLINE);\n \t}\n \n \t/*\n \t * Use built-in command line if the bootloader command line is empty.\n \t */\n-\tif (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) \u0026\u0026 !boot_command_line[0])\n+\tif (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) \u0026\u0026 !s.len)\n \t\tstrscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n \n out:\ndiff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c\nindex 1ae6d0c0e1d67..0d9c2137d6758 100644\n--- a/arch/mips/kernel/setup.c\n+++ b/arch/mips/kernel/setup.c\n@@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void)\n \n static void __init bootcmdline_append(const char *s, size_t max)\n {\n+\tsize_t len;\n+\tint prec;\n+\n \tif (!s[0] || !max)\n \t\treturn;\n \n-\tif (boot_command_line[0])\n-\t\tstrlcat(boot_command_line, \" \", COMMAND_LINE_SIZE);\n+\tlen = strlen(boot_command_line);\n+\tif (len \u003e= COMMAND_LINE_SIZE - 1)\n+\t\treturn;\n \n-\tstrlcat(boot_command_line, s, max);\n+\tif (len) {\n+\t\tif (COMMAND_LINE_SIZE - len \u003c 3)\n+\t\t\treturn;\n+\n+\t\tprec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2);\n+\t\tsnprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, \" %.*s\",\n+\t\t\t prec, s);\n+\t} else {\n+\t\tprec = min_t(size_t, max, COMMAND_LINE_SIZE - 1);\n+\t\tsnprintf(boot_command_line, COMMAND_LINE_SIZE, \"%.*s\",\n+\t\t\t prec, s);\n+\t}\n }\n \n #ifdef CONFIG_OF_EARLY_FLATTREE\ndiff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c\nindex d3e17a7a89016..fa3efc82ad874 100644\n--- a/arch/parisc/kernel/setup.c\n+++ b/arch/parisc/kernel/setup.c\n@@ -17,6 +17,7 @@\n #include \u003clinux/init.h\u003e\n #include \u003clinux/console.h\u003e\n #include \u003clinux/seq_file.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #define PCI_DEBUG\n #include \u003clinux/pci.h\u003e\n #undef PCI_DEBUG\n@@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE];\n static void __init setup_cmdline(char **cmdline_p)\n {\n \textern unsigned int boot_args[];\n+\tstruct seq_buf s;\n \tchar *p;\n \n \t*cmdline_p = command_line;\n@@ -54,19 +56,21 @@ static void __init setup_cmdline(char **cmdline_p)\n \tstrscpy(boot_command_line, (char *)__va(boot_args[1]),\n \t\tCOMMAND_LINE_SIZE);\n \n+\ts.buffer = boot_command_line;\n+\ts.size = COMMAND_LINE_SIZE;\n+\ts.len = strlen(boot_command_line);\n+\n \t/* autodetect console type (if not done by palo yet) */\n \tp = boot_command_line;\n \tif (!str_has_prefix(p, \"console=\") \u0026\u0026 !strstr(p, \" console=\")) {\n-\t\tstrlcat(p, \" console=\", COMMAND_LINE_SIZE);\n-\t\tif (PAGE0-\u003emem_cons.cl_class == CL_DUPLEX)\n-\t\t\tstrlcat(p, \"ttyS0\", COMMAND_LINE_SIZE);\n-\t\telse\n-\t\t\tstrlcat(p, \"tty0\", COMMAND_LINE_SIZE);\n+\t\tseq_buf_printf(\u0026s, \" console=%s\",\n+\t\t\t       PAGE0-\u003emem_cons.cl_class == CL_DUPLEX ?\n+\t\t\t       \"ttyS0\" : \"tty0\");\n \t}\n \n \t/* default to use early console */\n \tif (!strstr(p, \"earlycon\"))\n-\t\tstrlcat(p, \" earlycon=pdc\", COMMAND_LINE_SIZE);\n+\t\tseq_buf_printf(\u0026s, \" earlycon=pdc\");\n \n #ifdef CONFIG_BLK_DEV_INITRD\n \t/* did palo pass us a ramdisk? */\ndiff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c\nindex cda6adb9f69c4..c40e0edd7c136 100644\n--- a/arch/x86/kernel/setup.c\n+++ b/arch/x86/kernel/setup.c\n@@ -916,9 +916,11 @@ void __init setup_arch(char **cmdline_p)\n #else\n \tif (builtin_cmdline[0]) {\n \t\t/* append boot loader cmdline to builtin */\n-\t\tstrlcat(builtin_cmdline, \" \", COMMAND_LINE_SIZE);\n-\t\tstrlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);\n-\t\tstrscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);\n+\t\tchar tmp[COMMAND_LINE_SIZE];\n+\n+\t\tsnprintf(tmp, COMMAND_LINE_SIZE, \"%s %s\", builtin_cmdline, boot_command_line);\n+\t\tstrscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE);\n+\t\tstrscpy(boot_command_line, tmp, COMMAND_LINE_SIZE);\n \t}\n #endif\n \tbuiltin_cmdline_added = true;\ndiff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c\nindex 8e10ecab4f0dc..a10cfbd04c728 100644\n--- a/drivers/comedi/drivers/comedi_bond.c\n+++ b/drivers/comedi/drivers/comedi_bond.c\n@@ -39,6 +39,7 @@\n \n #include \u003clinux/module.h\u003e\n #include \u003clinux/string.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/slab.h\u003e\n #include \u003clinux/comedi.h\u003e\n #include \u003clinux/comedi/comedilib.h\u003e\n@@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\n {\n \tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\n \tDECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);\n+\tstruct seq_buf s;\n \tint i;\n \n \tmemset(\u0026devs_opened, 0, sizeof(devs_opened));\n-\tdevpriv-\u003ename[0] = 0;\n+\tseq_buf_init(\u0026s, devpriv-\u003ename, sizeof(devpriv-\u003ename));\n \t/*\n \t * Loop through all comedi devices specified on the command-line,\n \t * building our device list.\n@@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\n \t\t\t}\n \t\t\tdevpriv-\u003edevs = devs;\n \t\t\tdevpriv-\u003edevs[devpriv-\u003endevs++] = bdev;\n-\t\t\t{\n-\t\t\t\t/* Append dev:subdev to devpriv-\u003ename */\n-\t\t\t\tchar buf[20];\n-\n-\t\t\t\tsnprintf(buf, sizeof(buf), \"%u:%u \",\n-\t\t\t\t\t bdev-\u003eminor, bdev-\u003esubdev);\n-\t\t\t\tstrlcat(devpriv-\u003ename, buf,\n-\t\t\t\t\tsizeof(devpriv-\u003ename));\n-\t\t\t}\n+\n+\t\t\t/* Append dev:subdev to devpriv-\u003ename */\n+\t\t\tseq_buf_printf(\u0026s, \"%u:%u \", bdev-\u003eminor, bdev-\u003esubdev);\n \t\t}\n \t}\n \n@@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\n \t\treturn -EINVAL;\n \t}\n \n+\tseq_buf_str(\u0026s);\n+\n \treturn 0;\n }\n \ndiff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c\nindex 9c0a1e48f96f2..4e3781815b6d7 100644\n--- a/drivers/edac/thunderx_edac.c\n+++ b/drivers/edac/thunderx_edac.c\n@@ -20,6 +20,7 @@\n #include \u003clinux/atomic.h\u003e\n #include \u003clinux/bitfield.h\u003e\n #include \u003clinux/circ_buf.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003casm/page.h\u003e\n \n@@ -47,12 +48,17 @@ static void decode_register(char *str, size_t size,\n {\n \tint ret = 0;\n \n+\tif (size \u003e 0)\n+\t\tstr[0] = '\\0';\n+\n \twhile (descr-\u003etype \u0026\u0026 descr-\u003emask \u0026\u0026 descr-\u003edescr) {\n \t\tif (reg \u0026 descr-\u003emask) {\n \t\t\tret = snprintf(str, size, \"\\n\\t%s, %s\",\n \t\t\t\t       descr-\u003etype == ERR_CORRECTED ?\n \t\t\t\t\t \"Corrected\" : \"Uncorrected\",\n \t\t\t\t       descr-\u003edescr);\n+\t\t\tif (ret \u003c 0 || ret \u003e= size)\n+\t\t\t\tbreak;\n \t\t\tstr += ret;\n \t\t\tsize -= ret;\n \t\t}\n@@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)\n \n \twhile (CIRC_CNT(ocx-\u003ecom_ring_head, ocx-\u003ecom_ring_tail,\n \t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx))) {\n+\t\tstruct seq_buf s;\n+\n \t\ttail = ring_pos(ocx-\u003ecom_ring_tail,\n \t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx));\n \t\tctx = \u0026ocx-\u003ecom_err_ctx[tail];\n \n-\t\tsnprintf(msg, OCX_MESSAGE_SIZE, \"%s: OCX_COM_INT: %016llx\",\n-\t\t\tocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n+\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_INT: %016llx\",\n+\t\t\t       ocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n \n \t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\tocx_com_errors, ctx-\u003ereg_com_int);\n \n-\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tfor (lane = 0; lane \u003c OCX_RX_LANES; lane++)\n \t\t\tif (ctx-\u003ereg_com_int \u0026 BIT(lane)) {\n-\t\t\t\tsnprintf(other, OCX_OTHER_SIZE,\n-\t\t\t\t\t \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n-\t\t\t\t\t lane, ctx-\u003ereg_lane_int[lane],\n-\t\t\t\t\t lane, ctx-\u003ereg_lane_stat11[lane]);\n-\n-\t\t\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\t\t\tseq_buf_printf(\u0026s,\n+\t\t\t\t\t       \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n+\t\t\t\t\t       lane, ctx-\u003ereg_lane_int[lane],\n+\t\t\t\t\t       lane, ctx-\u003ereg_lane_stat11[lane]);\n \n \t\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\t\t\tocx_lane_errors,\n \t\t\t\t\t\tctx-\u003ereg_lane_int[lane]);\n-\t\t\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\t\t\tseq_buf_puts(\u0026s, other);\n \t\t\t}\n \n \t\tif (ctx-\u003ereg_com_int \u0026 OCX_COM_INT_CE)\n-\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tocx-\u003ecom_ring_tail++;\n \t}\n@@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id)\n \n \twhile (CIRC_CNT(ocx-\u003elink_ring_head, ocx-\u003elink_ring_tail,\n \t\t\tARRAY_SIZE(ocx-\u003elink_err_ctx))) {\n+\t\tstruct seq_buf s;\n+\n \t\ttail = ring_pos(ocx-\u003elink_ring_head,\n \t\t\t\tARRAY_SIZE(ocx-\u003elink_err_ctx));\n \n \t\tctx = \u0026ocx-\u003elink_err_ctx[tail];\n \n-\t\tsnprintf(msg, OCX_MESSAGE_SIZE,\n-\t\t\t \"%s: OCX_COM_LINK_INT[%d]: %016llx\",\n-\t\t\t ocx-\u003eedac_dev-\u003ectl_name,\n-\t\t\t ctx-\u003elink, ctx-\u003ereg_com_link_int);\n+\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_LINK_INT[%d]: %016llx\",\n+\t\t\t       ocx-\u003eedac_dev-\u003ectl_name,\n+\t\t\t       ctx-\u003elink, ctx-\u003ereg_com_link_int);\n \n \t\tdecode_register(other, OCX_OTHER_SIZE,\n \t\t\t\tocx_com_link_errors, ctx-\u003ereg_com_link_int);\n \n-\t\tstrlcat(msg, other, OCX_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tif (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_UE)\n-\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \t\telse if (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_CE)\n-\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tocx-\u003elink_ring_tail++;\n \t}\n@@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)\n \n \twhile (CIRC_CNT(l2c-\u003ering_head, l2c-\u003ering_tail,\n \t\t\tARRAY_SIZE(l2c-\u003eerr_ctx))) {\n-\t\tsnprintf(msg, L2C_MESSAGE_SIZE,\n-\t\t\t \"%s: %s: %016llx, %s: %016llx\",\n-\t\t\t l2c-\u003eedac_dev-\u003ectl_name, reg_int_name, ctx-\u003ereg_int,\n-\t\t\t ctx-\u003ereg_ext_name, ctx-\u003ereg_ext);\n+\t\tstruct seq_buf s;\n+\n+\t\ttail = ring_pos(l2c-\u003ering_tail, ARRAY_SIZE(l2c-\u003eerr_ctx));\n+\t\tctx = \u0026l2c-\u003eerr_ctx[tail];\n+\n+\t\tseq_buf_init(\u0026s, msg, L2C_MESSAGE_SIZE);\n+\n+\t\tseq_buf_printf(\u0026s, \"%s: %s: %016llx, %s: %016llx\",\n+\t\t\t       l2c-\u003eedac_dev-\u003ectl_name, reg_int_name, ctx-\u003ereg_int,\n+\t\t\t       ctx-\u003ereg_ext_name, ctx-\u003ereg_ext);\n \n \t\tdecode_register(other, L2C_OTHER_SIZE, l2_errors, ctx-\u003ereg_int);\n \n-\t\tstrlcat(msg, other, L2C_MESSAGE_SIZE);\n+\t\tseq_buf_puts(\u0026s, other);\n \n \t\tif (ctx-\u003ereg_int \u0026 mask_ue)\n-\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \t\telse if (ctx-\u003ereg_int \u0026 mask_ce)\n-\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, msg);\n+\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\n \n \t\tl2c-\u003ering_tail++;\n \t}\ndiff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c\nindex 7ce9e212770ad..229b5fec44bff 100644\n--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c\n+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c\n@@ -29,6 +29,7 @@\n #include \u003clinux/kernel.h\u003e\n #include \u003clinux/random.h\u003e\n #include \u003clinux/sched.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/seq_file.h\u003e\n \n #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)\n@@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,\n \t\t\t\tchar *proppath,\n \t\t\t\tsize_t proppath_size)\n {\n+\tstruct seq_buf s;\n \tint i;\n-\tchar temp[8];\n \n-\tsnprintf(proppath, proppath_size, \"mst:%d\", mstb-\u003emgr-\u003econn_base_id);\n+\tseq_buf_init(\u0026s, proppath, proppath_size);\n+\n+\tseq_buf_printf(\u0026s, \"mst:%d\", mstb-\u003emgr-\u003econn_base_id);\n \tfor (i = 0; i \u003c (mstb-\u003elct - 1); i++) {\n \t\tint shift = (i % 2) ? 0 : 4;\n \t\tint port_num = (mstb-\u003erad[i / 2] \u003e\u003e shift) \u0026 0xf;\n \n-\t\tsnprintf(temp, sizeof(temp), \"-%d\", port_num);\n-\t\tstrlcat(proppath, temp, proppath_size);\n+\t\tseq_buf_printf(\u0026s, \"-%d\", port_num);\n \t}\n-\tsnprintf(temp, sizeof(temp), \"-%d\", pnum);\n-\tstrlcat(proppath, temp, proppath_size);\n+\tseq_buf_printf(\u0026s, \"-%d\", pnum);\n+\n+\tseq_buf_str(\u0026s);\n }\n \n /**\ndiff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\nindex 0f242db775e1c..548a50f744224 100644\n--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\n+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c\n@@ -4,6 +4,7 @@\n  */\n \n #include \u003clinux/debugfs.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003cdrm/drm_print.h\u003e\n #include \u003cdrm/drm_debugfs.h\u003e\n@@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,\n \tstruct xe_hw_engine *hwe;\n \tenum xe_hw_engine_id id;\n \tchar engines[128];\n+\tstruct seq_buf s;\n+\tconst char *s_str;\n \n-\tengines[0] = '\\0';\n+\tseq_buf_init(\u0026s, engines, sizeof(engines));\n \n \tif (group \u003c num_groups) {\n \t\tfor_each_hw_engine(hwe, gt, id) {\n@@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,\n \t\t\tu16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe);\n \t\t\tu32 mask = groups[group].engines[guc_class];\n \n-\t\t\tif (mask \u0026 BIT(guc_logical_instance)) {\n-\t\t\t\tstrlcat(engines, hwe-\u003ename, sizeof(engines));\n-\t\t\t\tstrlcat(engines, \" \", sizeof(engines));\n-\t\t\t}\n+\t\t\tif (mask \u0026 BIT(guc_logical_instance))\n+\t\t\t\tseq_buf_printf(\u0026s, \"%s \", hwe-\u003ename);\n \t\t}\n-\t\tstrlcat(engines, \"\\n\", sizeof(engines));\n+\t\tseq_buf_puts(\u0026s, \"\\n\");\n \t}\n \n-\treturn simple_read_from_buffer(buf, count, ppos, engines, strlen(engines));\n+\ts_str = seq_buf_str(\u0026s);\n+\treturn simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));\n }\n \n static const struct file_operations sched_group_engines_fops = {\n@@ -663,15 +665,15 @@ static ssize_t control_write(struct file *file, const char __user *buf, size_t c\n static ssize_t control_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)\n {\n \tchar help[128];\n+\tstruct seq_buf s;\n \tsize_t n;\n \n-\thelp[0] = '\\0';\n+\tseq_buf_init(\u0026s, help, sizeof(help));\n \tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\n-\t\tstrlcat(help, control_cmds[n].cmd, sizeof(help));\n-\t\tstrlcat(help, \"\\n\", sizeof(help));\n+\t\tseq_buf_printf(\u0026s, \"%s\\n\", control_cmds[n].cmd);\n \t}\n \n-\treturn simple_read_from_buffer(buf, count, ppos, help, strlen(help));\n+\treturn simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(\u0026s));\n }\n \n static const struct file_operations control_ops = {\ndiff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c\nindex 880a0c79148cd..d13d2d6202ee5 100644\n--- a/drivers/input/mouse/synaptics_usb.c\n+++ b/drivers/input/mouse/synaptics_usb.c\n@@ -41,6 +41,7 @@\n #include \u003clinux/usb.h\u003e\n #include \u003clinux/input.h\u003e\n #include \u003clinux/usb/input.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #define USB_VENDOR_ID_SYNAPTICS\t0x06cb\n #define USB_DEVICE_ID_SYNAPTICS_TP\t0x0001\t/* Synaptics USB TouchPad */\n@@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface *intf,\n \tstruct input_dev *input_dev;\n \tunsigned int intf_num = intf-\u003ecur_altsetting-\u003edesc.bInterfaceNumber;\n \tunsigned int altsetting = min(intf-\u003enum_altsetting, 1U);\n+\tstruct seq_buf s;\n+\tchar path[64];\n \tint error;\n \n \terror = usb_set_interface(udev, intf_num, altsetting);\n@@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface *intf,\n \t\t\t ep-\u003ebInterval);\n \tsynusb-\u003eurb-\u003etransfer_flags |= URB_NO_TRANSFER_DMA_MAP;\n \n+\tseq_buf_init(\u0026s, synusb-\u003ename, sizeof(synusb-\u003ename));\n+\n \tif (udev-\u003emanufacturer)\n-\t\tstrscpy(synusb-\u003ename, udev-\u003emanufacturer,\n-\t\t\tsizeof(synusb-\u003ename));\n+\t\tseq_buf_puts(\u0026s, udev-\u003emanufacturer);\n \n \tif (udev-\u003eproduct) {\n \t\tif (udev-\u003emanufacturer)\n-\t\t\tstrlcat(synusb-\u003ename, \" \", sizeof(synusb-\u003ename));\n-\t\tstrlcat(synusb-\u003ename, udev-\u003eproduct, sizeof(synusb-\u003ename));\n+\t\t\tseq_buf_puts(\u0026s, \" \");\n+\t\tseq_buf_puts(\u0026s, udev-\u003eproduct);\n \t}\n \n-\tif (!strlen(synusb-\u003ename))\n-\t\tsnprintf(synusb-\u003ename, sizeof(synusb-\u003ename),\n-\t\t\t \"USB Synaptics Device %04x:%04x\",\n-\t\t\t le16_to_cpu(udev-\u003edescriptor.idVendor),\n-\t\t\t le16_to_cpu(udev-\u003edescriptor.idProduct));\n+\tif (!seq_buf_used(\u0026s))\n+\t\tseq_buf_printf(\u0026s, \"USB Synaptics Device %04x:%04x\",\n+\t\t\t       le16_to_cpu(udev-\u003edescriptor.idVendor),\n+\t\t\t       le16_to_cpu(udev-\u003edescriptor.idProduct));\n \n \tif (synusb-\u003eflags \u0026 SYNUSB_STICK)\n-\t\tstrlcat(synusb-\u003ename, \" (Stick)\", sizeof(synusb-\u003ename));\n+\t\tseq_buf_puts(\u0026s, \" (Stick)\");\n+\n+\tseq_buf_str(\u0026s);\n \n-\tusb_make_path(udev, synusb-\u003ephys, sizeof(synusb-\u003ephys));\n-\tstrlcat(synusb-\u003ephys, \"/input0\", sizeof(synusb-\u003ephys));\n+\tusb_make_path(udev, path, sizeof(path));\n+\tsnprintf(synusb-\u003ephys, sizeof(synusb-\u003ephys), \"%s/input0\", path);\n \n \tinput_dev-\u003ename = synusb-\u003ename;\n \tinput_dev-\u003ephys = synusb-\u003ephys;\ndiff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c\nindex f1241b63aa5ce..bd15eb58fc84f 100644\n--- a/drivers/media/dvb-frontends/si2165.c\n+++ b/drivers/media/dvb-frontends/si2165.c\n@@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client *client)\n \t\tchip_name, rev_char, state-\u003echip_type,\n \t\tstate-\u003echip_revcode);\n \n-\tstrlcat(state-\u003efe.ops.info.name, chip_name,\n-\t\tsizeof(state-\u003efe.ops.info.name));\n+\tsnprintf(state-\u003efe.ops.info.name, sizeof(state-\u003efe.ops.info.name),\n+\t\t \"Silicon Labs %s%s%s\",\n+\t\t chip_name,\n+\t\t state-\u003ehas_dvbt ? \" DVB-T\" : \"\",\n+\t\t state-\u003ehas_dvbc ? \" DVB-C\" : \"\");\n \n \tn = 0;\n-\tif (state-\u003ehas_dvbt) {\n+\tif (state-\u003ehas_dvbt)\n \t\tstate-\u003efe.ops.delsys[n++] = SYS_DVBT;\n-\t\tstrlcat(state-\u003efe.ops.info.name, \" DVB-T\",\n-\t\t\tsizeof(state-\u003efe.ops.info.name));\n-\t}\n-\tif (state-\u003ehas_dvbc) {\n+\tif (state-\u003ehas_dvbc)\n \t\tstate-\u003efe.ops.delsys[n++] = SYS_DVBC_ANNEX_A;\n-\t\tstrlcat(state-\u003efe.ops.info.name, \" DVB-C\",\n-\t\t\tsizeof(state-\u003efe.ops.info.name));\n-\t}\n \n \t/* return fe pointer */\n \t*pdata-\u003efe = \u0026state-\u003efe;\ndiff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h\nindex 1b6a8fbaa6485..9f792128a0efe 100644\n--- a/drivers/net/ethernet/intel/i40e/i40e.h\n+++ b/drivers/net/ethernet/intel/i40e/i40e.h\n@@ -1059,19 +1059,26 @@ static inline char *i40e_nvm_version_str(struct i40e_hw *hw, char *buf,\n \t\t\t\t\t size_t len)\n {\n \tchar ver[16] = \" \";\n+\tsize_t offset;\n \n \t/* Get NVM version */\n \ti40e_info_nvm_ver(hw, buf, len);\n \n \t/* Append EETrackID if provided */\n \ti40e_info_eetrack(hw, \u0026ver[1], sizeof(ver) - 1);\n-\tif (strlen(ver) \u003e 1)\n-\t\tstrlcat(buf, ver, len);\n+\tif (strlen(ver) \u003e 1) {\n+\t\toffset = strlen(buf);\n+\t\tif (offset \u003c len)\n+\t\t\tsnprintf(buf + offset, len - offset, \"%s\", ver);\n+\t}\n \n \t/* Append combo image version if provided */\n \ti40e_info_civd_ver(hw, \u0026ver[1], sizeof(ver) - 1);\n-\tif (strlen(ver) \u003e 1)\n-\t\tstrlcat(buf, ver, len);\n+\tif (strlen(ver) \u003e 1) {\n+\t\toffset = strlen(buf);\n+\t\tif (offset \u003c len)\n+\t\t\tsnprintf(buf + offset, len - offset, \"%s\", ver);\n+\t}\n \n \treturn buf;\n }\ndiff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c\nindex 479b2418ca340..fcc9e9eb57322 100644\n--- a/drivers/net/wireless/ath/wil6210/wmi.c\n+++ b/drivers/net/wireless/ath/wil6210/wmi.c\n@@ -7,6 +7,7 @@\n #include \u003clinux/moduleparam.h\u003e\n #include \u003clinux/etherdevice.h\u003e\n #include \u003clinux/if_arp.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \"wil6210.h\"\n #include \"txrx.h\"\n@@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv *wil)\n \n static void resume_triggers2string(u32 triggers, char *string, int str_size)\n {\n-\tstring[0] = '\\0';\n+\tstruct seq_buf s;\n+\n+\tseq_buf_init(\u0026s, string, str_size);\n \n \tif (!triggers) {\n-\t\tstrlcat(string, \" UNKNOWN\", str_size);\n-\t\treturn;\n-\t}\n+\t\tseq_buf_puts(\u0026s, \" UNKNOWN\");\n+\t} else {\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_HOST)\n+\t\t\tseq_buf_puts(\u0026s, \" HOST\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_HOST)\n-\t\tstrlcat(string, \" HOST\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_UCAST_RX)\n+\t\t\tseq_buf_puts(\u0026s, \" UCAST_RX\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_UCAST_RX)\n-\t\tstrlcat(string, \" UCAST_RX\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_BCAST_RX)\n+\t\t\tseq_buf_puts(\u0026s, \" BCAST_RX\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_BCAST_RX)\n-\t\tstrlcat(string, \" BCAST_RX\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_WMI_EVT)\n+\t\t\tseq_buf_puts(\u0026s, \" WMI_EVT\");\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_WMI_EVT)\n-\t\tstrlcat(string, \" WMI_EVT\", str_size);\n+\t\tif (triggers \u0026 WMI_RESUME_TRIGGER_DISCONNECT)\n+\t\t\tseq_buf_puts(\u0026s, \" DISCONNECT\");\n+\t}\n \n-\tif (triggers \u0026 WMI_RESUME_TRIGGER_DISCONNECT)\n-\t\tstrlcat(string, \" DISCONNECT\", str_size);\n+\tseq_buf_str(\u0026s);\n }\n \n int wmi_resume(struct wil6210_priv *wil)\ndiff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\nindex 22ff326f1924a..2f74a952599ec 100644\n--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\n+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c\n@@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev,\n \tfwreq-\u003en_items = n_fwnames;\n \n \tfor (j = 0; j \u003c n_fwnames; j++) {\n-\t\tfwreq-\u003eitems[j].path = fwnames[j].path;\n-\t\tfwnames[j].path[0] = '\\0';\n \t\t/* check if firmware path is provided by module parameter */\n \t\tif (brcmf_mp_global.firmware_path[0] != '\\0') {\n-\t\t\tstrscpy(fwnames[j].path, mp_path,\n-\t\t\t\tBRCMF_FW_NAME_LEN);\n-\n-\t\t\tif (end != '/') {\n-\t\t\t\tstrlcat(fwnames[j].path, \"/\",\n-\t\t\t\t\tBRCMF_FW_NAME_LEN);\n-\t\t\t}\n+\t\t\tsnprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, \"%s%s%s%s\",\n+\t\t\t\t mp_path, (end == '/') ? \"\" : \"/\",\n+\t\t\t\t mapping_table[i].fw_base,\n+\t\t\t\t fwnames[j].extension);\n+\t\t} else {\n+\t\t\tsnprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, \"%s%s\",\n+\t\t\t\t mapping_table[i].fw_base,\n+\t\t\t\t fwnames[j].extension);\n \t\t}\n-\t\tstrlcat(fwnames[j].path, mapping_table[i].fw_base,\n-\t\t\tBRCMF_FW_NAME_LEN);\n-\t\tstrlcat(fwnames[j].path, fwnames[j].extension,\n-\t\t\tBRCMF_FW_NAME_LEN);\n \t\tfwreq-\u003eitems[j].path = fwnames[j].path;\n \t}\n \ndiff --git a/drivers/of/fdt.c b/drivers/of/fdt.c\nindex a64afc3ded3d4..311021a83f03e 100644\n--- a/drivers/of/fdt.c\n+++ b/drivers/of/fdt.c\n@@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char *cmdline)\n \tconst void *rng_seed;\n \tconst void *fdt = initial_boot_params;\n \n+\tif (!fdt)\n+\t\tgoto handle_cmdline;\n+\n \tnode = fdt_path_offset(fdt, \"/chosen\");\n \tif (node \u003c 0)\n \t\tnode = fdt_path_offset(fdt, \"/chosen@0\");\n@@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char *cmdline)\n \t */\n #ifdef CONFIG_CMDLINE\n #if defined(CONFIG_CMDLINE_EXTEND)\n-\tstrlcat(cmdline, \" \", COMMAND_LINE_SIZE);\n-\tstrlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n+\t{\n+\t\tsize_t len = strlen(cmdline);\n+\n+\t\tif (len \u003c COMMAND_LINE_SIZE)\n+\t\t\tsnprintf(cmdline + len, COMMAND_LINE_SIZE - len, \" %s\", CONFIG_CMDLINE);\n+\t}\n #elif defined(CONFIG_CMDLINE_FORCE)\n \tstrscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n #else\ndiff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c\nindex 5ecc9ed4c44db..0d639eec689c0 100644\n--- a/drivers/pinctrl/samsung/pinctrl-samsung.c\n+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c\n@@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device *dev, struct samsung_pinctrl_dr\n \n \tbank = d-\u003epin_banks;\n \tfor (i = 0; i \u003c d-\u003enr_banks; ++i, ++bank) {\n-\t\tstrscpy(node_name, bank-\u003ename, sizeof(node_name));\n-\t\tlen = strlcat(node_name, suffix, sizeof(node_name));\n+\t\tlen = snprintf(node_name, sizeof(node_name), \"%s%s\", bank-\u003ename, suffix);\n \t\tif (len \u003e= sizeof(node_name)) {\n \t\t\tdev_err(dev, \"Too long pin bank name '%s', ignoring\\n\",\n \t\t\t\tbank-\u003ename);\ndiff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c\nindex 9b57312f43f50..9fe0343c0b321 100644\n--- a/drivers/scsi/bfa/bfa_fcs.c\n+++ b/drivers/scsi/bfa/bfa_fcs.c\n@@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s *fabric)\n \n \tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n \n-\t/* Model name/number */\n-\tstrscpy(port_cfg-\u003esym_name.symname, model,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* Driver Version */\n-\tstrlcat(port_cfg-\u003esym_name.symname, driver_info-\u003eversion,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* Host machine name */\n-\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\tdriver_info-\u003ehost_machine_name,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003esym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\n \t/*\n \t * Host OS Info :\n \t * If OS Patch Info is not there, do not truncate any bytes from the\n \t * OS name string and instead copy the entire OS info string (64 bytes).\n \t */\n \tif (driver_info-\u003ehost_os_patch[0] == '\\0') {\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_name,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n+\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t\t \"%s%s%s%s%s%s%s%s\",\n+\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);\n \t} else {\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_name,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t\t/* Append host OS Patch Info */\n-\t\tstrlcat(port_cfg-\u003esym_name.symname,\n-\t\t\tdriver_info-\u003ehost_os_patch,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n+\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t\t \"%s%s%s%s%s%s%s%s%s\",\n+\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t\t driver_info-\u003ehost_os_patch);\n \t}\n \n \t/* null terminate */\n@@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s *fabric)\n \n \tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n \n-\t/* Model name/number */\n-\tstrscpy(port_cfg-\u003enode_sym_name.symname, model,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* Driver Version */\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname, (char *)driver_info-\u003eversion,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* Host machine name */\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\tdriver_info-\u003ehost_machine_name,\n-\t\tBFA_SYMNAME_MAXLEN);\n-\tstrlcat(port_cfg-\u003enode_sym_name.symname,\n-\t\t\tBFA_FCS_PORT_SYMBNAME_SEPARATOR,\n-\t\t\tBFA_SYMNAME_MAXLEN);\n-\n-\t/* null terminate */\n-\tport_cfg-\u003enode_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;\n+\t/* Model name/number, Driver Version, Host machine name */\n+\tsnprintf(port_cfg-\u003enode_sym_name.symname, BFA_SYMNAME_MAXLEN,\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR\n+\t\t \"%s\" BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n+\t\t model, (char *)driver_info-\u003eversion,\n+\t\t driver_info-\u003ehost_machine_name);\n }\n \n /*\ndiff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c\nindex 432612d224374..a28208414aec2 100644\n--- a/fs/nfs/nfsroot.c\n+++ b/fs/nfs/nfsroot.c\n@@ -173,12 +173,15 @@ static int __init root_nfs_cat(char *dest, const char *src,\n \t\t\t       const size_t destlen)\n {\n \tsize_t len = strlen(dest);\n+\tint ret;\n \n-\tif (len \u0026\u0026 dest[len - 1] != ',')\n-\t\tif (strlcat(dest, \",\", destlen) \u003e= destlen)\n-\t\t\treturn -1;\n+\tif (len \u003e= destlen)\n+\t\treturn -1;\n+\n+\tret = snprintf(dest + len, destlen - len, \"%s%s\",\n+\t\t       (len \u0026\u0026 dest[len - 1] != ',') ? \",\" : \"\", src);\n \n-\tif (strlcat(dest, src, destlen) \u003e= destlen)\n+\tif (ret \u003c 0 || ret \u003e= destlen - len)\n \t\treturn -1;\n \treturn 0;\n }\ndiff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c\nindex 9f94919a6bc62..6e2f9887eab4b 100644\n--- a/fs/orangefs/orangefs-debugfs.c\n+++ b/fs/orangefs/orangefs-debugfs.c\n@@ -37,6 +37,7 @@\n  */\n #include \u003clinux/debugfs.h\u003e\n #include \u003clinux/slab.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n \n #include \u003clinux/uaccess.h\u003e\n \n@@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \tchar *client_title = \"Client Debug Keywords:\\n\";\n \tchar *kernel_title = \"Kernel Debug Keywords:\\n\";\n \tsize_t string_size =  DEBUG_HELP_STRING_SIZE;\n-\tsize_t result_size;\n \tsize_t i;\n \tchar *new;\n \tint rc = -EINVAL;\n+\tstruct seq_buf s;\n \n \tgossip_debug(GOSSIP_UTILS_DEBUG, \"%s: start\\n\", __func__);\n \n@@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t\tgoto out;\n \t}\n \n+\tseq_buf_init(\u0026s, new, string_size);\n+\n \t/*\n-\t * strlcat(dst, src, size) will append at most\n-\t * \"size - strlen(dst) - 1\" bytes of src onto dst,\n-\t * null terminating the result, and return the total\n-\t * length of the string it tried to create.\n-\t *\n \t * We'll just plow through here building our new debug\n-\t * help string and let strlcat take care of assuring that\n+\t * help string and let seq_buf take care of assuring that\n \t * dst doesn't overflow.\n \t */\n-\tstrlcat(new, client_title, string_size);\n+\tseq_buf_puts(\u0026s, client_title);\n \n \tif (!at_boot) {\n \n@@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t\t\tgoto out;\n \t\t}\n \n-\t\tfor (i = 0; i \u003c cdm_element_count; i++) {\n-\t\t\tstrlcat(new, \"\\t\", string_size);\n-\t\t\tstrlcat(new, cdm_array[i].keyword, string_size);\n-\t\t\tstrlcat(new, \"\\n\", string_size);\n-\t\t}\n+\t\tfor (i = 0; i \u003c cdm_element_count; i++)\n+\t\t\tseq_buf_printf(\u0026s, \"\\t%s\\n\", cdm_array[i].keyword);\n \t}\n \n-\tstrlcat(new, \"\\n\", string_size);\n-\tstrlcat(new, kernel_title, string_size);\n+\tseq_buf_puts(\u0026s, \"\\n\");\n+\tseq_buf_puts(\u0026s, kernel_title);\n \n-\tfor (i = 0; i \u003c num_kmod_keyword_mask_map; i++) {\n-\t\tstrlcat(new, \"\\t\", string_size);\n-\t\tstrlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size);\n-\t\tresult_size = strlcat(new, \"\\n\", string_size);\n-\t}\n+\tfor (i = 0; i \u003c num_kmod_keyword_mask_map; i++)\n+\t\tseq_buf_printf(\u0026s, \"\\t%s\\n\", s_kmod_keyword_mask_map[i].keyword);\n \n \t/* See if we tried to put too many bytes into \"new\"... */\n-\tif (result_size \u003e= string_size) {\n+\tif (seq_buf_has_overflowed(\u0026s)) {\n \t\tkfree(new);\n \t\tgoto out;\n \t}\n@@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot)\n \t} else {\n \t\tmutex_lock(\u0026orangefs_help_file_lock);\n \t\tmemset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE);\n-\t\tstrlcat(debug_help_string, new, string_size);\n+\t\tstrscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE);\n \t\tmutex_unlock(\u0026orangefs_help_file_lock);\n \t\tkfree(new);\n \t}\ndiff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h\nindex cf841dc71feff..0b489124bfcb8 100644\n--- a/include/linux/fortify-string.h\n+++ b/include/linux/fortify-string.h\n@@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)\n char *strcat(char * const POS p, const char *q)\n {\n \tconst size_t p_size = __member_size(p);\n-\tconst size_t wanted = strlcat(p, q, p_size);\n+\n+\tif (p_size == SIZE_MAX)\n+\t\treturn __underlying_strcat(p, q);\n+\n+\tconst size_t p_len = __fortify_strlen(p);\n+\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n \n \tif (p_size \u003c= wanted)\n \t\tfortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);\ndiff --git a/net/devlink/dev.c b/net/devlink/dev.c\nindex 55959b0ff5ab4..987b071345c41 100644\n--- a/net/devlink/dev.c\n+++ b/net/devlink/dev.c\n@@ -5,6 +5,7 @@\n  */\n \n #include \u003clinux/device.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003cnet/genetlink.h\u003e\n #include \u003cnet/sock.h\u003e\n #include \"devl_internal.h\"\n@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,\n {\n \tstruct devlink_info_req req = {};\n \tconst struct nlattr *nlattr;\n+\tstruct seq_buf s;\n \tstruct sk_buff *msg;\n \tint rem, err;\n \n@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink *devlink,\n \tif (err)\n \t\tgoto free_msg;\n \n+\tseq_buf_init(\u0026s, buf, len);\n+\ts.len = strnlen(buf, len);\n+\n \tnla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,\n \t\t\t       (void *)msg-\u003edata, msg-\u003elen, rem) {\n \t\tconst struct nlattr *kv;\n@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,\n \n \t\tnla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,\n \t\t\t\t\t nlattr, rem_kv) {\n-\t\t\tstrlcat(buf, nla_data(kv), len);\n-\t\t\tstrlcat(buf, \" \", len);\n+\t\t\tseq_buf_printf(\u0026s, \"%s \", (const char *)nla_data(kv));\n \t\t}\n \t}\n free_msg:\ndiff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c\nindex 97ff11973c493..a1e4173e5a538 100644\n--- a/net/sunrpc/addr.c\n+++ b/net/sunrpc/addr.c\n@@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton);\n  */\n char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)\n {\n-\tchar portbuf[RPCBIND_MAXUADDRPLEN];\n \tchar addrbuf[RPCBIND_MAXUADDRLEN];\n \tunsigned short port;\n+\tsize_t len;\n \n \tswitch (sap-\u003esa_family) {\n \tcase AF_INET:\n-\t\tif (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)\n+\t\tlen = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));\n+\t\tif (len == 0 || len \u003e= sizeof(addrbuf))\n \t\t\treturn NULL;\n \t\tport = ntohs(((struct sockaddr_in *)sap)-\u003esin_port);\n \t\tbreak;\n \tcase AF_INET6:\n-\t\tif (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)\n+\t\tlen = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf));\n+\t\tif (len == 0 || len \u003e= sizeof(addrbuf))\n \t\t\treturn NULL;\n \t\tport = ntohs(((struct sockaddr_in6 *)sap)-\u003esin6_port);\n \t\tbreak;\n@@ -283,11 +285,8 @@ char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)\n \t\treturn NULL;\n \t}\n \n-\tif (snprintf(portbuf, sizeof(portbuf),\n-\t\t     \".%u.%u\", port \u003e\u003e 8, port \u0026 0xff) \u003e= (int)sizeof(portbuf))\n-\t\treturn NULL;\n-\n-\tif (strlcat(addrbuf, portbuf, sizeof(addrbuf)) \u003e= sizeof(addrbuf))\n+\tif (snprintf(addrbuf + len, sizeof(addrbuf) - len,\n+\t\t     \".%u.%u\", port \u003e\u003e 8, port \u0026 0xff) \u003e= sizeof(addrbuf) - len)\n \t\treturn NULL;\n \n \treturn kstrdup(addrbuf, gfp_flags);\n@@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,\n \treturn 0;\n }\n EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);\n+\ndiff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c\nindex 0bb65be021d97..e145099ee02a9 100644\n--- a/sound/pci/ac97/ac97_codec.c\n+++ b/sound/pci/ac97/ac97_codec.c\n@@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,\n \n \tpid = look_for_codec_id(snd_ac97_codec_ids, id);\n \tif (pid) {\n-\t\tstrlcat(name, \" \", maxlen);\n-\t\tstrlcat(name, pid-\u003ename, maxlen);\n+\t\tint l = strlen(name);\n+\n \t\tif (pid-\u003emask != 0xffffffff)\n-\t\t\tsprintf(name + strlen(name), \" rev %u\", id \u0026 ~pid-\u003emask);\n+\t\t\tsnprintf(name + l, maxlen - l, \" %s rev %u\", pid-\u003ename, id \u0026 ~pid-\u003emask);\n+\t\telse\n+\t\t\tsnprintf(name + l, maxlen - l, \" %s\", pid-\u003ename);\n \t\tif (ac97 \u0026\u0026 pid-\u003epatch) {\n \t\t\tif ((modem \u0026\u0026 (pid-\u003eflags \u0026 AC97_MODEM_PATCH)) ||\n \t\t\t    (! modem \u0026\u0026 ! (pid-\u003eflags \u0026 AC97_MODEM_PATCH)))\n@@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,\n \t\t}\n \t} else {\n \t\tint l = strlen(name);\n+\n \t\tsnprintf(name + l, maxlen - l, \" id %x\", id \u0026 0xff);\n \t}\n }\ndiff --git a/sound/usb/card.c b/sound/usb/card.c\nindex 9307da95efbef..bdca8085fca66 100644\n--- a/sound/usb/card.c\n+++ b/sound/usb/card.c\n@@ -25,6 +25,7 @@\n #include \u003clinux/list.h\u003e\n #include \u003clinux/slab.h\u003e\n #include \u003clinux/string.h\u003e\n+#include \u003clinux/seq_buf.h\u003e\n #include \u003clinux/ctype.h\u003e\n #include \u003clinux/usb.h\u003e\n #include \u003clinux/moduleparam.h\u003e\n@@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device *dev,\n \tstruct snd_card *card = chip-\u003ecard;\n \tconst struct usb_audio_device_name *preset;\n \tconst char *s = NULL;\n-\tint len;\n+\tstruct seq_buf sb;\n+\tchar *buf;\n+\tsize_t size;\n \n \tpreset = lookup_device_name(chip-\u003eusb_id);\n \n@@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device *dev,\n \t\ts = preset-\u003evendor_name;\n \telse if (quirk \u0026\u0026 quirk-\u003evendor_name)\n \t\ts = quirk-\u003evendor_name;\n-\t*card-\u003elongname = 0;\n+\n+\tseq_buf_init(\u0026sb, card-\u003elongname, sizeof(card-\u003elongname));\n+\n \tif (s \u0026\u0026 *s)\n-\t\tstrscpy(card-\u003elongname, s);\n+\t\tseq_buf_puts(\u0026sb, s);\n \telse if (dev-\u003emanufacturer \u0026\u0026 *dev-\u003emanufacturer)\n-\t\tstrscpy(card-\u003elongname, dev-\u003emanufacturer);\n-\n-\tif (*card-\u003elongname) {\n-\t\tstrim(card-\u003elongname);\n-\t\tif (*card-\u003elongname)\n-\t\t\tstrlcat(card-\u003elongname, \" \", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, dev-\u003emanufacturer);\n+\n+\tif (seq_buf_used(\u0026sb)) {\n+\t\tchar *trimmed;\n+\n+\t\tseq_buf_str(\u0026sb);\n+\t\ttrimmed = strim(card-\u003elongname);\n+\t\tif (trimmed != card-\u003elongname)\n+\t\t\tmemmove(card-\u003elongname, trimmed, strlen(trimmed) + 1);\n+\t\tsb.len = strlen(card-\u003elongname);\n+\t\tif (sb.len)\n+\t\t\tseq_buf_putc(\u0026sb, ' ');\n \t}\n \n-\tstrlcat(card-\u003elongname, card-\u003eshortname, sizeof(card-\u003elongname));\n+\tseq_buf_puts(\u0026sb, card-\u003eshortname);\n \n-\tlen = strlcat(card-\u003elongname, \" at \", sizeof(card-\u003elongname));\n+\tseq_buf_puts(\u0026sb, \" at \");\n \n-\tif (len \u003c sizeof(card-\u003elongname))\n-\t\tusb_make_path(dev, card-\u003elongname + len, sizeof(card-\u003elongname) - len);\n+\tsize = seq_buf_get_buf(\u0026sb, \u0026buf);\n+\tif (size \u003e 0) {\n+\t\tint path_len = usb_make_path(dev, buf, size);\n+\n+\t\tif (path_len \u003e= 0)\n+\t\t\tseq_buf_commit(\u0026sb, path_len);\n+\t\telse\n+\t\t\tseq_buf_set_overflow(\u0026sb);\n+\t}\n \n \tswitch (snd_usb_get_speed(dev)) {\n \tcase USB_SPEED_LOW:\n-\t\tstrlcat(card-\u003elongname, \", low speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", low speed\");\n \t\tbreak;\n \tcase USB_SPEED_FULL:\n-\t\tstrlcat(card-\u003elongname, \", full speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", full speed\");\n \t\tbreak;\n \tcase USB_SPEED_HIGH:\n-\t\tstrlcat(card-\u003elongname, \", high speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", high speed\");\n \t\tbreak;\n \tcase USB_SPEED_SUPER:\n-\t\tstrlcat(card-\u003elongname, \", super speed\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", super speed\");\n \t\tbreak;\n \tcase USB_SPEED_SUPER_PLUS:\n-\t\tstrlcat(card-\u003elongname, \", super speed plus\", sizeof(card-\u003elongname));\n+\t\tseq_buf_puts(\u0026sb, \", super speed plus\");\n \t\tbreak;\n \tdefault:\n \t\tbreak;\n \t}\n+\n+\tseq_buf_str(\u0026sb);\n }\n \n static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)\ndiff --git a/sound/usb/mixer.c b/sound/usb/mixer.c\nindex ecaa8bc08d7ca..f64ecad4e77ea 100644\n--- a/sound/usb/mixer.c\n+++ b/sound/usb/mixer.c\n@@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new *snd_usb_feature_unit_ctl = \u0026usb_feature_unit_ctl;\n  */\n static size_t append_ctl_name(struct snd_kcontrol *kctl, const char *str)\n {\n-\treturn strlcat(kctl-\u003eid.name, str, sizeof(kctl-\u003eid.name));\n+\tsize_t len = strlen(kctl-\u003eid.name);\n+\n+\tif (len \u003e= sizeof(kctl-\u003eid.name))\n+\t\treturn len + strlen(str);\n+\treturn len + snprintf(kctl-\u003eid.name + len, sizeof(kctl-\u003eid.name) - len, \"%s\", str);\n }\n \n /*\n@@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer,\n \t}\n \n \tif (check_mapped_name(map, kctl-\u003eid.name, sizeof(kctl-\u003eid.name)))\n-\t\tstrlcat(kctl-\u003eid.name, \" Jack\", sizeof(kctl-\u003eid.name));\n+\t\tappend_ctl_name(kctl, \" Jack\");\n \telse\n \t\tget_connector_control_name(mixer, term, is_input, kctl-\u003eid.name,\n \t\t\t\t\t   sizeof(kctl-\u003eid.name));\n"
}

2/1

2026/09/15 11:08

agent

patch-evaluator

Model:

core

Args:

null

Results:

{
  "EnableConfigs": [
    "SND_USB_AUDIO",
    "MOUSE_SYNAPTICS_USB",
    "SUNRPC",
    "COMEDI_BOND",
    "COMEDI_MISC_DRIVERS",
    "COMEDI",
    "FORTIFY_SOURCE"
  ],
  "FocusSymbols": [
    "usb_audio_make_longname",
    "snd_usb_audio_create",
    "build_connector_control",
    "synusb_probe",
    "rpc_sockaddr2uaddr",
    "devlink_compat_running_version",
    "bonding_attach"
  ],
  "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.",
  "WorthFuzzing": true
}

Instruction:

You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.

================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.

- REACHABILITY IS THE PRIMARY GATE:
  Fuzzing can only discover bugs in code that can actually execute in standard virtualized
  environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
  If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
  regardless of whether it adds assertions or complex logic.

- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
  Patch authors routinely label changes as "cleanups", "refactorings", or state
  "No functional change intended". Do NOT take these claims at face value.
  Code refactorings that rearrange logic, introduce helper functions, or alter state management
  in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
  If reachable executable code is modified or refactored, it MUST be fuzzed.

- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
  When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
  BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
  Even if the author believes the invariant always holds, fuzzing is essential to verify whether
  an unusual sequence of operations can violate it.

================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:

- Non-kernel and non-executable changes:
  * Modifications to Documentation/, comments, or spelling fixes.
  * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
    that do not affect the compiled kernel image (vmlinux) or kernel modules.
  * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
    that do not alter control flow or data structures.
  * Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
  * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
    ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
  * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
    physical PCI hot-unplug or manual sysfs driver unbinding.
  * Code paths exclusive to architectures other than the target architecture.

================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
  * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
    BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
  * Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
  * Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
  * Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).

================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:

- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
  Do NOT list generic, ubiquitous functions called by almost every program in the corpus
  (including, but not limited to: general memory allocators and deallocators, page fault
  and trap handlers, or core synchronization primitives; this is not an exhaustive list).
  Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
  which severely dilutes fuzzing effort away from the actual changes.

- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
  List functions that specifically implement the logic being added or altered, or direct API entrypoints
  for the subsystem feature under review.

- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
  Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
  distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
  If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
  functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).

================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Prompt:

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit 7af038477662f04c34c484a45e1a571280e5f258
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Sep 15 11:08:01 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
index 4ec591bde3dfa..21140b44d96e6 100644
--- a/arch/arm/kernel/atags_parse.c
+++ b/arch/arm/kernel/atags_parse.c
@@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
 static int __init parse_tag_cmdline(const struct tag *tag)
 {
 #if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
-	strlcat(default_command_line, tag->u.cmdline.cmdline,
-		COMMAND_LINE_SIZE);
+	size_t len = strlen(default_command_line);
+
+	snprintf(default_command_line + len, COMMAND_LINE_SIZE - len,
+		 " %s", tag->u.cmdline.cmdline);
 #elif defined(CONFIG_CMDLINE_FORCE)
 	pr_warn("Ignoring tag cmdline (using the default kernel command line)\n");
 #else
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 6fa4a22a58fd6..826396f141b9c 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -33,6 +33,7 @@
 #include <linux/of_address.h>
 #include <linux/suspend.h>
 #include <linux/swiotlb.h>
+#include <linux/seq_buf.h>
 
 #include <asm/addrspace.h>
 #include <asm/alternative.h>
@@ -305,6 +306,8 @@ static void __init fdt_setup(void)
 
 static void __init bootcmdline_init(char **cmdline_p)
 {
+	struct seq_buf s;
+
 	/*
 	 * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line
 	 * is trivial - we simply use the built-in command line unconditionally &
@@ -315,6 +318,11 @@ static void __init bootcmdline_init(char **cmdline_p)
 		goto out;
 	}
 
+	/* Initialize seq_buf pointing to boot_command_line */
+	s.buffer = boot_command_line;
+	s.size = COMMAND_LINE_SIZE;
+	s.len = strlen(boot_command_line);
+
 #ifdef CONFIG_OF_FLATTREE
 	/*
 	 * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system,
@@ -323,11 +331,11 @@ static void __init bootcmdline_init(char **cmdline_p)
 	 * to boot_command_line.
 	 */
 	if (initial_boot_params) {
-		if (boot_command_line[0])
-			strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+		if (s.len)
+			seq_buf_puts(&s, " ");
 
-		if (!strstr(boot_command_line, init_command_line))
-			strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE);
+		if (!strstr(s.buffer, init_command_line))
+			seq_buf_puts(&s, init_command_line);
 
 		goto out;
 	}
@@ -338,14 +346,14 @@ static void __init bootcmdline_init(char **cmdline_p)
 	 * CONFIG_CMDLINE_EXTEND is enabled.
 	 */
 	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) && CONFIG_CMDLINE[0]) {
-		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
-		strlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+		seq_buf_puts(&s, " ");
+		seq_buf_puts(&s, CONFIG_CMDLINE);
 	}
 
 	/*
 	 * Use built-in command line if the bootloader command line is empty.
 	 */
-	if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !boot_command_line[0])
+	if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !s.len)
 		strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 
 out:
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 1ae6d0c0e1d67..0d9c2137d6758 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void)
 
 static void __init bootcmdline_append(const char *s, size_t max)
 {
+	size_t len;
+	int prec;
+
 	if (!s[0] || !max)
 		return;
 
-	if (boot_command_line[0])
-		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+	len = strlen(boot_command_line);
+	if (len >= COMMAND_LINE_SIZE - 1)
+		return;
 
-	strlcat(boot_command_line, s, max);
+	if (len) {
+		if (COMMAND_LINE_SIZE - len < 3)
+			return;
+
+		prec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2);
+		snprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, " %.*s",
+			 prec, s);
+	} else {
+		prec = min_t(size_t, max, COMMAND_LINE_SIZE - 1);
+		snprintf(boot_command_line, COMMAND_LINE_SIZE, "%.*s",
+			 prec, s);
+	}
 }
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index d3e17a7a89016..fa3efc82ad874 100644
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/console.h>
 #include <linux/seq_file.h>
+#include <linux/seq_buf.h>
 #define PCI_DEBUG
 #include <linux/pci.h>
 #undef PCI_DEBUG
@@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE];
 static void __init setup_cmdline(char **cmdline_p)
 {
 	extern unsigned int boot_args[];
+	struct seq_buf s;
 	char *p;
 
 	*cmdline_p = command_line;
@@ -54,19 +56,21 @@ static void __init setup_cmdline(char **cmdline_p)
 	strscpy(boot_command_line, (char *)__va(boot_args[1]),
 		COMMAND_LINE_SIZE);
 
+	s.buffer = boot_command_line;
+	s.size = COMMAND_LINE_SIZE;
+	s.len = strlen(boot_command_line);
+
 	/* autodetect console type (if not done by palo yet) */
 	p = boot_command_line;
 	if (!str_has_prefix(p, "console=") && !strstr(p, " console=")) {
-		strlcat(p, " console=", COMMAND_LINE_SIZE);
-		if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
-			strlcat(p, "ttyS0", COMMAND_LINE_SIZE);
-		else
-			strlcat(p, "tty0", COMMAND_LINE_SIZE);
+		seq_buf_printf(&s, " console=%s",
+			       PAGE0->mem_cons.cl_class == CL_DUPLEX ?
+			       "ttyS0" : "tty0");
 	}
 
 	/* default to use early console */
 	if (!strstr(p, "earlycon"))
-		strlcat(p, " earlycon=pdc", COMMAND_LINE_SIZE);
+		seq_buf_printf(&s, " earlycon=pdc");
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* did palo pass us a ramdisk? */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index cda6adb9f69c4..c40e0edd7c136 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -916,9 +916,11 @@ void __init setup_arch(char **cmdline_p)
 #else
 	if (builtin_cmdline[0]) {
 		/* append boot loader cmdline to builtin */
-		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
-		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
-		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+		char tmp[COMMAND_LINE_SIZE];
+
+		snprintf(tmp, COMMAND_LINE_SIZE, "%s %s", builtin_cmdline, boot_command_line);
+		strscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE);
+		strscpy(boot_command_line, tmp, COMMAND_LINE_SIZE);
 	}
 #endif
 	builtin_cmdline_added = true;
diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
index 8e10ecab4f0dc..a10cfbd04c728 100644
--- a/drivers/comedi/drivers/comedi_bond.c
+++ b/drivers/comedi/drivers/comedi_bond.c
@@ -39,6 +39,7 @@
 
 #include <linux/module.h>
 #include <linux/string.h>
+#include <linux/seq_buf.h>
 #include <linux/slab.h>
 #include <linux/comedi.h>
 #include <linux/comedi/comedilib.h>
@@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 {
 	struct comedi_bond_private *devpriv = dev->private;
 	DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
+	struct seq_buf s;
 	int i;
 
 	memset(&devs_opened, 0, sizeof(devs_opened));
-	devpriv->name[0] = 0;
+	seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
 	/*
 	 * Loop through all comedi devices specified on the command-line,
 	 * building our device list.
@@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 			}
 			devpriv->devs = devs;
 			devpriv->devs[devpriv->ndevs++] = bdev;
-			{
-				/* Append dev:subdev to devpriv->name */
-				char buf[20];
-
-				snprintf(buf, sizeof(buf), "%u:%u ",
-					 bdev->minor, bdev->subdev);
-				strlcat(devpriv->name, buf,
-					sizeof(devpriv->name));
-			}
+
+			/* Append dev:subdev to devpriv->name */
+			seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
 		}
 	}
 
@@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 		return -EINVAL;
 	}
 
+	seq_buf_str(&s);
+
 	return 0;
 }
 
diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index 9c0a1e48f96f2..4e3781815b6d7 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/bitfield.h>
 #include <linux/circ_buf.h>
+#include <linux/seq_buf.h>
 
 #include <asm/page.h>
 
@@ -47,12 +48,17 @@ static void decode_register(char *str, size_t size,
 {
 	int ret = 0;
 
+	if (size > 0)
+		str[0] = '\0';
+
 	while (descr->type && descr->mask && descr->descr) {
 		if (reg & descr->mask) {
 			ret = snprintf(str, size, "\n\t%s, %s",
 				       descr->type == ERR_CORRECTED ?
 					 "Corrected" : "Uncorrected",
 				       descr->descr);
+			if (ret < 0 || ret >= size)
+				break;
 			str += ret;
 			size -= ret;
 		}
@@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(ocx->com_ring_head, ocx->com_ring_tail,
 			ARRAY_SIZE(ocx->com_err_ctx))) {
+		struct seq_buf s;
+
 		tail = ring_pos(ocx->com_ring_tail,
 				ARRAY_SIZE(ocx->com_err_ctx));
 		ctx = &ocx->com_err_ctx[tail];
 
-		snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx",
-			ocx->edac_dev->ctl_name, ctx->reg_com_int);
+		seq_buf_init(&s, msg, OCX_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx",
+			       ocx->edac_dev->ctl_name, ctx->reg_com_int);
 
 		decode_register(other, OCX_OTHER_SIZE,
 				ocx_com_errors, ctx->reg_com_int);
 
-		strlcat(msg, other, OCX_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		for (lane = 0; lane < OCX_RX_LANES; lane++)
 			if (ctx->reg_com_int & BIT(lane)) {
-				snprintf(other, OCX_OTHER_SIZE,
-					 "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx",
-					 lane, ctx->reg_lane_int[lane],
-					 lane, ctx->reg_lane_stat11[lane]);
-
-				strlcat(msg, other, OCX_MESSAGE_SIZE);
+				seq_buf_printf(&s,
+					       "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx",
+					       lane, ctx->reg_lane_int[lane],
+					       lane, ctx->reg_lane_stat11[lane]);
 
 				decode_register(other, OCX_OTHER_SIZE,
 						ocx_lane_errors,
 						ctx->reg_lane_int[lane]);
-				strlcat(msg, other, OCX_MESSAGE_SIZE);
+				seq_buf_puts(&s, other);
 			}
 
 		if (ctx->reg_com_int & OCX_COM_INT_CE)
-			edac_device_handle_ce(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 
 		ocx->com_ring_tail++;
 	}
@@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(ocx->link_ring_head, ocx->link_ring_tail,
 			ARRAY_SIZE(ocx->link_err_ctx))) {
+		struct seq_buf s;
+
 		tail = ring_pos(ocx->link_ring_head,
 				ARRAY_SIZE(ocx->link_err_ctx));
 
 		ctx = &ocx->link_err_ctx[tail];
 
-		snprintf(msg, OCX_MESSAGE_SIZE,
-			 "%s: OCX_COM_LINK_INT[%d]: %016llx",
-			 ocx->edac_dev->ctl_name,
-			 ctx->link, ctx->reg_com_link_int);
+		seq_buf_init(&s, msg, OCX_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: OCX_COM_LINK_INT[%d]: %016llx",
+			       ocx->edac_dev->ctl_name,
+			       ctx->link, ctx->reg_com_link_int);
 
 		decode_register(other, OCX_OTHER_SIZE,
 				ocx_com_link_errors, ctx->reg_com_link_int);
 
-		strlcat(msg, other, OCX_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		if (ctx->reg_com_link_int & OCX_COM_LINK_INT_UE)
-			edac_device_handle_ue(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ue(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 		else if (ctx->reg_com_link_int & OCX_COM_LINK_INT_CE)
-			edac_device_handle_ce(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 
 		ocx->link_ring_tail++;
 	}
@@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(l2c->ring_head, l2c->ring_tail,
 			ARRAY_SIZE(l2c->err_ctx))) {
-		snprintf(msg, L2C_MESSAGE_SIZE,
-			 "%s: %s: %016llx, %s: %016llx",
-			 l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int,
-			 ctx->reg_ext_name, ctx->reg_ext);
+		struct seq_buf s;
+
+		tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx));
+		ctx = &l2c->err_ctx[tail];
+
+		seq_buf_init(&s, msg, L2C_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: %s: %016llx, %s: %016llx",
+			       l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int,
+			       ctx->reg_ext_name, ctx->reg_ext);
 
 		decode_register(other, L2C_OTHER_SIZE, l2_errors, ctx->reg_int);
 
-		strlcat(msg, other, L2C_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		if (ctx->reg_int & mask_ue)
-			edac_device_handle_ue(l2c->edac_dev, 0, 0, msg);
+			edac_device_handle_ue(l2c->edac_dev, 0, 0, seq_buf_str(&s));
 		else if (ctx->reg_int & mask_ce)
-			edac_device_handle_ce(l2c->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(l2c->edac_dev, 0, 0, seq_buf_str(&s));
 
 		l2c->ring_tail++;
 	}
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 7ce9e212770ad..229b5fec44bff 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -29,6 +29,7 @@
 #include <linux/kernel.h>
 #include <linux/random.h>
 #include <linux/sched.h>
+#include <linux/seq_buf.h>
 #include <linux/seq_file.h>
 
 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
@@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
 				char *proppath,
 				size_t proppath_size)
 {
+	struct seq_buf s;
 	int i;
-	char temp[8];
 
-	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
+	seq_buf_init(&s, proppath, proppath_size);
+
+	seq_buf_printf(&s, "mst:%d", mstb->mgr->conn_base_id);
 	for (i = 0; i < (mstb->lct - 1); i++) {
 		int shift = (i % 2) ? 0 : 4;
 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
 
-		snprintf(temp, sizeof(temp), "-%d", port_num);
-		strlcat(proppath, temp, proppath_size);
+		seq_buf_printf(&s, "-%d", port_num);
 	}
-	snprintf(temp, sizeof(temp), "-%d", pnum);
-	strlcat(proppath, temp, proppath_size);
+	seq_buf_printf(&s, "-%d", pnum);
+
+	seq_buf_str(&s);
 }
 
 /**
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
index 0f242db775e1c..548a50f744224 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/seq_buf.h>
 
 #include <drm/drm_print.h>
 #include <drm/drm_debugfs.h>
@@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 	char engines[128];
+	struct seq_buf s;
+	const char *s_str;
 
-	engines[0] = '\0';
+	seq_buf_init(&s, engines, sizeof(engines));
 
 	if (group < num_groups) {
 		for_each_hw_engine(hwe, gt, id) {
@@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 			u16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe);
 			u32 mask = groups[group].engines[guc_class];
 
-			if (mask & BIT(guc_logical_instance)) {
-				strlcat(engines, hwe->name, sizeof(engines));
-				strlcat(engines, " ", sizeof(engines));
-			}
+			if (mask & BIT(guc_logical_instance))
+				seq_buf_printf(&s, "%s ", hwe->name);
 		}
-		strlcat(engines, "\n", sizeof(engines));
+		seq_buf_puts(&s, "\n");
 	}
 
-	return simple_read_from_buffer(buf, count, ppos, engines, strlen(engines));
+	s_str = seq_buf_str(&s);
+	return simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));
 }
 
 static const struct file_operations sched_group_engines_fops = {
@@ -663,15 +665,15 @@ static ssize_t control_write(struct file *file, const char __user *buf, size_t c
 static ssize_t control_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	char help[128];
+	struct seq_buf s;
 	size_t n;
 
-	help[0] = '\0';
+	seq_buf_init(&s, help, sizeof(help));
 	for (n = 0; n < ARRAY_SIZE(control_cmds); n++) {
-		strlcat(help, control_cmds[n].cmd, sizeof(help));
-		strlcat(help, "\n", sizeof(help));
+		seq_buf_printf(&s, "%s\n", control_cmds[n].cmd);
 	}
 
-	return simple_read_from_buffer(buf, count, ppos, help, strlen(help));
+	return simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s));
 }
 
 static const struct file_operations control_ops = {
diff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c
index 880a0c79148cd..d13d2d6202ee5 100644
--- a/drivers/input/mouse/synaptics_usb.c
+++ b/drivers/input/mouse/synaptics_usb.c
@@ -41,6 +41,7 @@
 #include <linux/usb.h>
 #include <linux/input.h>
 #include <linux/usb/input.h>
+#include <linux/seq_buf.h>
 
 #define USB_VENDOR_ID_SYNAPTICS	0x06cb
 #define USB_DEVICE_ID_SYNAPTICS_TP	0x0001	/* Synaptics USB TouchPad */
@@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface *intf,
 	struct input_dev *input_dev;
 	unsigned int intf_num = intf->cur_altsetting->desc.bInterfaceNumber;
 	unsigned int altsetting = min(intf->num_altsetting, 1U);
+	struct seq_buf s;
+	char path[64];
 	int error;
 
 	error = usb_set_interface(udev, intf_num, altsetting);
@@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface *intf,
 			 ep->bInterval);
 	synusb->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 
+	seq_buf_init(&s, synusb->name, sizeof(synusb->name));
+
 	if (udev->manufacturer)
-		strscpy(synusb->name, udev->manufacturer,
-			sizeof(synusb->name));
+		seq_buf_puts(&s, udev->manufacturer);
 
 	if (udev->product) {
 		if (udev->manufacturer)
-			strlcat(synusb->name, " ", sizeof(synusb->name));
-		strlcat(synusb->name, udev->product, sizeof(synusb->name));
+			seq_buf_puts(&s, " ");
+		seq_buf_puts(&s, udev->product);
 	}
 
-	if (!strlen(synusb->name))
-		snprintf(synusb->name, sizeof(synusb->name),
-			 "USB Synaptics Device %04x:%04x",
-			 le16_to_cpu(udev->descriptor.idVendor),
-			 le16_to_cpu(udev->descriptor.idProduct));
+	if (!seq_buf_used(&s))
+		seq_buf_printf(&s, "USB Synaptics Device %04x:%04x",
+			       le16_to_cpu(udev->descriptor.idVendor),
+			       le16_to_cpu(udev->descriptor.idProduct));
 
 	if (synusb->flags & SYNUSB_STICK)
-		strlcat(synusb->name, " (Stick)", sizeof(synusb->name));
+		seq_buf_puts(&s, " (Stick)");
+
+	seq_buf_str(&s);
 
-	usb_make_path(udev, synusb->phys, sizeof(synusb->phys));
-	strlcat(synusb->phys, "/input0", sizeof(synusb->phys));
+	usb_make_path(udev, path, sizeof(path));
+	snprintf(synusb->phys, sizeof(synusb->phys), "%s/input0", path);
 
 	input_dev->name = synusb->name;
 	input_dev->phys = synusb->phys;
diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
index f1241b63aa5ce..bd15eb58fc84f 100644
--- a/drivers/media/dvb-frontends/si2165.c
+++ b/drivers/media/dvb-frontends/si2165.c
@@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client *client)
 		chip_name, rev_char, state->chip_type,
 		state->chip_revcode);
 
-	strlcat(state->fe.ops.info.name, chip_name,
-		sizeof(state->fe.ops.info.name));
+	snprintf(state->fe.ops.info.name, sizeof(state->fe.ops.info.name),
+		 "Silicon Labs %s%s%s",
+		 chip_name,
+		 state->has_dvbt ? " DVB-T" : "",
+		 state->has_dvbc ? " DVB-C" : "");
 
 	n = 0;
-	if (state->has_dvbt) {
+	if (state->has_dvbt)
 		state->fe.ops.delsys[n++] = SYS_DVBT;
-		strlcat(state->fe.ops.info.name, " DVB-T",
-			sizeof(state->fe.ops.info.name));
-	}
-	if (state->has_dvbc) {
+	if (state->has_dvbc)
 		state->fe.ops.delsys[n++] = SYS_DVBC_ANNEX_A;
-		strlcat(state->fe.ops.info.name, " DVB-C",
-			sizeof(state->fe.ops.info.name));
-	}
 
 	/* return fe pointer */
 	*pdata->fe = &state->fe;
diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index 1b6a8fbaa6485..9f792128a0efe 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -1059,19 +1059,26 @@ static inline char *i40e_nvm_version_str(struct i40e_hw *hw, char *buf,
 					 size_t len)
 {
 	char ver[16] = " ";
+	size_t offset;
 
 	/* Get NVM version */
 	i40e_info_nvm_ver(hw, buf, len);
 
 	/* Append EETrackID if provided */
 	i40e_info_eetrack(hw, &ver[1], sizeof(ver) - 1);
-	if (strlen(ver) > 1)
-		strlcat(buf, ver, len);
+	if (strlen(ver) > 1) {
+		offset = strlen(buf);
+		if (offset < len)
+			snprintf(buf + offset, len - offset, "%s", ver);
+	}
 
 	/* Append combo image version if provided */
 	i40e_info_civd_ver(hw, &ver[1], sizeof(ver) - 1);
-	if (strlen(ver) > 1)
-		strlcat(buf, ver, len);
+	if (strlen(ver) > 1) {
+		offset = strlen(buf);
+		if (offset < len)
+			snprintf(buf + offset, len - offset, "%s", ver);
+	}
 
 	return buf;
 }
diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c
index 479b2418ca340..fcc9e9eb57322 100644
--- a/drivers/net/wireless/ath/wil6210/wmi.c
+++ b/drivers/net/wireless/ath/wil6210/wmi.c
@@ -7,6 +7,7 @@
 #include <linux/moduleparam.h>
 #include <linux/etherdevice.h>
 #include <linux/if_arp.h>
+#include <linux/seq_buf.h>
 
 #include "wil6210.h"
 #include "txrx.h"
@@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv *wil)
 
 static void resume_triggers2string(u32 triggers, char *string, int str_size)
 {
-	string[0] = '\0';
+	struct seq_buf s;
+
+	seq_buf_init(&s, string, str_size);
 
 	if (!triggers) {
-		strlcat(string, " UNKNOWN", str_size);
-		return;
-	}
+		seq_buf_puts(&s, " UNKNOWN");
+	} else {
+		if (triggers & WMI_RESUME_TRIGGER_HOST)
+			seq_buf_puts(&s, " HOST");
 
-	if (triggers & WMI_RESUME_TRIGGER_HOST)
-		strlcat(string, " HOST", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_UCAST_RX)
+			seq_buf_puts(&s, " UCAST_RX");
 
-	if (triggers & WMI_RESUME_TRIGGER_UCAST_RX)
-		strlcat(string, " UCAST_RX", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_BCAST_RX)
+			seq_buf_puts(&s, " BCAST_RX");
 
-	if (triggers & WMI_RESUME_TRIGGER_BCAST_RX)
-		strlcat(string, " BCAST_RX", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_WMI_EVT)
+			seq_buf_puts(&s, " WMI_EVT");
 
-	if (triggers & WMI_RESUME_TRIGGER_WMI_EVT)
-		strlcat(string, " WMI_EVT", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_DISCONNECT)
+			seq_buf_puts(&s, " DISCONNECT");
+	}
 
-	if (triggers & WMI_RESUME_TRIGGER_DISCONNECT)
-		strlcat(string, " DISCONNECT", str_size);
+	seq_buf_str(&s);
 }
 
 int wmi_resume(struct wil6210_priv *wil)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index 22ff326f1924a..2f74a952599ec 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
@@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev,
 	fwreq->n_items = n_fwnames;
 
 	for (j = 0; j < n_fwnames; j++) {
-		fwreq->items[j].path = fwnames[j].path;
-		fwnames[j].path[0] = '\0';
 		/* check if firmware path is provided by module parameter */
 		if (brcmf_mp_global.firmware_path[0] != '\0') {
-			strscpy(fwnames[j].path, mp_path,
-				BRCMF_FW_NAME_LEN);
-
-			if (end != '/') {
-				strlcat(fwnames[j].path, "/",
-					BRCMF_FW_NAME_LEN);
-			}
+			snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s",
+				 mp_path, (end == '/') ? "" : "/",
+				 mapping_table[i].fw_base,
+				 fwnames[j].extension);
+		} else {
+			snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s",
+				 mapping_table[i].fw_base,
+				 fwnames[j].extension);
 		}
-		strlcat(fwnames[j].path, mapping_table[i].fw_base,
-			BRCMF_FW_NAME_LEN);
-		strlcat(fwnames[j].path, fwnames[j].extension,
-			BRCMF_FW_NAME_LEN);
 		fwreq->items[j].path = fwnames[j].path;
 	}
 
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index a64afc3ded3d4..311021a83f03e 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 	const void *rng_seed;
 	const void *fdt = initial_boot_params;
 
+	if (!fdt)
+		goto handle_cmdline;
+
 	node = fdt_path_offset(fdt, "/chosen");
 	if (node < 0)
 		node = fdt_path_offset(fdt, "/chosen@0");
@@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 	 */
 #ifdef CONFIG_CMDLINE
 #if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
-	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+	{
+		size_t len = strlen(cmdline);
+
+		if (len < COMMAND_LINE_SIZE)
+			snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE);
+	}
 #elif defined(CONFIG_CMDLINE_FORCE)
 	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #else
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
index 5ecc9ed4c44db..0d639eec689c0 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.c
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
@@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device *dev, struct samsung_pinctrl_dr
 
 	bank = d->pin_banks;
 	for (i = 0; i < d->nr_banks; ++i, ++bank) {
-		strscpy(node_name, bank->name, sizeof(node_name));
-		len = strlcat(node_name, suffix, sizeof(node_name));
+		len = snprintf(node_name, sizeof(node_name), "%s%s", bank->name, suffix);
 		if (len >= sizeof(node_name)) {
 			dev_err(dev, "Too long pin bank name '%s', ignoring\n",
 				bank->name);
diff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c
index 9b57312f43f50..9fe0343c0b321 100644
--- a/drivers/scsi/bfa/bfa_fcs.c
+++ b/drivers/scsi/bfa/bfa_fcs.c
@@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s *fabric)
 
 	bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model);
 
-	/* Model name/number */
-	strscpy(port_cfg->sym_name.symname, model,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
-	/* Driver Version */
-	strlcat(port_cfg->sym_name.symname, driver_info->version,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
-	/* Host machine name */
-	strlcat(port_cfg->sym_name.symname,
-		driver_info->host_machine_name,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
 	/*
 	 * Host OS Info :
 	 * If OS Patch Info is not there, do not truncate any bytes from the
 	 * OS name string and instead copy the entire OS info string (64 bytes).
 	 */
 	if (driver_info->host_os_patch[0] == '\0') {
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_name,
-			BFA_SYMNAME_MAXLEN);
-		strlcat(port_cfg->sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
+		snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN,
+			 "%s%s%s%s%s%s%s%s",
+			 model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);
 	} else {
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_name,
-			BFA_SYMNAME_MAXLEN);
-		strlcat(port_cfg->sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-		/* Append host OS Patch Info */
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_patch,
-			BFA_SYMNAME_MAXLEN);
+		snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN,
+			 "%s%s%s%s%s%s%s%s%s",
+			 model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_patch);
 	}
 
 	/* null terminate */
@@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s *fabric)
 
 	bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model);
 
-	/* Model name/number */
-	strscpy(port_cfg->node_sym_name.symname, model,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* Driver Version */
-	strlcat(port_cfg->node_sym_name.symname, (char *)driver_info->version,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* Host machine name */
-	strlcat(port_cfg->node_sym_name.symname,
-		driver_info->host_machine_name,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* null terminate */
-	port_cfg->node_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;
+	/* Model name/number, Driver Version, Host machine name */
+	snprintf(port_cfg->node_sym_name.symname, BFA_SYMNAME_MAXLEN,
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+		 model, (char *)driver_info->version,
+		 driver_info->host_machine_name);
 }
 
 /*
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 432612d224374..a28208414aec2 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -173,12 +173,15 @@ static int __init root_nfs_cat(char *dest, const char *src,
 			       const size_t destlen)
 {
 	size_t len = strlen(dest);
+	int ret;
 
-	if (len && dest[len - 1] != ',')
-		if (strlcat(dest, ",", destlen) >= destlen)
-			return -1;
+	if (len >= destlen)
+		return -1;
+
+	ret = snprintf(dest + len, destlen - len, "%s%s",
+		       (len && dest[len - 1] != ',') ? "," : "", src);
 
-	if (strlcat(dest, src, destlen) >= destlen)
+	if (ret < 0 || ret >= destlen - len)
 		return -1;
 	return 0;
 }
diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c
index 9f94919a6bc62..6e2f9887eab4b 100644
--- a/fs/orangefs/orangefs-debugfs.c
+++ b/fs/orangefs/orangefs-debugfs.c
@@ -37,6 +37,7 @@
  */
 #include <linux/debugfs.h>
 #include <linux/slab.h>
+#include <linux/seq_buf.h>
 
 #include <linux/uaccess.h>
 
@@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 	char *client_title = "Client Debug Keywords:\n";
 	char *kernel_title = "Kernel Debug Keywords:\n";
 	size_t string_size =  DEBUG_HELP_STRING_SIZE;
-	size_t result_size;
 	size_t i;
 	char *new;
 	int rc = -EINVAL;
+	struct seq_buf s;
 
 	gossip_debug(GOSSIP_UTILS_DEBUG, "%s: start\n", __func__);
 
@@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 		goto out;
 	}
 
+	seq_buf_init(&s, new, string_size);
+
 	/*
-	 * strlcat(dst, src, size) will append at most
-	 * "size - strlen(dst) - 1" bytes of src onto dst,
-	 * null terminating the result, and return the total
-	 * length of the string it tried to create.
-	 *
 	 * We'll just plow through here building our new debug
-	 * help string and let strlcat take care of assuring that
+	 * help string and let seq_buf take care of assuring that
 	 * dst doesn't overflow.
 	 */
-	strlcat(new, client_title, string_size);
+	seq_buf_puts(&s, client_title);
 
 	if (!at_boot) {
 
@@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 			goto out;
 		}
 
-		for (i = 0; i < cdm_element_count; i++) {
-			strlcat(new, "\t", string_size);
-			strlcat(new, cdm_array[i].keyword, string_size);
-			strlcat(new, "\n", string_size);
-		}
+		for (i = 0; i < cdm_element_count; i++)
+			seq_buf_printf(&s, "\t%s\n", cdm_array[i].keyword);
 	}
 
-	strlcat(new, "\n", string_size);
-	strlcat(new, kernel_title, string_size);
+	seq_buf_puts(&s, "\n");
+	seq_buf_puts(&s, kernel_title);
 
-	for (i = 0; i < num_kmod_keyword_mask_map; i++) {
-		strlcat(new, "\t", string_size);
-		strlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size);
-		result_size = strlcat(new, "\n", string_size);
-	}
+	for (i = 0; i < num_kmod_keyword_mask_map; i++)
+		seq_buf_printf(&s, "\t%s\n", s_kmod_keyword_mask_map[i].keyword);
 
 	/* See if we tried to put too many bytes into "new"... */
-	if (result_size >= string_size) {
+	if (seq_buf_has_overflowed(&s)) {
 		kfree(new);
 		goto out;
 	}
@@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 	} else {
 		mutex_lock(&orangefs_help_file_lock);
 		memset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE);
-		strlcat(debug_help_string, new, string_size);
+		strscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE);
 		mutex_unlock(&orangefs_help_file_lock);
 		kfree(new);
 	}
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index cf841dc71feff..0b489124bfcb8 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
 char *strcat(char * const POS p, const char *q)
 {
 	const size_t p_size = __member_size(p);
-	const size_t wanted = strlcat(p, q, p_size);
+
+	if (p_size == SIZE_MAX)
+		return __underlying_strcat(p, q);
+
+	const size_t p_len = __fortify_strlen(p);
+	const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q);
 
 	if (p_size <= wanted)
 		fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);
diff --git a/net/devlink/dev.c b/net/devlink/dev.c
index 55959b0ff5ab4..987b071345c41 100644
--- a/net/devlink/dev.c
+++ b/net/devlink/dev.c
@@ -5,6 +5,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/seq_buf.h>
 #include <net/genetlink.h>
 #include <net/sock.h>
 #include "devl_internal.h"
@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 {
 	struct devlink_info_req req = {};
 	const struct nlattr *nlattr;
+	struct seq_buf s;
 	struct sk_buff *msg;
 	int rem, err;
 
@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 	if (err)
 		goto free_msg;
 
+	seq_buf_init(&s, buf, len);
+	s.len = strnlen(buf, len);
+
 	nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,
 			       (void *)msg->data, msg->len, rem) {
 		const struct nlattr *kv;
@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 
 		nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,
 					 nlattr, rem_kv) {
-			strlcat(buf, nla_data(kv), len);
-			strlcat(buf, " ", len);
+			seq_buf_printf(&s, "%s ", (const char *)nla_data(kv));
 		}
 	}
 free_msg:
diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c
index 97ff11973c493..a1e4173e5a538 100644
--- a/net/sunrpc/addr.c
+++ b/net/sunrpc/addr.c
@@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton);
  */
 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 {
-	char portbuf[RPCBIND_MAXUADDRPLEN];
 	char addrbuf[RPCBIND_MAXUADDRLEN];
 	unsigned short port;
+	size_t len;
 
 	switch (sap->sa_family) {
 	case AF_INET:
-		if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
+		len = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));
+		if (len == 0 || len >= sizeof(addrbuf))
 			return NULL;
 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
 		break;
 	case AF_INET6:
-		if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
+		len = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf));
+		if (len == 0 || len >= sizeof(addrbuf))
 			return NULL;
 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 		break;
@@ -283,11 +285,8 @@ char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 		return NULL;
 	}
 
-	if (snprintf(portbuf, sizeof(portbuf),
-		     ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf))
-		return NULL;
-
-	if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf))
+	if (snprintf(addrbuf + len, sizeof(addrbuf) - len,
+		     ".%u.%u", port >> 8, port & 0xff) >= sizeof(addrbuf) - len)
 		return NULL;
 
 	return kstrdup(addrbuf, gfp_flags);
@@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);
+
diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
index 0bb65be021d97..e145099ee02a9 100644
--- a/sound/pci/ac97/ac97_codec.c
+++ b/sound/pci/ac97/ac97_codec.c
@@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,
 
 	pid = look_for_codec_id(snd_ac97_codec_ids, id);
 	if (pid) {
-		strlcat(name, " ", maxlen);
-		strlcat(name, pid->name, maxlen);
+		int l = strlen(name);
+
 		if (pid->mask != 0xffffffff)
-			sprintf(name + strlen(name), " rev %u", id & ~pid->mask);
+			snprintf(name + l, maxlen - l, " %s rev %u", pid->name, id & ~pid->mask);
+		else
+			snprintf(name + l, maxlen - l, " %s", pid->name);
 		if (ac97 && pid->patch) {
 			if ((modem && (pid->flags & AC97_MODEM_PATCH)) ||
 			    (! modem && ! (pid->flags & AC97_MODEM_PATCH)))
@@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,
 		}
 	} else {
 		int l = strlen(name);
+
 		snprintf(name + l, maxlen - l, " id %x", id & 0xff);
 	}
 }
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 9307da95efbef..bdca8085fca66 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -25,6 +25,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/seq_buf.h>
 #include <linux/ctype.h>
 #include <linux/usb.h>
 #include <linux/moduleparam.h>
@@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device *dev,
 	struct snd_card *card = chip->card;
 	const struct usb_audio_device_name *preset;
 	const char *s = NULL;
-	int len;
+	struct seq_buf sb;
+	char *buf;
+	size_t size;
 
 	preset = lookup_device_name(chip->usb_id);
 
@@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device *dev,
 		s = preset->vendor_name;
 	else if (quirk && quirk->vendor_name)
 		s = quirk->vendor_name;
-	*card->longname = 0;
+
+	seq_buf_init(&sb, card->longname, sizeof(card->longname));
+
 	if (s && *s)
-		strscpy(card->longname, s);
+		seq_buf_puts(&sb, s);
 	else if (dev->manufacturer && *dev->manufacturer)
-		strscpy(card->longname, dev->manufacturer);
-
-	if (*card->longname) {
-		strim(card->longname);
-		if (*card->longname)
-			strlcat(card->longname, " ", sizeof(card->longname));
+		seq_buf_puts(&sb, dev->manufacturer);
+
+	if (seq_buf_used(&sb)) {
+		char *trimmed;
+
+		seq_buf_str(&sb);
+		trimmed = strim(card->longname);
+		if (trimmed != card->longname)
+			memmove(card->longname, trimmed, strlen(trimmed) + 1);
+		sb.len = strlen(card->longname);
+		if (sb.len)
+			seq_buf_putc(&sb, ' ');
 	}
 
-	strlcat(card->longname, card->shortname, sizeof(card->longname));
+	seq_buf_puts(&sb, card->shortname);
 
-	len = strlcat(card->longname, " at ", sizeof(card->longname));
+	seq_buf_puts(&sb, " at ");
 
-	if (len < sizeof(card->longname))
-		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
+	size = seq_buf_get_buf(&sb, &buf);
+	if (size > 0) {
+		int path_len = usb_make_path(dev, buf, size);
+
+		if (path_len >= 0)
+			seq_buf_commit(&sb, path_len);
+		else
+			seq_buf_set_overflow(&sb);
+	}
 
 	switch (snd_usb_get_speed(dev)) {
 	case USB_SPEED_LOW:
-		strlcat(card->longname, ", low speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", low speed");
 		break;
 	case USB_SPEED_FULL:
-		strlcat(card->longname, ", full speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", full speed");
 		break;
 	case USB_SPEED_HIGH:
-		strlcat(card->longname, ", high speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", high speed");
 		break;
 	case USB_SPEED_SUPER:
-		strlcat(card->longname, ", super speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", super speed");
 		break;
 	case USB_SPEED_SUPER_PLUS:
-		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
+		seq_buf_puts(&sb, ", super speed plus");
 		break;
 	default:
 		break;
 	}
+
+	seq_buf_str(&sb);
 }
 
 static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ecaa8bc08d7ca..f64ecad4e77ea 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
  */
 static size_t append_ctl_name(struct snd_kcontrol *kctl, const char *str)
 {
-	return strlcat(kctl->id.name, str, sizeof(kctl->id.name));
+	size_t len = strlen(kctl->id.name);
+
+	if (len >= sizeof(kctl->id.name))
+		return len + strlen(str);
+	return len + snprintf(kctl->id.name + len, sizeof(kctl->id.name) - len, "%s", str);
 }
 
 /*
@@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer,
 	}
 
 	if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name)))
-		strlcat(kctl->id.name, " Jack", sizeof(kctl->id.name));
+		append_ctl_name(kctl, " Jack");
 	else
 		get_connector_control_name(mixer, term, is_input, kctl->id.name,
 					   sizeof(kctl->id.name));

3/2

2026/09/15 11:08

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 20696
							output: 21
							thoughts: 2291

Thoughts:

**Fuzzing Decision for the Commit**

Okay, here's the breakdown. The task is to determine if this commit warrants fuzzing with syzkaller, given the instructions and the target architecture (amd64). Let's start by considering the patch in the abstract, and then reviewing specific components.

First, I see the core change is replacing instances of `strlcat()` which is probably happening as part of the effort to deprecate `strlcat()` in the kernel.

Now, let's look at the affected files.

*   **Architecture-Specific Files (ARM, Loongarch, MIPS, PARISC, x86):** These are generally out since the target is amd64, although there might be corner cases I'll have to investigate if they might be called during early boot. I see x86's setup arch is called at boot, which is probably not fuzzable via syscalls.

*   **Drivers:** This is where things get interesting. The instructions point us towards reachable drivers accessible via virtual buses, which includes virtio, USB gadget, loopback, etc.
    *   `drivers/comedi/drivers/comedi_bond.c` looks like comedi, which I'm not sure about. I need to check if comedi devices can be created or configured via ioctl (specifically in `do_dev_config`).
    *   `drivers/input/mouse/synaptics_usb.c` uses `synusb_probe()`. This *is* reachable via USB emulation in syzkaller.
    *   `drivers/gpu/drm/display/drm_dp_mst_topology.c` and `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c` are Intel graphics related. This is less clear whether they can be effectively reached through syzkaller.
    *   `drivers/net/ethernet/intel/i40e/i40e.h`, `drivers/net/wireless/ath/wil6210/wmi.c`, `drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c` are network-related drivers.
    *   `drivers/scsi/bfa/bfa_fcs.c` is a Fibre Channel HBA driver, probably not reachable.
    *   `drivers/media/dvb-frontends/si2165.c` DVB, `drivers/of/fdt.c` flatten device tree, and `drivers/pinctrl/samsung/pinctrl-samsung.c` looks unlikely to be reachable.
    *   `drivers/edac/thunderx_edac.c` is ARM64, and likely not relevant for amd64 fuzzing, but I should probably confirm this.
*   **Filesystems:** `fs/nfs/nfsroot.c` and `fs/orangefs/orangefs-debugfs.c`. NFS root setup might be worth a look, and orangefs debugfs sounds interesting, even if less likely to trigger issues.

*   **Core Subsystems:** The most relevant area here is `include/linux/fortify-string.h` and also `net/devlink/dev.c`, `net/sunrpc/addr.c`, `sound/pci/ac97/ac97_codec.c`, and `sound/usb/card.c` and `sound/usb/mixer.c`. This involves `strcat` with fortification. I should be able to target the USB audio drivers.

Okay, let's go back and examine the implications of this commit, and then evaluate the criteria in the guidelines more closely. The original code in `include/linux/fortify-string.h` is replaced by the following logic:

```c
char *strcat(char * const POS p, const char *q)
{
  const size_t p_size = __member_size(p);
  if (p_size == SIZE_MAX)
    return __underlying_strcat(p, q);
  const size_t p_len = __fortify_strlen(p);
  const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q);
  if (p_size <= wanted)
    fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);
}
```

The new definition of `strcat()` uses `__builtin_snprintf()` instead of `strlcat

4/2

2026/09/15 11:08

tool

grepper

Args:

{
  "Expression": "rpc_sockaddr2uaddr"
}

Results:

{
  "Output": "fs/nfs/flexfilelayout/flexfilelayout.c=2770=ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,\n--\nfs/nfs/flexfilelayout/flexfilelayout.c-2807-\nfs/nfs/flexfilelayout/flexfilelayout.c:2808:/* Derived from rpc_sockaddr2uaddr */\nfs/nfs/flexfilelayout/flexfilelayout.c-2809-static void\n--\ninclude/linux/sunrpc/addr.h=17=size_t\t\trpc_pton(struct net *, const char *, const size_t,\ninclude/linux/sunrpc/addr.h-18-\t\t\t struct sockaddr *, const size_t);\ninclude/linux/sunrpc/addr.h:19:char *\t\trpc_sockaddr2uaddr(const struct sockaddr *, gfp_t);\ninclude/linux/sunrpc/addr.h-20-size_t\t\trpc_uaddr2sockaddr(struct net *, const char *, const size_t,\n--\nnet/sunrpc/addr.c=254=EXPORT_SYMBOL_GPL(rpc_pton);\n--\nnet/sunrpc/addr.c-256-/**\nnet/sunrpc/addr.c:257: * rpc_sockaddr2uaddr - Construct a universal address string from @sap.\nnet/sunrpc/addr.c-258- * @sap: socket address\n--\nnet/sunrpc/addr.c-264- */\nnet/sunrpc/addr.c:265:char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)\nnet/sunrpc/addr.c-266-{\n--\nnet/sunrpc/rpcb_clnt.c=482=static int rpcb_register_inet4(struct sunrpc_net *sn,\n--\nnet/sunrpc/rpcb_clnt.c-491-\nnet/sunrpc/rpcb_clnt.c:492:\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);\nnet/sunrpc/rpcb_clnt.c-493-\tif (!map-\u003er_addr)\n--\nnet/sunrpc/rpcb_clnt.c=510=static int rpcb_register_inet6(struct sunrpc_net *sn,\n--\nnet/sunrpc/rpcb_clnt.c-519-\nnet/sunrpc/rpcb_clnt.c:520:\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);\nnet/sunrpc/rpcb_clnt.c-521-\tif (!map-\u003er_addr)\n--\nnet/sunrpc/rpcb_clnt.c=673=void rpcb_getport_async(struct rpc_task *task)\n--\nnet/sunrpc/rpcb_clnt.c-759-\t\tmap-\u003er_netid = xprt-\u003eaddress_strings[RPC_DISPLAY_NETID];\nnet/sunrpc/rpcb_clnt.c:760:\t\tmap-\u003er_addr = rpc_sockaddr2uaddr(sap, rpc_task_gfp_mask());\nnet/sunrpc/rpcb_clnt.c-761-\t\tif (!map-\u003er_addr) {\n"
}

5/2

2026/09/15 11:08

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 24874
							output: 23
							thoughts: 29

Thoughts:

Okay, let's dive into this. Here's how I'd approach that kernel code query:

**Finding the Callers of `__devlink_compat_running_version`**

Alright, so I need to understand where `__devlink_compat_running_version` is being used. First instinct is to jump into the `net/devlink/dev.c` file – that's the logical starting point, considering what's in the text. I'm going to quickly scan that file directly. I'll likely use my editor's search function, likely with the command `grep __devlink_compat_running_version net/devlink/dev.c` in the terminal for a more focused search and also to potentially check other kernel directories and source files. The goal is pinpoint exactly which functions call that specific function. I'm not just looking for direct calls, either. I want to see *how* it's being used – what are the surrounding code blocks, what data is being passed, and what's the overall context. This will provide some important insight into it. Understanding those relationships is the critical part in diagnosing any issue. Once I have the call sites identified, I'll then examine the surrounding code to determine the purpose and impact of the function call in order to understand how the compatibility version is being handled. This is where the real understanding comes from.

6/2

2026/09/15 11:08

tool

grepper

Args:

{
  "Expression": "__devlink_compat_running_version"
}

Results:

{
  "Output": "net/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t     char *buf, size_t len)\n--\nnet/devlink/dev.c=1224=void devlink_compat_running_version(struct devlink *devlink,\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n"
}

7/2

2026/09/15 11:08

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 25474
							output: 22
							thoughts: 18

Thoughts:

Here's my thought process, as if I were analyzing that code:

**Finding the Callers of `devlink_compat_running_version`**

Okay, so I need to understand where this `devlink_compat_running_version` function is being used. This usually means I'm trying to figure out how its return value is being interpreted and what implications that has for the overall system.  I'll start by doing a quick search for all the call sites of this function within the codebase.  That should give me a map of the relevant execution paths and the broader contexts in which it matters. From there, I can begin to assess what logic depends on this particular version number and try to determine where any potential compatibility issues might arise. I'll need to pay close attention to the data types involved in the calls and the conditions being checked; that will be critical for understanding any branching behavior.

8/2

2026/09/15 11:08

tool

grepper

Args:

{
  "Expression": "devlink_compat_running_version"
}

Results:

{
  "Output": "include/net/devlink.h=2121=void devlink_put(struct devlink *devlink);\ninclude/net/devlink.h-2122-\ninclude/net/devlink.h:2123:void devlink_compat_running_version(struct devlink *devlink,\ninclude/net/devlink.h-2124-\t\t\t\t    char *buf, size_t len);\n--\ninclude/net/devlink.h=2146=static inline void\ninclude/net/devlink.h:2147:devlink_compat_running_version(struct devlink *devlink, char *buf, size_t len)\ninclude/net/devlink.h-2148-{\n--\nnet/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t     char *buf, size_t len)\n--\nnet/devlink/dev.c-1223-\nnet/devlink/dev.c:1224:void devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1225-\t\t\t\t    char *buf, size_t len)\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n--\nnet/ethtool/ioctl.c=3646=int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t       state-\u003einfo.fw_version,\n"
}

9/2

2026/09/15 11:08

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 26302
							output: 29
							thoughts: 213

Thoughts:

**My Initial Scan of Potential Code Paths**

Okay, so I've got a bit of a breadcrumb trail here. First, I see that `net/ethtool/ioctl.c` calls `devlink_compat_running_version` which is, of course, accessible through `dev_ethtool` ioctl. Hmm, that could be interesting. I'll need to remember that as I move forward. Now, let's switch gears and delve into the sound subsystem. I need to check `sound/usb/card.c` and `sound/usb/mixer.c`.

Right, in `sound/usb/card.c`, I see `usb_audio_make_longname`. This one is reached through `snd_usb_audio_create`, which in turn is called from `usb_audio_probe`. Pretty standard USB audio setup, but worth noting. Meanwhile, `sound/usb/mixer.c` reveals `append_ctl_name`. This one is a bit more interesting, triggered via `build_connector_control` in the USB audio mixer probe.

Switching gears once more, now I'm looking at `drivers/input/mouse/synaptics_usb.c`. In this case, `synusb_probe` gets called when a USB device with a matching ID is attached. This is another area of interest. Then finally, I want to explore `drivers/comedi/drivers/comedi_bond.c` and specifically `do_dev_config`. This might be a good place to look for other callers or get a sense of how `comedi_bond` works in this case.

10/2

2026/09/15 11:09

tool

grepper

Args:

{
  "Expression": "do_dev_config",
  "PathPrefix": "drivers/comedi"
}

Results:

{
  "Output": "drivers/comedi/drivers/comedi_bond.c=125=static int bonding_dio_insn_config(struct comedi_device *dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-169-\ndrivers/comedi/drivers/comedi_bond.c:170:static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\ndrivers/comedi/drivers/comedi_bond.c-171-{\n--\ndrivers/comedi/drivers/comedi_bond.c=271=static int bonding_attach(struct comedi_device *dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-284-\t */\ndrivers/comedi/drivers/comedi_bond.c:285:\tret = do_dev_config(dev, it);\ndrivers/comedi/drivers/comedi_bond.c-286-\tif (ret)\n"
}

11/2

2026/09/15 11:09

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 27142
							output: 21
							thoughts: 75

Thoughts:

Here's my summary, as though I were thinking through the problem:

**Analyzing the Comedi and DRM Interactions**

Okay, so `bonding_attach` is a `COMEDI_DEVCONFIG` ioctl callback for Comedi. Right, it's designed to specifically link `comedi_bond` functionality to comedi minors. That's good to remember. This strongly suggests a system-level interaction, potentially involving multiplexing or device aggregation within the Comedi framework.

Now, my attention is drawn to `drivers/gpu/drm/display/drm_dp_mst_topology.c`. I need to figure out how this is connected. Let me check where `build_mst_prop_path` is called within that file. I need to understand the potential dependency, especially if it relates to path or topology construction related to a MST connection. This could reveal the nature of the integration – potentially a shared resource, or some configuration information being passed between these two disparate subsystems. Gotta trace that call.

12/2

2026/09/15 11:09

tool

grepper

Args:

{
  "Expression": "build_mst_prop_path"
}

Results:

{
  "Output": "drivers/gpu/drm/display/drm_dp_mst_topology.c=2192=static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, guid_t *guid)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2214-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2215:static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2216-\t\t\t\tint pnum,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=2278=drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2284-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2285:\tbuild_mst_prop_path(mstb, port-\u003eport_num, proppath, sizeof(proppath));\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2286-\tport-\u003econnector = mgr-\u003ecbs-\u003eadd_connector(mgr, port, proppath);\n"
}

13/2

2026/09/15 11:09

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 27792
							output: 38
							thoughts: 35

Thoughts:

Okay, here's my take on those thoughts, framed as an expert's internal monologue:

**Diving into the `fortify-string.h` Rabbit Hole**

Alright, so the conversation's veering towards `include/linux/fortify-string.h`. Naturally, my mind immediately jumps to a deeper dive. Let's see, what specifically is being discussed? It's time to thoroughly examine this header file. We're talking about fortification, so likely memory safety and potential buffer overflows... I need to consider how this interacts with the kernel's overall security posture. Is this about compile-time checks, run-time mitigation, or a combination of both? Are we dealing with string manipulation functions and their safer alternatives? The details here can get quite intricate, given the kernel's needs for performance and stability. I need to understand the exact implementation details of the macros and functions defined within. A quick scan won't do; this warrants a focused, analytical inspection to understand its role in preventing common vulnerabilities.

14/2

2026/09/15 11:09

tool

read-file

Args:

{
  "File": "include/linux/fortify-string.h",
  "FirstLine": 355,
  "LineCount": 35
}

Results:

{
  "Contents": " 355:\t * destination buffer size is known to the compiler. Prefer\n 356:\t * building the string with formatting, via scnprintf() or similar.\n 357:\t * At the very least, use strncat().\n 358:\t *\n 359:\t * Returns @p.\n 360:\t *\n 361:\t */\n 362:\t__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)\n 363:\tchar *strcat(char * const POS p, const char *q)\n 364:\t{\n 365:\t\tconst size_t p_size = __member_size(p);\n 366:\t\n 367:\t\tif (p_size == SIZE_MAX)\n 368:\t\t\treturn __underlying_strcat(p, q);\n 369:\t\n 370:\t\tconst size_t p_len = __fortify_strlen(p);\n 371:\t\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n 372:\t\n 373:\t\tif (p_size \u003c= wanted)\n 374:\t\t\tfortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);\n 375:\t\treturn p;\n 376:\t}\n 377:\t\n 378:\t/**\n 379:\t * strncat - Append a string to an existing string\n 380:\t *\n 381:\t * @p: pointer to NUL-terminated string to append to\n 382:\t * @q: pointer to source string to append from\n 383:\t * @count: Maximum bytes to read from @q\n 384:\t *\n 385:\t * Appends at most @count bytes from @q (stopping at the first\n 386:\t * NUL byte) after the NUL-terminated string at @p. @p will be\n 387:\t * NUL-terminated.\n 388:\t *\n 389:\t * Do not use this function. While FORTIFY_SOURCE tries to avoid\n"
}

15/2

2026/09/15 11:09

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 28662
							output: 20
							thoughts: 941

Thoughts:

**Analyzing Potential Integer Overflow and String Handling Vulnerabilities**

Okay, so I'm looking at this fortified `strcat` implementation in `include/linux/fortify-string.h`, and it's making me think. The original version, using `strlcat`, was fine, but this new one... I'm immediately noticing some potential issues. Specifically, this line:

```c
const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q);
```

My initial thought is that if `p_size <= p_len`, the call to `__builtin_snprintf` could cause some problems. For one, if `p` wasn't properly null-terminated, or if some obscure scenario led to `p_len` being larger than `p_size`, we could have an integer underflow in `p_size - p_len`. Even if that check prevents overflow, then what happens if the check fails and `p_size == p_len`? This results in `p_size - p_len` being 0, which would pass 0 to `snprintf`. And the function returns `strlen(q)`. Meaning `wanted = p_len + strlen(q) >= p_size`, and the panic will be triggered as it should. It seems safe, but I'll need to double check the math. Of course, the whole point of this file is to *fortify* the string functions, so I'd expect it to be careful, but I still have to be diligent. It's a fundamental function, so any flaw here could be catastrophic.

I'm now also looking at a related function, `sound/usb/card.c` specifically, the `usb_audio_make_longname()` function, as it uses string concatenation. I see this section:

```c
size = seq_buf_get_buf(&sb, &buf);
int path_len = usb_make_path(dev, buf, size);
seq_buf_commit(&sb, path_len);
```

My concern is what does `usb_make_path` actually return? The code seems to assume a positive return value, but it's important to understand the full range of possible values here and how it's being used. I will need to check its definition to ensure that it aligns with the logic in `seq_buf_commit`.

16/2

2026/09/15 11:09

tool

grepper

Args:

{
  "Expression": "int usb_make_path"
}

Results:

{
  "Output": "include/linux/usb.h=954=int usb_hub_release_port(struct usb_device *hdev, unsigned port1,\n--\ninclude/linux/usb.h-981- */\ninclude/linux/usb.h:982:static inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)\ninclude/linux/usb.h-983-{\n"
}

17/2

2026/09/15 11:09

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 30266
							output: 35
							thoughts: 20

Thoughts:

Here's a summary of my thought process, as requested:

**Diving into USB Core - Specifically, `usb.h`**

Okay, time to get my hands dirty. I need to understand something specific about the USB subsystem, and my initial instinct is to go right to the header file. I'm thinking, let's start with `include/linux/usb.h`, that's the canonical definition file for all things USB kernel-side. I'm betting a lot of core structures and maybe some key macros are defined in there. I'm going to jump in around line 982. It's often a good starting point for exploring the low-level details. This area probably contains some fundamental definitions or potentially a section that relates to the specific USB concept I'm interested in. I'll get started there and see where the trail leads.

18/2

2026/09/15 11:09

tool

read-file

Args:

{
  "File": "include/linux/usb.h",
  "FirstLine": 980,
  "LineCount": 15
}

Results:

{
  "Contents": " 980:\t * high speed, and a different one if they are full or low speed.\n 981:\t */\n 982:\tstatic inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)\n 983:\t{\n 984:\t\tint actual;\n 985:\t\tactual = snprintf(buf, size, \"usb-%s-%s\", dev-\u003ebus-\u003ebus_name,\n 986:\t\t\t\t  dev-\u003edevpath);\n 987:\t\treturn (actual \u003e= (int)size) ? -1 : actual;\n 988:\t}\n 989:\t\n 990:\t/*-------------------------------------------------------------------------*/\n 991:\t\n 992:\t#define USB_DEVICE_ID_MATCH_DEVICE \\\n 993:\t\t\t(USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT)\n 994:\t#define USB_DEVICE_ID_MATCH_DEV_RANGE \\\n"
}

19/2

2026/09/15 11:09

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 30768
							output: 37
							thoughts: 1305

Thoughts:

**Analyzing String Handling and Buffer Management**

Okay, let's break this down. First, I was looking at `drivers/input/mouse/synaptics_usb.c` and immediately noticed the change from using `usb_make_path` and `strlcat` to `snprintf`.  I'm familiar with this pattern – it looks like they're moving towards more robust and potentially safer string manipulation, specifically to avoid buffer overflows. The use of a temporary `path` variable is also a common and good practice. I'm noting this is a shift in how the physical path is constructed, and likely related to a broader code cleanup.

Next, I jumped to `synusb_probe`. The changes here are more substantial. I see the introduction of `seq_buf_init` and `seq_buf_puts` instead of direct `strscpy` and `strlcat` calls when building the device name. This is a crucial improvement and a good use case for these helper functions for safe string building.  The check for existing manufacturer/product strings also seems cleaner now, using `seq_buf_used` effectively.  I particularly appreciate the use of `seq_buf_printf` for the "USB Synaptics Device" fallback, keeping it concise and efficient.  It looks like a refactoring to modernize string handling with the seq_buf abstraction.

Then, I shifted gears and examined `net/sunrpc/addr.c`. This isn't directly related, but the presence of `snprintf` in `rpc_sockaddr2uaddr` triggered a thought. This reinforces the need for careful buffer management in network code.  I'm using `snprintf` to format the port information.  I had to check the return value, to be sure the port value could be safely converted.

Finally, I dove into `net/devlink/dev.c` and specifically `__devlink_compat_running_version`.  This function utilizes `seq_buf_printf` to construct a version string. My mind immediately went to the null termination of the buffer.  I'm familiar with these issues. The code calls `seq_buf_init` and sets `s.len` with `strnlen`.  That tells me that `seq_buf_init` doesn't implicitly null-terminate, unlike some other string functions. The code then iterates through nested attributes and uses `seq_buf_printf`.  I needed to confirm whether `seq_buf_str(&s)` is called at the end, or whether there is an explicit null termination after the `for` loop. If not, I'm left thinking that the buffer could be not null-terminated, which could lead to subtle bugs or security issues.  I'll need to read the surrounding code to determine if the buffer is properly null-terminated later. Let's see if I have it right! I'm going to look at lines 1180 to 1240 of `net/devlink/dev.c`!

20/2

2026/09/15 11:10

tool

read-file

Args:

{
  "File": "net/devlink/dev.c",
  "FirstLine": 1188,
  "LineCount": 55
}

Results:

{
  "Contents": "1188:\t\n1189:\tstatic void __devlink_compat_running_version(struct devlink *devlink,\n1190:\t\t\t\t\t\t     char *buf, size_t len)\n1191:\t{\n1192:\t\tstruct devlink_info_req req = {};\n1193:\t\tconst struct nlattr *nlattr;\n1194:\t\tstruct seq_buf s;\n1195:\t\tstruct sk_buff *msg;\n1196:\t\tint rem, err;\n1197:\t\n1198:\t\tmsg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);\n1199:\t\tif (!msg)\n1200:\t\t\treturn;\n1201:\t\n1202:\t\treq.msg = msg;\n1203:\t\terr = devlink-\u003eops-\u003einfo_get(devlink, \u0026req, NULL);\n1204:\t\tif (err)\n1205:\t\t\tgoto free_msg;\n1206:\t\n1207:\t\tseq_buf_init(\u0026s, buf, len);\n1208:\t\ts.len = strnlen(buf, len);\n1209:\t\n1210:\t\tnla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,\n1211:\t\t\t\t       (void *)msg-\u003edata, msg-\u003elen, rem) {\n1212:\t\t\tconst struct nlattr *kv;\n1213:\t\t\tint rem_kv;\n1214:\t\n1215:\t\t\tnla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,\n1216:\t\t\t\t\t\t nlattr, rem_kv) {\n1217:\t\t\t\tseq_buf_printf(\u0026s, \"%s \", (const char *)nla_data(kv));\n1218:\t\t\t}\n1219:\t\t}\n1220:\tfree_msg:\n1221:\t\tnlmsg_consume(msg);\n1222:\t}\n1223:\t\n1224:\tvoid devlink_compat_running_version(struct devlink *devlink,\n1225:\t\t\t\t\t    char *buf, size_t len)\n1226:\t{\n1227:\t\tif (!devlink-\u003eops-\u003einfo_get)\n1228:\t\t\treturn;\n1229:\t\n1230:\t\tdevl_lock(devlink);\n1231:\t\tif (devl_is_registered(devlink))\n1232:\t\t\t__devlink_compat_running_version(devlink, buf, len);\n1233:\t\tdevl_unlock(devlink);\n1234:\t}\n1235:\t\n1236:\tint devlink_compat_flash_update(struct devlink *devlink, const char *file_name)\n1237:\t{\n1238:\t\tstruct devlink_flash_update_params params = {};\n1239:\t\tint ret;\n1240:\t\n1241:\t\tdevl_lock(devlink);\n1242:\t\tif (!devl_is_registered(devlink)) {\n"
}

21/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 33568
							output: 19
							thoughts: 234

Thoughts:

**Examining `__devlink_compat_running_version`**

Okay, let's dive into this `__devlink_compat_running_version` function. I see the code, and I'm immediately drawn to the way it handles the output using `seq_buf`.  It looks like it's iterating through some Netlink attributes to pull out running version information.  Specifically, it seems to initialize a `seq_buf` and then processes nested attributes within `DEVLINK_ATTR_INFO_VERSION_RUNNING` using `nla_for_each_nested_type`.  For each version value found within `DEVLINK_ATTR_INFO_VERSION_VALUE`, it's printing it to the `seq_buf` with a space using `seq_buf_printf`.

But a key question immediately springs to mind: What exactly does `seq_buf_printf` do under the hood? Does it guarantee null-termination if the buffer hits its capacity? Or is there potential for issues with string truncation or unexpected behavior? I need to understand the behavior of `seq_buf` to ensure this code is robust. Time to crack open `include/linux/seq_buf.h` to refresh my understanding of how this structure works. I need to make sure I'm not overlooking any potential buffer overflow issues here.

22/2

2026/09/15 11:10

tool

grepper

Args:

{
  "Expression": "seq_buf_str"
}

Results:

{
  "Output": "block/partitions/core.c=119=static struct parsed_partitions *check_partition(struct gendisk *hd)\n--\nblock/partitions/core.c-154-\tif (res \u003e 0) {\nblock/partitions/core.c:155:\t\tprintk(KERN_INFO \"%s\", seq_buf_str(\u0026state-\u003epp_buf));\nblock/partitions/core.c-156-\n--\nblock/partitions/core.c-169-\t\t\t     \" unable to read partition table\\n\");\nblock/partitions/core.c:170:\t\tprintk(KERN_INFO \"%s\", seq_buf_str(\u0026state-\u003epp_buf));\nblock/partitions/core.c-171-\t}\n--\ndrivers/android/tests/binder_alloc_kunit.c=299=static void permute_frees(struct kunit *test, struct binder_alloc *alloc,\n--\ndrivers/android/tests/binder_alloc_kunit.c-319-\t\t\t\t  tc-\u003efront_pages ? \"front\" : \"back \",\ndrivers/android/tests/binder_alloc_kunit.c:320:\t\t\t\t  seq_buf_str(\u0026tc-\u003ealignments_sb),\ndrivers/android/tests/binder_alloc_kunit.c:321:\t\t\t\t  seq_buf_str(\u0026freeseq_sb));\ndrivers/android/tests/binder_alloc_kunit.c-322-\t\t}\n--\ndrivers/comedi/drivers/comedi_bond.c=170=static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\n--\ndrivers/comedi/drivers/comedi_bond.c-265-\ndrivers/comedi/drivers/comedi_bond.c:266:\tseq_buf_str(\u0026s);\ndrivers/comedi/drivers/comedi_bond.c-267-\n--\ndrivers/edac/thunderx_edac.c=1102=static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)\n--\ndrivers/edac/thunderx_edac.c-1153-\t\tif (ctx-\u003ereg_com_int \u0026 OCX_COM_INT_CE)\ndrivers/edac/thunderx_edac.c:1154:\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1155-\n--\ndrivers/edac/thunderx_edac.c=1187=static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id)\n--\ndrivers/edac/thunderx_edac.c-1225-\t\tif (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_UE)\ndrivers/edac/thunderx_edac.c:1226:\t\t\tedac_device_handle_ue(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1227-\t\telse if (ctx-\u003ereg_com_link_int \u0026 OCX_COM_LINK_INT_CE)\ndrivers/edac/thunderx_edac.c:1228:\t\t\tedac_device_handle_ce(ocx-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1229-\n--\ndrivers/edac/thunderx_edac.c=1844=static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)\n--\ndrivers/edac/thunderx_edac.c-1909-\t\tif (ctx-\u003ereg_int \u0026 mask_ue)\ndrivers/edac/thunderx_edac.c:1910:\t\t\tedac_device_handle_ue(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1911-\t\telse if (ctx-\u003ereg_int \u0026 mask_ce)\ndrivers/edac/thunderx_edac.c:1912:\t\t\tedac_device_handle_ce(l2c-\u003eedac_dev, 0, 0, seq_buf_str(\u0026s));\ndrivers/edac/thunderx_edac.c-1913-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=2215=static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2233-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:2234:\tseq_buf_str(\u0026s);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-2235-}\n--\ndrivers/gpu/drm/drm_edid.c=2814=void drm_edid_print_product_id(struct drm_printer *p,\n--\ndrivers/gpu/drm/drm_edid.c-2825-\t\t   vend, le16_to_cpu(id-\u003eproduct_code),\ndrivers/gpu/drm/drm_edid.c:2826:\t\t   le32_to_cpu(id-\u003eserial_number), seq_buf_str(\u0026date));\ndrivers/gpu/drm/drm_edid.c-2827-\n--\ndrivers/gpu/drm/i915/display/intel_ddi.c=5196=static const char *intel_ddi_encoder_name(struct intel_display *display,\n--\ndrivers/gpu/drm/i915/display/intel_ddi.c-5225-\ndrivers/gpu/drm/i915/display/intel_ddi.c:5226:\treturn seq_buf_str(s);\ndrivers/gpu/drm/i915/display/intel_ddi.c-5227-}\n--\ndrivers/gpu/drm/i915/display/intel_dp.c=1504=static void intel_dp_print_rates(struct intel_dp *intel_dp)\n--\ndrivers/gpu/drm/i915/display/intel_dp.c-1512-\tseq_buf_print_array(\u0026s, intel_dp-\u003esource_rates, intel_dp-\u003enum_source_rates);\ndrivers/gpu/drm/i915/display/intel_dp.c:1513:\tdrm_dbg_kms(display-\u003edrm, \"source rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp.c-1514-\n--\ndrivers/gpu/drm/i915/display/intel_dp.c-1516-\tseq_buf_print_array(\u0026s, intel_dp-\u003esink_rates, intel_dp-\u003enum_sink_rates);\ndrivers/gpu/drm/i915/display/intel_dp.c:1517:\tdrm_dbg_kms(display-\u003edrm, \"sink rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp.c-1518-\n--\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c=269=void intel_dp_link_caps_print_common_rates(struct intel_dp_link_caps *link_caps)\n--\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c-277-\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c:278:\tdrm_dbg_kms(display-\u003edrm, \"common rates: %s\\n\", seq_buf_str(\u0026s));\ndrivers/gpu/drm/i915/display/intel_dp_link_caps.c-279-}\n--\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c=63=static void log_underrun_dbg1(struct intel_display *display, enum pipe pipe,\n--\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c-79-\tdrm_err(display-\u003edrm, \"Pipe %c FIFO underrun info: %s on planes: %s\\n\",\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c:80:\t\tpipe_name(pipe), info, seq_buf_str(\u0026planes_desc));\ndrivers/gpu/drm/i915/display/intel_fifo_underrun.c-81-\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=368=static ssize_t sched_group_engines_read(struct file *file, char __user *buf,\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-396-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:397:\ts_str = seq_buf_str(\u0026s);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-398-\treturn simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));\n--\ndrivers/input/mouse/synaptics_usb.c=273=static int synusb_probe(struct usb_interface *intf,\n--\ndrivers/input/mouse/synaptics_usb.c-358-\ndrivers/input/mouse/synaptics_usb.c:359:\tseq_buf_str(\u0026s);\ndrivers/input/mouse/synaptics_usb.c-360-\n--\ndrivers/net/wireless/ath/wil6210/wmi.c=3164=static void resume_triggers2string(u32 triggers, char *string, int str_size)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3188-\ndrivers/net/wireless/ath/wil6210/wmi.c:3189:\tseq_buf_str(\u0026s);\ndrivers/net/wireless/ath/wil6210/wmi.c-3190-}\n--\ndrivers/usb/dwc2/hcd_queue.c=376=static void pmap_print(unsigned long *map, int bits_per_period,\n--\ndrivers/usb/dwc2/hcd_queue.c-420-\t\tif (printed)\ndrivers/usb/dwc2/hcd_queue.c:421:\t\t\tprint_fn(seq_buf_str(\u0026buf), print_data);\ndrivers/usb/dwc2/hcd_queue.c-422-\t}\n--\ninclude/linux/seq_buf.h=77=static inline unsigned int seq_buf_used(struct seq_buf *s)\n--\ninclude/linux/seq_buf.h-82-/**\ninclude/linux/seq_buf.h:83: * seq_buf_str - get NUL-terminated C string from seq_buf\ninclude/linux/seq_buf.h-84- * @s: the seq_buf handle\n--\ninclude/linux/seq_buf.h-97- */\ninclude/linux/seq_buf.h:98:static inline const char *seq_buf_str(struct seq_buf *s)\ninclude/linux/seq_buf.h-99-{\n--\nkernel/bpf/diagnostics.c=336=static void diag_fmt_restore(struct bpf_verifier_env *env, struct diag_fmt_mark mark)\n--\nkernel/bpf/diagnostics.c-353-\t\tmark.chunk-\u003eseq.len = mark.len;\nkernel/bpf/diagnostics.c:354:\t\tseq_buf_str(\u0026mark.chunk-\u003eseq);\nkernel/bpf/diagnostics.c-355-\t}\n--\nkernel/bpf/diagnostics.c=608=static void format_disasm_line(struct bpf_verifier_env *env, int insn_idx,\n--\nkernel/bpf/diagnostics.c-633-\tprint_bpf_insn(\u0026cbs, insn, env-\u003eallow_ptr_leaks);\nkernel/bpf/diagnostics.c:634:\tseq_buf_str(\u0026ctx.seq);\nkernel/bpf/diagnostics.c-635-\tctx.seq.len = strnlen(line-\u003etext, sizeof(line-\u003etext));\n--\nkernel/bpf/diagnostics.c-637-\t\tseq_buf_pop(\u0026ctx.seq);\nkernel/bpf/diagnostics.c:638:\tseq_buf_str(\u0026ctx.seq);\nkernel/bpf/diagnostics.c-639-\n--\nkernel/panic.c=901=static const char *_print_tainted(bool verbose)\n--\nkernel/panic.c-910-\nkernel/panic.c:911:\treturn seq_buf_str(\u0026s);\nkernel/panic.c-912-}\n--\nkernel/rcu/refscale.c=1313=static u64 process_durations(int n)\n--\nkernel/rcu/refscale.c-1335-\t\tif (seq_buf_used(\u0026s) \u003e= 800) {\nkernel/rcu/refscale.c:1336:\t\t\tpr_alert(\"%s\", seq_buf_str(\u0026s));\nkernel/rcu/refscale.c-1337-\t\t\tseq_buf_clear(\u0026s);\n--\nkernel/rcu/refscale.c-1343-\t}\nkernel/rcu/refscale.c:1344:\tpr_alert(\"%s\\n\", seq_buf_str(\u0026s));\nkernel/rcu/refscale.c-1345-\n--\nkernel/sched/core.c=8135=const char *preempt_model_str(void)\n--\nkernel/sched/core.c-8157-\t\t\t\t       brace ? \"}\" : \"\");\nkernel/sched/core.c:8158:\t\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8159-\t\t}\n--\nkernel/sched/core.c-8163-\t\t\t\t       brace ? \"}\" : \"\");\nkernel/sched/core.c:8164:\t\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8165-\t\t}\nkernel/sched/core.c-8166-\nkernel/sched/core.c:8167:\t\treturn seq_buf_str(\u0026s);\nkernel/sched/core.c-8168-\t}\n--\nkernel/trace/trace_events.c=4882=static __init int event_trace_enable(void)\n--\nkernel/trace/trace_events.c-4908-\nkernel/trace/trace_events.c:4909:\tseq_buf_str(\u0026bootup_event_seq);\nkernel/trace/trace_events.c-4910-\tearly_enable_events(tr, bootup_event_buf, false);\n--\nkernel/trace/trace_events.c=4930=static __init int event_trace_enable_again(void)\n--\nkernel/trace/trace_events.c-4937-\nkernel/trace/trace_events.c:4938:\tseq_buf_str(\u0026bootup_event_seq);\nkernel/trace/trace_events.c-4939-\tearly_enable_events(tr, bootup_event_buf, true);\n--\nkernel/trace/trace_events_hist.c=2977=find_synthetic_field_var(struct hist_trigger_data *target_hist_data,\n--\nkernel/trace/trace_events_hist.c-2991-\t/* Terminate synthetic_name with a NUL. */\nkernel/trace/trace_events_hist.c:2992:\tseq_buf_str(\u0026s);\nkernel/trace/trace_events_hist.c-2993-\n--\nkernel/trace/trace_events_hist.c=3032=create_field_var_hist(struct hist_trigger_data *target_hist_data,\n--\nkernel/trace/trace_events_hist.c-3109-\t/* Terminate cmd with a NUL. */\nkernel/trace/trace_events_hist.c:3110:\tseq_buf_str(\u0026s);\nkernel/trace/trace_events_hist.c-3111-\n--\nlib/codetag.c=156=static void *get_symbol(struct module *mod, const char *prefix, const char *name)\n--\nlib/codetag.c-165-\nlib/codetag.c:166:\tbuf = seq_buf_str(\u0026sb);\nlib/codetag.c-167-\tpreempt_disable();\n--\nlib/seq_buf.c=115=void seq_buf_do_printk(struct seq_buf *s, const char *lvl)\n--\nlib/seq_buf.c-121-\nlib/seq_buf.c:122:\tstart = seq_buf_str(s);\nlib/seq_buf.c-123-\twhile ((lf = strchr(start, '\\n'))) {\n--\nlib/tests/seq_buf_kunit.c=11=static void seq_buf_init_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-22-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 0);\nlib/tests/seq_buf_kunit.c:23:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-24-}\n--\nlib/tests/seq_buf_kunit.c=26=static void seq_buf_declare_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-34-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 0);\nlib/tests/seq_buf_kunit.c:35:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-36-}\n--\nlib/tests/seq_buf_kunit.c=38=static void seq_buf_clear_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-44-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:45:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-46-\n--\nlib/tests/seq_buf_kunit.c-50-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:51:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-52-}\n--\nlib/tests/seq_buf_kunit.c=54=static void seq_buf_puts_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-60-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:61:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-62-\n--\nlib/tests/seq_buf_kunit.c-65-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:66:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-67-}\n--\nlib/tests/seq_buf_kunit.c=69=static void seq_buf_puts_overflow_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-79-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 10);\nlib/tests/seq_buf_kunit.c:80:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"123456789\");\nlib/tests/seq_buf_kunit.c-81-\n--\nlib/tests/seq_buf_kunit.c-84-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:85:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-86-}\n--\nlib/tests/seq_buf_kunit.c=88=static void seq_buf_putc_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-97-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:98:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-99-\n--\nlib/tests/seq_buf_kunit.c-102-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:103:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-104-\n--\nlib/tests/seq_buf_kunit.c-107-\tKUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:108:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"abc\");\nlib/tests/seq_buf_kunit.c-109-\n--\nlib/tests/seq_buf_kunit.c-112-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:113:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-114-}\n--\nlib/tests/seq_buf_kunit.c=116=static void seq_buf_printf_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-122-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:123:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-124-\n--\nlib/tests/seq_buf_kunit.c-127-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:128:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world 123\");\nlib/tests/seq_buf_kunit.c-129-}\n--\nlib/tests/seq_buf_kunit.c=131=static void seq_buf_printf_overflow_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-137-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 10);\nlib/tests/seq_buf_kunit.c:138:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"1234567890\");\nlib/tests/seq_buf_kunit.c-139-\n--\nlib/tests/seq_buf_kunit.c-142-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 16);\nlib/tests/seq_buf_kunit.c:143:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"1234567890abcde\");\nlib/tests/seq_buf_kunit.c-144-\n--\nlib/tests/seq_buf_kunit.c-147-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:148:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"\");\nlib/tests/seq_buf_kunit.c-149-}\n--\nlib/tests/seq_buf_kunit.c=151=static void seq_buf_get_buf_commit_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-165-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:166:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello\");\nlib/tests/seq_buf_kunit.c-167-\n--\nlib/tests/seq_buf_kunit.c-176-\tKUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(\u0026s));\nlib/tests/seq_buf_kunit.c:177:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), \"hello world\");\nlib/tests/seq_buf_kunit.c-178-\n--\nlib/tests/seq_buf_kunit.c=187=static void seq_buf_putmem_hex_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-199-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), strlen(expected));\nlib/tests/seq_buf_kunit.c:200:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), expected);\nlib/tests/seq_buf_kunit.c-201-}\n--\nlib/tests/seq_buf_kunit.c=203=static void seq_buf_putmem_hex_overflow_test(struct kunit *test)\n--\nlib/tests/seq_buf_kunit.c-215-\tKUNIT_EXPECT_EQ(test, seq_buf_used(\u0026s), 20);\nlib/tests/seq_buf_kunit.c:216:\tKUNIT_EXPECT_STREQ(test, seq_buf_str(\u0026s), expected);\nlib/tests/seq_buf_kunit.c-217-}\n--\nsound/soc/codecs/cs35l56-shared-test.c=725=static void cs35l56_shared_test_gpio_param_desc(const struct cs35l56_shared_test_param *param,\n--\nsound/soc/codecs/cs35l56-shared-test.c-746-\tsnprintf(desc, KUNIT_PARAM_DESC_SIZE, \"gpios:{%s} pulls:{%s} status:%#lx spkid:%d\",\nsound/soc/codecs/cs35l56-shared-test.c:747:\t\t seq_buf_str(\u0026gpios), seq_buf_str(\u0026pulls), param-\u003egpio_status, param-\u003espkid);\nsound/soc/codecs/cs35l56-shared-test.c-748-}\n--\nsound/soc/codecs/cs35l56-test.c=590=static void cs35l56_test_gpio_param_desc(const struct cs35l56_test_param *param, char *desc)\n--\nsound/soc/codecs/cs35l56-test.c-610-\tsnprintf(desc, KUNIT_PARAM_DESC_SIZE, \"gpios:{%s} pulls:{%s}\",\nsound/soc/codecs/cs35l56-test.c:611:\t\t seq_buf_str(\u0026gpios), seq_buf_str(\u0026pulls));\nsound/soc/codecs/cs35l56-test.c-612-}\n--\nsound/usb/card.c=648=static void usb_audio_make_longname(struct usb_device *dev,\n--\nsound/usb/card.c-683-\nsound/usb/card.c:684:\t\tseq_buf_str(\u0026sb);\nsound/usb/card.c-685-\t\ttrimmed = strim(card-\u003elongname);\n--\nsound/usb/card.c-726-\nsound/usb/card.c:727:\tseq_buf_str(\u0026sb);\nsound/usb/card.c-728-}\n"
}

23/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 41497
							output: 36
							thoughts: 31

Thoughts:

Here's my attempt at summarizing the thought process, as if I were a Linux kernel expert:

**Understanding the `seq_buf` Implementation**

Okay, time to dive into the nitty-gritty. I'm going to take a look at the `seq_buf` implementation, specifically the header file `include/linux/seq_buf.h`. I've been meaning to refresh my memory on the details of how this works, and now's as good a time as any. I want to see exactly how the `seq_buf` structure itself is defined, how the buffer allocation and management functions are structured, and what the core principles are behind its design. I'm especially interested in the mechanics of its growth strategy. I need to refresh my mind on the locking strategy and understand how it handles synchronization within a concurrent context. I’m thinking about this because I'm troubleshooting some kernel performance issues, and knowing the low-level details of things like `seq_buf` is crucial for debugging and optimization. It's time to refresh the core concepts in my mind and make sure I know how this utility is designed.

24/2

2026/09/15 11:10

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 80,
  "LineCount": 40
}

Results:

{
  "Contents": "  80:\t}\n  81:\t\n  82:\t/**\n  83:\t * seq_buf_str - get NUL-terminated C string from seq_buf\n  84:\t * @s: the seq_buf handle\n  85:\t *\n  86:\t * This makes sure that the buffer in @s is NUL-terminated and\n  87:\t * safe to read as a string.\n  88:\t *\n  89:\t * Note, if this is called when the buffer has overflowed, then\n  90:\t * the last byte of the buffer is zeroed, and the len will still\n  91:\t * point passed it.\n  92:\t *\n  93:\t * After this function is called, s-\u003ebuffer is safe to use\n  94:\t * in string operations.\n  95:\t *\n  96:\t * Returns: @s-\u003ebuf after making sure it is terminated.\n  97:\t */\n  98:\tstatic inline const char *seq_buf_str(struct seq_buf *s)\n  99:\t{\n 100:\t\tif (WARN_ON(s-\u003esize == 0))\n 101:\t\t\treturn \"\";\n 102:\t\n 103:\t\tif (seq_buf_buffer_left(s))\n 104:\t\t\ts-\u003ebuffer[s-\u003elen] = 0;\n 105:\t\telse\n 106:\t\t\ts-\u003ebuffer[s-\u003esize - 1] = 0;\n 107:\t\n 108:\t\treturn s-\u003ebuffer;\n 109:\t}\n 110:\t\n 111:\t/**\n 112:\t * seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t *\n 116:\t * Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t */\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)\n"
}

25/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 42370
							output: 34
							thoughts: 408

Thoughts:

**Analyzing `net/devlink/dev.c`'s `__devlink_compat_running_version`**

Okay, let's dive back into `net/devlink/dev.c` and specifically this function, `__devlink_compat_running_version`.  I see it's handling the retrieval and formatting of the running version information.  It's using `netlink` which is pretty standard for these sorts of device interactions. It looks like it's constructing a netlink message (`req`) and then calling the device's specific `info_get` function.  It then uses a `seq_buf` to build the string representation of the version.

Hold on... something feels off.  I'm looking at how it processes the attributes within the netlink message, and specifically, the nested attributes under `DEVLINK_ATTR_INFO_VERSION_RUNNING` and then `DEVLINK_ATTR_INFO_VERSION_VALUE`. It loops through and prints the value of each. However, I don't see any explicit null-termination of the `seq_buf`.  It looks like it's just building the string directly into a buffer.

Ah ha! I'm pretty sure `seq_buf_printf` itself does *not* null-terminate. That could be a problem!  I need to verify whether the buffer is null-terminated or not. I'd better confirm this, so let's jump over to `lib/seq_buf.c` and take a look at the definition of `seq_buf_vprintf` because that's what `seq_buf_printf` calls.

26/2

2026/09/15 11:10

tool

read-file

Args:

{
  "File": "lib/seq_buf.c",
  "FirstLine": 55,
  "LineCount": 50
}

Results:

{
  "Contents": "  55:\t}\n  56:\t\n  57:\t/**\n  58:\t * seq_buf_vprintf - sequence printing of information.\n  59:\t * @s: seq_buf descriptor\n  60:\t * @fmt: printf format string\n  61:\t * @args: va_list of arguments from a printf() type function\n  62:\t *\n  63:\t * Writes a vnprintf() format into the sequence buffer.\n  64:\t *\n  65:\t * Returns: zero on success, -1 on overflow.\n  66:\t */\n  67:\tint seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)\n  68:\t{\n  69:\t\tint len;\n  70:\t\n  71:\t\tWARN_ON(s-\u003esize == 0);\n  72:\t\n  73:\t\tif (s-\u003elen \u003c s-\u003esize) {\n  74:\t\t\tlen = vsnprintf(s-\u003ebuffer + s-\u003elen, s-\u003esize - s-\u003elen, fmt, args);\n  75:\t\t\tif (s-\u003elen + len \u003c s-\u003esize) {\n  76:\t\t\t\ts-\u003elen += len;\n  77:\t\t\t\treturn 0;\n  78:\t\t\t}\n  79:\t\t}\n  80:\t\tseq_buf_set_overflow(s);\n  81:\t\treturn -1;\n  82:\t}\n  83:\t\n  84:\t/**\n  85:\t * seq_buf_printf - sequence printing of information\n  86:\t * @s: seq_buf descriptor\n  87:\t * @fmt: printf format string\n  88:\t *\n  89:\t * Writes a printf() format into the sequence buffer.\n  90:\t *\n  91:\t * Returns: zero on success, -1 on overflow.\n  92:\t */\n  93:\tint seq_buf_printf(struct seq_buf *s, const char *fmt, ...)\n  94:\t{\n  95:\t\tva_list ap;\n  96:\t\tint ret;\n  97:\t\n  98:\t\tva_start(ap, fmt);\n  99:\t\tret = seq_buf_vprintf(s, fmt, ap);\n 100:\t\tva_end(ap);\n 101:\t\n 102:\t\treturn ret;\n 103:\t}\n 104:\tEXPORT_SYMBOL_GPL(seq_buf_printf);\n"
}

27/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 43797
							output: 36
							thoughts: 87

Thoughts:

Here's my thought process, as it unfolds:

**Examining Potential Buffer Overflows in `vsnprintf` within a `seq_buf` Context**

Okay, hold on a second! I'm zeroing in on this line: `vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);`.  My brain immediately flags a potential issue, given what I'm seeing with the `seq_buf` structure. Specifically, *if* `s->len + len` (the current buffer length plus the length of the string to be added) becomes greater than or equal to `s->size` (the total buffer capacity), the code calls `seq_buf_set_overflow(s);`.  That's my cue to investigate. What *exactly* does `seq_buf_set_overflow` do? I'm familiar with the concept and architecture, and I think I vaguely remember where the definition might be, but it's time to confirm and refresh the details. Let's dive into the `include/linux/seq_buf.h` header and see what it reveals.

28/2

2026/09/15 11:10

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 55,
  "LineCount": 25
}

Results:

{
  "Contents": "  55:\t\treturn s-\u003elen \u003e s-\u003esize;\n  56:\t}\n  57:\t\n  58:\tstatic inline void\n  59:\tseq_buf_set_overflow(struct seq_buf *s)\n  60:\t{\n  61:\t\ts-\u003elen = s-\u003esize + 1;\n  62:\t}\n  63:\t\n  64:\t/*\n  65:\t * How much buffer is left on the seq_buf?\n  66:\t */\n  67:\tstatic inline unsigned int\n  68:\tseq_buf_buffer_left(struct seq_buf *s)\n  69:\t{\n  70:\t\tif (seq_buf_has_overflowed(s))\n  71:\t\t\treturn 0;\n  72:\t\n  73:\t\treturn s-\u003esize - s-\u003elen;\n  74:\t}\n  75:\t\n  76:\t/* How much buffer was written? */\n  77:\tstatic inline unsigned int seq_buf_used(struct seq_buf *s)\n  78:\t{\n  79:\t\treturn min(s-\u003elen, s-\u003esize);\n"
}

29/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 44467
							output: 35
							thoughts: 646

Thoughts:

**Analyzing the Fuzzing Potential of This Patch**

Okay, so I'm looking at this code and trying to figure out if it's worth the fuzzing effort. First, I was thinking about `vsnprintf` and the null termination behavior when buffer lengths and offsets are in play, but that's a bit of a tangent. The key question is whether this patch introduces any new, reachable code that's ripe for fuzzing.

I'm checking against the established guidelines for fuzzing targets: memory management, synchronization, BPF, scheduler, networking, VFS, syscalls, refactorings, assertions, and drivers accessible via specific virtual buses or protocols.

Right, so this patch is touching `include/linux/fortify-string.h`. Specifically, the fortified `strcat()` implementation. This immediately grabs my attention. Let's see...

```c
char *strcat(char * const POS p, const char *q)
{
	const size_t p_size = __member_size(p);

	if (p_size == SIZE_MAX)
		return __underlying_strcat(p, q);

	const size_t p_len = __fortify_strlen(p);
	const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q);

	if (p_size <= wanted)
		fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);
	return p;
}
```

Okay, so they're changing the fortify string check for `strcat`. Crucially, `strcat` is used all over the kernel. *And* when `CONFIG_FORTIFY_SOURCE` is enabled, all callers that have known size use this fortified version. That's a significant surface area.

Now, hold on... `fortify_panic()` is a runtime assertion! That's a huge flag for fuzzing, because that's a place to trigger intentional failures. And the `p_size <= wanted` check... Let me check the fortify strlen check in `include/linux/fortify-string.h`.

30/2

2026/09/15 11:10

tool

grepper

Args:

{
  "Expression": "__fortify_strlen",
  "PathPrefix": "include/linux/fortify-string.h"
}

Results:

{
  "Output": "include/linux/fortify-string.h=169=__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)\n--\ninclude/linux/fortify-string.h-208-\t__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),\t\\\ninclude/linux/fortify-string.h:209:\t\t__builtin_strlen(p), __fortify_strlen(p))\ninclude/linux/fortify-string.h-210-__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\ninclude/linux/fortify-string.h:211:__kernel_size_t __fortify_strlen(const char * const POS p)\ninclude/linux/fortify-string.h-212-{\n--\ninclude/linux/fortify-string.h=363=char *strcat(char * const POS p, const char *q)\n--\ninclude/linux/fortify-string.h-369-\ninclude/linux/fortify-string.h:370:\tconst size_t p_len = __fortify_strlen(p);\ninclude/linux/fortify-string.h-371-\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n"
}

31/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 45989
							output: 38
							thoughts: 26

Thoughts:

Here's a summary of my thought process, as if I were the one reading and analyzing that code:

**Diving into `fortify-string.h`**

Okay, I'm going to take a look at lines 211-225 in `include/linux/fortify-string.h`. Right, this is where the kernel's string safety mechanisms are defined. I'm expecting to see some macros or functions designed to catch buffer overflows and similar vulnerabilities. I'm hoping to understand how they're implemented, any trade-offs they might make (performance vs. safety), and how they interact with the compiler. I'll be looking for any clever optimizations or potential gotchas that I might have missed in the past. This area is crucial, as any weakness here could be exploited. Let's see what's being done.

32/2

2026/09/15 11:10

tool

read-file

Args:

{
  "File": "include/linux/fortify-string.h",
  "FirstLine": 210,
  "LineCount": 20
}

Results:

{
  "Contents": " 210:\t__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\n 211:\t__kernel_size_t __fortify_strlen(const char * const POS p)\n 212:\t{\n 213:\t\tconst size_t p_size = __member_size(p);\n 214:\t\t__kernel_size_t ret;\n 215:\t\n 216:\t\t/* Give up if we don't know how large p is. */\n 217:\t\tif (p_size == SIZE_MAX)\n 218:\t\t\treturn __underlying_strlen(p);\n 219:\t\tret = strnlen(p, p_size);\n 220:\t\tif (p_size \u003c= ret)\n 221:\t\t\tfortify_panic(FORTIFY_FUNC_strlen, FORTIFY_READ, p_size, ret + 1, ret);\n 222:\t\treturn ret;\n 223:\t}\n 224:\t\n 225:\t/* Defined after fortified strnlen() to reuse it. */\n 226:\textern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(sized_strscpy);\n 227:\t__FORTIFY_INLINE ssize_t sized_strscpy(char * const POS p, const char * const POS q, size_t size)\n 228:\t{\n 229:\t\t/* Use string size rather than possible enclosing struct size. */\n"
}

33/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 46626
							output: 32
							thoughts: 71

Thoughts:

**Investigating Synaptics USB Mouse Driver Reachability**

Okay, so I need to figure out how the `synaptics_usb` driver is handled. My first move is to dive into the source code itself – specifically, the `drivers/input/mouse/synaptics_usb.c` file. Right, let's open that up and get a sense of its structure.

Now, a crucial question pops up: Is this driver even *reachable* in my current configuration? It's not enough that the code exists; it has to be compiled and accessible. So, I need to verify its compilation state. I need to know, is this module built into the kernel, compiled as a module, or disabled entirely? Is it maybe emulated via USB?

My go-to here is the `Kconfig` file. I'm going to search for `CONFIG_MOUSE_SYNAPTICS_USB`. That should tell me the dependency chain, and the condition in which this driver gets enabled, or at least how it's handled during configuration. This should provide me with an explicit path as to how this driver is included, if it is at all.

34/2

2026/09/15 11:10

tool

grepper

Args:

{
  "Expression": "MOUSE_SYNAPTICS_USB",
  "PathPrefix": "drivers/input/mouse"
}

Results:

{
  "Output": "drivers/input/mouse/Kconfig=361=config MOUSE_SYNAPTICS_I2C\n--\ndrivers/input/mouse/Kconfig-378-\ndrivers/input/mouse/Kconfig:379:config MOUSE_SYNAPTICS_USB\ndrivers/input/mouse/Kconfig-380-\ttristate \"Synaptics USB device support\"\n--\ndrivers/input/mouse/Makefile=19=obj-$(CONFIG_MOUSE_SYNAPTICS_I2C)\t+= synaptics_i2c.o\ndrivers/input/mouse/Makefile:20:obj-$(CONFIG_MOUSE_SYNAPTICS_USB)\t+= synaptics_usb.o\ndrivers/input/mouse/Makefile-21-obj-$(CONFIG_MOUSE_VSXXXAA)\t\t+= vsxxxaa.o\n"
}

35/2

2026/09/15 11:10

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 47180
							output: 35
							thoughts: 1124

Thoughts:

**Analyzing Reachability and Focus for Fuzzing**

Okay, so I've got this patch in front of me, and my initial thought is: *can we actually fuzz this effectively?* The goal is to maximize the impact of fuzzing efforts, so I need to assess whether these code changes are *reachable* and *fuzzable*.

First, let's break down the individual components. The `MOUSE_SYNAPTICS_USB` driver, a USB device, is definitely interesting. Reachable through USB emulation, like syzkaller with dummy_hcd or raw-gadget.

Then, there's the audio stuff: `sound/usb/card.c` and `sound/usb/mixer.c`, part of `CONFIG_SND_USB_AUDIO`. This is promising because `snd-usb-audio` is a known fuzzing target, heavily tested with syzkaller via virtual USB emulation. Specifically, I see that `usb_audio_make_longname` in `sound/usb/card.c` has been touched, as well as modifications to `append_ctl_name` and `build_connector_control` in `sound/usb/mixer.c`. This is definitely something I want to investigate.

Next up, the networking: `net/sunrpc/addr.c` with the `rpc_sockaddr2uaddr()` function, part of `CONFIG_SUNRPC`. This is core to SUNRPC, NFS/RPC, and thus reachable through network syscalls, sockets, and NFS. Definitely a good target.

Then, `net/devlink/dev.c` with `__devlink_compat_running_version`, part of devlink/ethtool networking (`CONFIG_NET`). Reachable via ethtool ioctls on devlink devices.

Finally, the `drivers/comedi/drivers/comedi_bond.c`, part of `CONFIG_COMEDI_BOND` and comedi driver. Configurable via ioctls.

So, I am confident that these are all executable code that has been modified.

Now, let's consider the *negative* criteria. We don't want to waste effort on changes that aren't actually executable.

*   No non-kernel code, or docs, or purely decorative logging - Nope, we have actual C code.
*   No structurally unreachable hardware - While some files touch unreachable hardware (like `drivers/edac/thunderx_edac.c`, `drivers/scsi/bfa/bfa_fcs.c`, `drivers/net/ethernet/intel/i40e/i40e.h`), other files are very much reachable via USB, Networking, ioctls, etc, and work in QEMU / syzkaller.
*   No unreachable execution paths (e.g., specific to an uninteresting architecture) - The code is for amd64 and reachable during device probe/attach, netlink/ioctl, RPC operations, and general kernel execution.

Therefore, since all the reachable code is valid and testable, `WorthFuzzing` is definitively TRUE!

Alright, now the key part: *FocusSymbols and EnableConfigs*. We need to be smart about what we focus on. Remember section 4 of the guidelines: **AVOID UBIQUITOUS LIFECYCLE HOT-PATHS**. Don't list general, ubiquitous functions like allocators, deallocators, or synchronization primitives. That'll just dilute the fuzzing.

Wait, is `strcat` in `include/linux/fortify-string.h` a ubiquitous lifecycle function? Yes, it is. The change is in a static inline function in a header!

Let's refer back to Section 4: "HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers)."

So we cannot directly target `strcat` because it has no symbol address in the final image, and if we did target callers that use it ubiquitously, it would dilute the fuzzing effort.

The question then becomes: What are the *non-ubiquitous, specific functions* that implement the logic being added or altered, avoiding the inlined helpers like `strcat`? We need to pinpoint the relevant functions that *call* this inlined code, to improve our coverage and prevent dilution of the fuzzing. We need to go through each changed function in the patch:

1.  `sound/usb/card.c`:

36/2

2026/09/15 11:11

tool

read-file

Args:

{
  "File": "sound/usb/card.c",
  "FirstLine": 645,
  "LineCount": 25
}

Results:

{
  "Contents": " 645:\t\tstrim(card-\u003eshortname);\n 646:\t}\n 647:\t\n 648:\tstatic void usb_audio_make_longname(struct usb_device *dev,\n 649:\t\t\t\t\t    struct snd_usb_audio *chip,\n 650:\t\t\t\t\t    const struct snd_usb_audio_quirk *quirk)\n 651:\t{\n 652:\t\tstruct snd_card *card = chip-\u003ecard;\n 653:\t\tconst struct usb_audio_device_name *preset;\n 654:\t\tconst char *s = NULL;\n 655:\t\tstruct seq_buf sb;\n 656:\t\tchar *buf;\n 657:\t\tsize_t size;\n 658:\t\n 659:\t\tpreset = lookup_device_name(chip-\u003eusb_id);\n 660:\t\n 661:\t\t/* shortcut - if any pre-defined string is given, use it */\n 662:\t\tif (preset \u0026\u0026 preset-\u003eprofile_name)\n 663:\t\t\ts = preset-\u003eprofile_name;\n 664:\t\tif (s \u0026\u0026 *s) {\n 665:\t\t\tstrscpy(card-\u003elongname, s, sizeof(card-\u003elongname));\n 666:\t\t\treturn;\n 667:\t\t}\n 668:\t\n 669:\t\tif (preset \u0026\u0026 preset-\u003evendor_name)\n"
}

37/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 49736
							output: 31
							thoughts: 19

Thoughts:

Here's my take on those thoughts:

**Tracing the Call Path: usb\_audio\_make\_longname**

Okay, so I need to understand the flow here. My immediate thought is, "Where exactly does this `usb_audio_make_longname` function get invoked?" I need to see the calling contexts. A function name by itself doesn't tell me much. It could be a critical part of the audio pipeline or some obscure debugging helper. Understanding the call stack is paramount to grasping its significance. Knowing its callers will tell me a lot about its purpose and how it fits into the broader audio driver architecture. Time to dig in and trace those calls.

38/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "usb_audio_make_longname",
  "PathPrefix": "sound/usb"
}

Results:

{
  "Output": "sound/usb/card.c=616=static void usb_audio_make_shortname(struct usb_device *dev,\n--\nsound/usb/card.c-647-\nsound/usb/card.c:648:static void usb_audio_make_longname(struct usb_device *dev,\nsound/usb/card.c-649-\t\t\t\t    struct snd_usb_audio *chip,\n--\nsound/usb/card.c=758=static int snd_usb_audio_create(struct usb_interface *intf,\n--\nsound/usb/card.c-821-\tusb_audio_make_shortname(dev, chip, quirk);\nsound/usb/card.c:822:\tusb_audio_make_longname(dev, chip, quirk);\nsound/usb/card.c-823-\n"
}

39/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 50145
							output: 30
							thoughts: 68

Thoughts:

**Tracing the `usb_audio_make_longname` Function**

Okay, so I'm diving into this `usb_audio_make_longname` function. Right, it's a static function, nestled away in `sound/usb/card.c`. That's good to know – static means it's only visible within that file. I remember seeing it called by `snd_usb_audio_create`. Now, the key question is, what *calls* `snd_usb_audio_create`? That's where the investigation begins! I'll head back over to `sound/usb/card.c` and start retracing the call stack to see where that function is actually invoked, and under what conditions. Understanding the calling context is crucial to grasping the overall behavior.

40/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "snd_usb_audio_create",
  "PathPrefix": "sound/usb"
}

Results:

{
  "Output": "sound/usb/card.c=730=static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)\n--\nsound/usb/card.c-757- */\nsound/usb/card.c:758:static int snd_usb_audio_create(struct usb_interface *intf,\nsound/usb/card.c-759-\t\t\t\tstruct usb_device *dev, int idx,\n--\nsound/usb/card.c-823-\nsound/usb/card.c:824:\tsnd_usb_audio_create_proc(chip);\nsound/usb/card.c-825-\n--\nsound/usb/card.c=972=static int usb_audio_probe(struct usb_interface *intf,\n--\nsound/usb/card.c-1030-\t\t\t\tif (enable[i]) {\nsound/usb/card.c:1031:\t\t\t\t\terr = snd_usb_audio_create(intf, dev, i, quirk,\nsound/usb/card.c-1032-\t\t\t\t\t\t\t\t   id, \u0026chip);\n--\nsound/usb/proc.c=40=static void proc_audio_usbid_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)\n--\nsound/usb/proc.c-48-\nsound/usb/proc.c:49:void snd_usb_audio_create_proc(struct snd_usb_audio *chip)\nsound/usb/proc.c-50-{\n--\nsound/usb/proc.h-4-\nsound/usb/proc.h:5:void snd_usb_audio_create_proc(struct snd_usb_audio *chip);\nsound/usb/proc.h-6-void snd_usb_proc_pcm_format_add(struct snd_usb_stream *stream);\n"
}

41/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 50876
							output: 36
							thoughts: 103

Thoughts:

**Analyzing USB Audio Probe**

Okay, so `usb_audio_probe` kicks things off, and I know it ultimately calls `snd_usb_audio_create`. That makes sense. Now I want to understand more about the naming and creation process, so let's see what `usb_audio_make_longname` is doing. I need to dig into the details a little deeper.

Right, let's switch gears and go into `sound/usb/mixer.c`. I have a hunch that changes there might be relevant to the device recognition and naming, which is where my investigation is focused. The key is in the mixer controls, of course. Hmm, what functions were changed? Let's refresh my memory of recent updates. Ah, I see: `append_ctl_name` and `build_connector_control`. Those are the prime suspects, dealing directly with control naming and structure.

Time to focus in. Let's look closely at lines 2085 to 2105 in `sound/usb/mixer.c`. That should give me the context I need to understand what's going on with the naming and control structure within the USB audio driver.

42/2

2026/09/15 11:11

tool

read-file

Args:

{
  "File": "sound/usb/mixer.c",
  "FirstLine": 2085,
  "LineCount": 25
}

Results:

{
  "Contents": "2085:\t\tcval-\u003eval_type = USB_MIXER_BOOLEAN;\n2086:\t\tcval-\u003echannels = 1; /* report true if any channel is connected */\n2087:\t\tcval-\u003emin = 0;\n2088:\t\tcval-\u003emax = 1;\n2089:\t\tkctl = snd_ctl_new1(\u0026usb_connector_ctl_ro, cval);\n2090:\t\tif (!kctl) {\n2091:\t\t\tusb_audio_err(mixer-\u003echip, \"cannot malloc kcontrol\\n\");\n2092:\t\t\tusb_mixer_elem_info_free(cval);\n2093:\t\t\treturn;\n2094:\t\t}\n2095:\t\n2096:\t\tif (check_mapped_name(map, kctl-\u003eid.name, sizeof(kctl-\u003eid.name)))\n2097:\t\t\tappend_ctl_name(kctl, \" Jack\");\n2098:\t\telse\n2099:\t\t\tget_connector_control_name(mixer, term, is_input, kctl-\u003eid.name,\n2100:\t\t\t\t\t\t   sizeof(kctl-\u003eid.name));\n2101:\t\tkctl-\u003eprivate_free = snd_usb_mixer_elem_free;\n2102:\t\tsnd_usb_mixer_add_control(\u0026cval-\u003ehead, kctl);\n2103:\t}\n2104:\t\n2105:\tstatic int parse_clock_source_unit(struct mixer_build *state, int unitid,\n2106:\t\t\t\t\t   void *_ftr)\n2107:\t{\n2108:\t\tstruct uac_clock_source_descriptor *hdr = _ftr;\n2109:\t\tstruct usb_mixer_elem_info *cval;\n"
}

43/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 51728
							output: 29
							thoughts: 52

Thoughts:

Okay, let's dive into this. I need to take a look at `drivers/input/mouse/synaptics_usb.c`. Specifically, I'm interested in the `synusb_probe` function. The first thing I always do with a probe function is quickly identify if it's static or non-static. The visibility of the probe function changes its scope, and thus its utility. Let's get that identified first.

44/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "synusb_probe",
  "PathPrefix": "drivers/input/mouse"
}

Results:

{
  "Output": "drivers/input/mouse/synaptics_usb.c=256=static void synusb_close(struct input_dev *dev)\n--\ndrivers/input/mouse/synaptics_usb.c-272-\ndrivers/input/mouse/synaptics_usb.c:273:static int synusb_probe(struct usb_interface *intf,\ndrivers/input/mouse/synaptics_usb.c-274-\t\t\tconst struct usb_device_id *id)\n--\ndrivers/input/mouse/synaptics_usb.c=532=static struct usb_driver synusb_driver = {\ndrivers/input/mouse/synaptics_usb.c-533-\t.name\t\t= \"synaptics_usb\",\ndrivers/input/mouse/synaptics_usb.c:534:\t.probe\t\t= synusb_probe,\ndrivers/input/mouse/synaptics_usb.c-535-\t.disconnect\t= synusb_disconnect,\n"
}

45/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 52154
							output: 41
							thoughts: 191

Thoughts:

**My Initial Thoughts on the Code**

Okay, so I'm looking at this code and immediately I see `synusb_probe`. That's the probe callback for `synaptics_usb`, which is where I want to start. Now, let's see what else might be relevant. Let's move on to `net/sunrpc/addr.c`. Hmm, `rpc_sockaddr2uaddr` is exported, that's interesting. It's a character pointer function taking a socket address structure and a GFP flag. Worth noting, maybe, depending on context. Next, let's jump over to `net/devlink/dev.c`. I spot `__devlink_compat_running_version` and `devlink_compat_running_version`. Specifically a function `devlink_compat_running_version` is here. That's a void function. Finally, there's something in `drivers/comedi/drivers/comedi_bond.c`. I see `do_dev_config`, which is called by `bonding_attach`. Definitely worth a closer look, let's examine `drivers/comedi/drivers/comedi_bond.c` more thoroughly.

46/2

2026/09/15 11:11

tool

read-file

Args:

{
  "File": "drivers/comedi/drivers/comedi_bond.c",
  "FirstLine": 270,
  "LineCount": 30
}

Results:

{
  "Contents": " 270:\t\n 271:\tstatic int bonding_attach(struct comedi_device *dev,\n 272:\t\t\t\t  struct comedi_devconfig *it)\n 273:\t{\n 274:\t\tstruct comedi_bond_private *devpriv;\n 275:\t\tstruct comedi_subdevice *s;\n 276:\t\tint ret;\n 277:\t\n 278:\t\tdevpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));\n 279:\t\tif (!devpriv)\n 280:\t\t\treturn -ENOMEM;\n 281:\t\n 282:\t\t/*\n 283:\t\t * Setup our bonding from config params.. sets up our private struct..\n 284:\t\t */\n 285:\t\tret = do_dev_config(dev, it);\n 286:\t\tif (ret)\n 287:\t\t\treturn ret;\n 288:\t\n 289:\t\tdev-\u003eboard_name = devpriv-\u003ename;\n 290:\t\n 291:\t\tret = comedi_alloc_subdevices(dev, 1);\n 292:\t\tif (ret)\n 293:\t\t\treturn ret;\n 294:\t\n 295:\t\ts = \u0026dev-\u003esubdevices[0];\n 296:\t\ts-\u003etype = COMEDI_SUBD_DIO;\n 297:\t\ts-\u003esubdev_flags = SDF_READABLE | SDF_WRITABLE;\n 298:\t\ts-\u003en_chan = devpriv-\u003enchans;\n 299:\t\ts-\u003emaxdata = 1;\n"
}

47/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 53073
							output: 28
							thoughts: 931

Thoughts:

**Analyzing Potential Focus Symbols for a String Handling Refactor**

Okay, so I need to figure out the best focus symbols for this refactoring, which replaces `strlcat` with `seq_buf` and `snprintf`. I've already checked a few files like `drm_dp_mst_topology.c`, `sound/pci/ac97/ac97_codec.c`, and some others, but those don't seem like the core of this change. Also, early boot functions like `root_nfs_cat` and `setup_arch` are out, they're too ubiquitous.

Let's see, I need to keep in mind the focus symbol criteria: avoid ubiquitous lifecycle hot-paths, target specific feature logic, and handle static inline functions properly. Since `strcat` is inlined, it's not a direct target, so I need to look for callers.

But, am I dealing primarily with *static inline helpers* here? No, this is a multi-file refactoring, so I have to analyze the non-static functions being changed. Okay, the modified C files and the functions that *are* being changed are:
- `sound/usb/card.c` -> `usb_audio_make_longname` (static, called by `snd_usb_audio_create`)
- `sound/usb/mixer.c` -> `build_connector_control` (static) / `append_ctl_name` (static)
- `drivers/input/mouse/synaptics_usb.c` -> `synusb_probe`
- `net/sunrpc/addr.c` -> `rpc_sockaddr2uaddr`
- `net/devlink/dev.c` -> `__devlink_compat_running_version` / `devlink_compat_running_version`
- `drivers/comedi/drivers/comedi_bond.c` -> `do_dev_config` / `bonding_attach`
- `fs/orangefs/orangefs-debugfs.c` -> `orangefs_prepare_debugfs_help_string`

Wait, are these static functions even *present* in vmlinux? Yes, usually they are, unless they're small and get inlined by the compiler. Functions like `usb_audio_make_longname`, `append_ctl_name`, and `do_dev_config` are potential inlining candidates. I need to make sure I don't select something that disappears! I'll check the callers of `usb_audio_make_longname` (`snd_usb_audio_create` or `usb_audio_probe`), I'll look into how `bonding_attach` calls `do_dev_config`, and I'll need to double check the caller for `build_connector_control` in `sound/usb/mixer.c` as well.

48/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "build_connector_control",
  "PathPrefix": "sound/usb"
}

Results:

{
  "Output": "sound/usb/mixer.c=2041=static int connector_mixer_resume(struct usb_mixer_elem_list *list)\n--\nsound/usb/mixer.c-2049-/* Build a mixer control for a UAC connector control (jack-detect) */\nsound/usb/mixer.c:2050:static void build_connector_control(struct usb_mixer_interface *mixer,\nsound/usb/mixer.c-2051-\t\t\t\t    const struct usbmix_name_map *imap,\n--\nsound/usb/mixer.c=2391=static int parse_audio_input_terminal(struct mixer_build *state, int unitid,\n--\nsound/usb/mixer.c-2415-\t    uac_v2v3_control_is_readable(bmctls, control))\nsound/usb/mixer.c:2416:\t\tbuild_connector_control(state-\u003emixer, state-\u003emap, \u0026iterm, true);\nsound/usb/mixer.c-2417-\n--\nsound/usb/mixer.c=3265=static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer,\n--\nsound/usb/mixer.c-3406-\t\titerm.type = UAC_BIDIR_TERMINAL_HEADSET;\nsound/usb/mixer.c:3407:\t\tbuild_connector_control(mixer, map-\u003emap, \u0026iterm, true);\nsound/usb/mixer.c-3408-\n--\nsound/usb/mixer.c-3412-\t\toterm.type = UAC_BIDIR_TERMINAL_HEADSET;\nsound/usb/mixer.c:3413:\t\tbuild_connector_control(mixer, map-\u003emap, \u0026oterm, false);\nsound/usb/mixer.c-3414-\t}\n--\nsound/usb/mixer.c=3424=static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)\n--\nsound/usb/mixer.c-3487-\t\t\t\t\t\t\t UAC2_TE_CONNECTOR)) {\nsound/usb/mixer.c:3488:\t\t\t\tbuild_connector_control(state.mixer, state.map,\nsound/usb/mixer.c-3489-\t\t\t\t\t\t\t\u0026state.oterm, false);\n--\nsound/usb/mixer.c-3513-\t\t\t\t\t\t\t UAC3_TE_INSERTION)) {\nsound/usb/mixer.c:3514:\t\t\t\tbuild_connector_control(state.mixer, state.map,\nsound/usb/mixer.c-3515-\t\t\t\t\t\t\t\u0026state.oterm, false);\n"
}

49/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 55315
							output: 36
							thoughts: 210

Thoughts:

**Analyzing Potential Optimization Bottlenecks**

Okay, so `build_connector_control` gets called all over the place, which probably means the compiler isn't inlining it. That's a good starting point for optimization. Let's see what else might be a problem.

First, I should check `rpc_sockaddr2uaddr`. Ah, it's global and non-static, *and* it's got `EXPORT_SYMBOL_GPL` – that's another function that the compiler probably can't optimize aggressively. Then there's `devlink_compat_running_version` which, again, is global and non-static, so the compiler will have trouble there.

Moving on, `synusb_probe` is a probe function and also non-inlined – that's a potential area to investigate further, since probe functions often have some overhead in them. Finally, `bonding_attach` is a driver attach callback in `comedi_bond.c`, so it may have some issues with the same issues, but let's check it regardless.

I'll check the config options for each of these: For `synusb_probe`, I need to see what's going on in the Kconfig. I can see it's linked to `CONFIG_MOUSE_SYNAPTICS_USB`, so what does *that* depend on? Let me scan those lines from 375 to 395 in `drivers/input/mouse/Kconfig` to get the context.

50/2

2026/09/15 11:11

tool

read-file

Args:

{
  "File": "drivers/input/mouse/Kconfig",
  "FirstLine": 375,
  "LineCount": 20
}

Results:

{
  "Contents": " 375:\t\n 376:\t\t  To compile this driver as a module, choose M here: the\n 377:\t\t  module will be called synaptics_i2c.\n 378:\t\n 379:\tconfig MOUSE_SYNAPTICS_USB\n 380:\t\ttristate \"Synaptics USB device support\"\n 381:\t\tdepends on USB_ARCH_HAS_HCD\n 382:\t\tselect USB\n 383:\t\thelp\n 384:\t\t  Say Y here if you want to use a Synaptics USB touchpad or pointing\n 385:\t\t  stick.\n 386:\t\n 387:\t\t  While these devices emulate an USB mouse by default and can be used\n 388:\t\t  with standard usbhid driver, this driver, together with its X.Org\n 389:\t\t  counterpart, allows you to fully utilize capabilities of the device.\n 390:\t\t  More information can be found at:\n 391:\t\t  \u003chttp://jan-steinhoff.de/linux/synaptics-usb.html\u003e\n 392:\t\n 393:\t\t  To compile this driver as a module, choose M here: the\n 394:\t\t  module will be called synaptics_usb.\n"
}

51/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 56216
							output: 29
							thoughts: 51

Thoughts:

**Examining USB Dependencies**

Okay, so I'm looking at `MOUSE_SYNAPTICS_USB` and it's pretty straightforward, depending on `USB_ARCH_HAS_HCD` and, naturally, selecting `USB`. Makes sense; that's the base requirement. My immediate thought, however, is about `SND_USB_AUDIO`. It triggers something similar in my mind. Where does that sit in the dependency chain? Let me just cross-reference the `sound/usb/Kconfig` file to see how those are related and if there are any subtle differences in their dependencies. It's important to be thorough.

52/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "config SND_USB_AUDIO",
  "PathPrefix": "sound/usb"
}

Results:

{
  "Output": "sound/usb/Kconfig=11=if SND_USB \u0026\u0026 USB\nsound/usb/Kconfig-12-\nsound/usb/Kconfig:13:config SND_USB_AUDIO\nsound/usb/Kconfig-14-\ttristate \"USB Audio/MIDI driver\"\n--\nsound/usb/Kconfig-27-\nsound/usb/Kconfig:28:config SND_USB_AUDIO_MIDI_V2\nsound/usb/Kconfig-29-\tbool \"MIDI 2.0 support by USB Audio driver\"\n--\nsound/usb/Kconfig-37-\nsound/usb/Kconfig:38:config SND_USB_AUDIO_USE_MEDIA_CONTROLLER\nsound/usb/Kconfig-39-\tbool\n--\nsound/usb/Kconfig=178=config SND_BCD2000\n--\nsound/usb/Kconfig-190-\nsound/usb/Kconfig:191:config SND_USB_AUDIO_QMI\nsound/usb/Kconfig-192-\ttristate \"Qualcomm Audio Offload driver\"\n"
}

53/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 56702
							output: 29
							thoughts: 73

Thoughts:

**Kernel Configuration Dependencies: A Quick Mental Audit**

Okay, so I'm looking at these kernel options and tracing their dependencies. *SND_USB_AUDIO* is clearly reliant on *SND_USB*, *USB*, and, implicitly, *SND* itself – that's straightforward enough. Now, I need to make sure I haven't missed any edge cases. *SUNRPC* – that's the one I need to consider next. *CONFIG_SUNRPC* is pretty much a given for any NFS or RPC setup, so no surprises there. Just confirming it's accounted for. Alright, next on the list. What about *COMEDI_BOND*? Let me double-check its dependencies. Time to go right to the source. I'll need to check the *drivers/comedi/Kconfig* file to make certain I'm not missing anything critical there. Gotta make sure I'm not accidentally enabling something without its required foundations.

54/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "COMEDI_BOND",
  "PathPrefix": "drivers/comedi"
}

Results:

{
  "Output": "drivers/comedi/Kconfig=43=if COMEDI_MISC_DRIVERS\ndrivers/comedi/Kconfig-44-\ndrivers/comedi/Kconfig:45:config COMEDI_BOND\ndrivers/comedi/Kconfig-46-\ttristate \"Comedi device bonding support\"\n--\ndrivers/comedi/drivers/Makefile=8=obj-$(CONFIG_COMEDI_ISADMA)\t\t+= comedi_isadma.o\n--\ndrivers/comedi/drivers/Makefile-10-# Comedi misc drivers\ndrivers/comedi/drivers/Makefile:11:obj-$(CONFIG_COMEDI_BOND)\t\t+= comedi_bond.o\ndrivers/comedi/drivers/Makefile-12-obj-$(CONFIG_COMEDI_TEST)\t\t+= comedi_test.o\n"
}

55/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 57213
							output: 34
							thoughts: 22

Thoughts:

Here's my take on those lines from `drivers/comedi/Kconfig`:

**Examining the Comedi Driver Configuration**

Okay, let's zero in on lines 40-60 of the `drivers/comedi/Kconfig` file. I'm focusing on this specific block because it's likely defining a specific set of options or dependencies within the Comedi (Control and Measurement Device Interface) framework. Given my expertise, I'm immediately looking for a few key things: What hardware or functionality is this section related to? Are there any sub-options being introduced, or is this a conditional inclusion based on some other kernel configuration? Are there any obvious potential conflicts or dependencies I need to be aware of? Are there any hints about the target platform or use case being described? I'll be particularly attentive to the `depends on` statements and any `select` directives, as they are essential clues to the relationships between features. Knowing the context of this configuration fragment could be critical when troubleshooting device driver issues or adapting the Comedi subsystem for a customized setup. I'm ready to dive into the specifics and decipher the logic here.

56/2

2026/09/15 11:11

tool

read-file

Args:

{
  "File": "drivers/comedi/Kconfig",
  "FirstLine": 40,
  "LineCount": 25
}

Results:

{
  "Contents": "  40:\t\t  kernel: saying N will just cause the configurator to skip all\n  41:\t\t  the questions about misc non-hardware comedi drivers.\n  42:\t\n  43:\tif COMEDI_MISC_DRIVERS\n  44:\t\n  45:\tconfig COMEDI_BOND\n  46:\t\ttristate \"Comedi device bonding support\"\n  47:\t\tselect COMEDI_KCOMEDILIB\n  48:\t\thelp\n  49:\t\t  Enable support for a driver to 'bond' (merge) multiple subdevices\n  50:\t\t  from multiple devices together as one.\n  51:\t\n  52:\t\t  Currently, it only handles digital I/O subdevices.\n  53:\t\n  54:\t\t  To compile this driver as a module, choose M here: the module will be\n  55:\t\t  called comedi_bond.\n  56:\t\n  57:\tconfig COMEDI_TEST\n  58:\t\ttristate \"Fake waveform generator support\"\n  59:\t\thelp\n  60:\t\t  Enable support for the fake waveform generator.\n  61:\t\t  This driver is mainly for testing purposes, but can also be used to\n  62:\t\t  generate sample waveforms on systems that don't have data acquisition\n  63:\t\t  hardware.\n  64:\t\n"
}

57/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 57849
							output: 26
							thoughts: 103

Thoughts:

**My Configuration Quandary**

Okay, so I'm looking at `COMEDI_BOND`. Right off the bat, I know it needs `COMEDI_MISC_DRIVERS` and `COMEDI` to function. That's a given. But my mind is wandering... what's the relationship with `CONFIG_NET` and `CONFIG_NET_DEVLINK`? I'm thinking about network dependencies here. I know `CONFIG_NET` has a hand in enabling devlink – that's the code in `net/devlink/`. That's important to consider.

And then my thoughts shift gears... what about `FORTIFY_SOURCE`? Is there some interplay there? I know `CONFIG_FORTIFY_SOURCE` gives us those fortified string helpers. I should probably double-check where that is defined... better to look at the source. I'll take a look at `CONFIG_FORTIFY_SOURCE` within `security/Kconfig`. I'll want to see how the settings are defined.

58/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "config FORTIFY_SOURCE",
  "PathPrefix": "security"
}

Results:

{
  "Output": "security/Kconfig.hardening=212=menu \"Bounds checking\"\nsecurity/Kconfig.hardening-213-\nsecurity/Kconfig.hardening:214:config FORTIFY_SOURCE\nsecurity/Kconfig.hardening-215-\tbool \"Harden common str/mem functions against buffer overflows\"\n"
}

59/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 58281
							output: 30
							thoughts: 36

Thoughts:

Okay, here's my interpretation of that thought process, tailored for an expert audience, and rendered in the first person:

**Investigating the OrangeFS Filesystem Configuration**

Right, let's see what's happening with the OrangeFS filesystem. My first instinct is to get a handle on its configuration. Specifically, I need to check the relevant Kconfig file. I'm going to look in the `fs/orangefs/Kconfig` directory to find the configuration options. That's where all the fundamental options should be defined. And specifically, I'm thinking I need to find `CONFIG_ORANGEFS_FS`. That's the primary, presumably boolean, flag that enables or disables the entire filesystem. Understanding this option is critical to understanding the OrangeFS build and behavior, particularly if I'm troubleshooting or customizing it. This is a good starting point, and I expect it will likely provide some insight, either direction.

60/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "config ORANGEFS_FS",
  "PathPrefix": "fs/orangefs"
}

Results:

{
  "Output": "fs/orangefs/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/orangefs/Kconfig:2:config ORANGEFS_FS\nfs/orangefs/Kconfig-3-\ttristate \"ORANGEFS (Powered by PVFS) support\"\n"
}

61/2

2026/09/15 11:11

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 58623
							output: 32
							thoughts: 52

Thoughts:

**Investigating DRM_DISPLAY_DP_HELPER**

Okay, let's dive in. My immediate thought is to check out `DRM_DISPLAY_DP_HELPER`. Where does this come into play? I need to get a handle on its scope. My focus is on the `drivers/gpu/drm/display` area, so I'm thinking the relevant code is probably located there. Specifically, I'm thinking about the file `drm_dp_mst_topology.c`. It makes sense this would be connected since it involves the MST topology, and helper functions often play a role in managing that.

Now, my next question is: How is `drm_dp_mst_topology.c` actually compiled and integrated? I need to understand the configuration process. What specific config options are required to get that file included in the build? Knowing that will give me a better understanding of how `DRM_DISPLAY_DP_HELPER` relates to the broader display stack configuration. I need to trace this back.

62/2

2026/09/15 11:11

tool

grepper

Args:

{
  "Expression": "drm_dp_mst_topology",
  "PathPrefix": "drivers/gpu/drm"
}

Results:

{
  "Output": "\nFull output is too long, showing 500 out of 1531 lines.\nUse more precise expression if possible.\n\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h=644=struct amdgpu_mst_connector {\n--\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h-646-\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h:647:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/amdgpu/amdgpu_mode.h-648-\tstruct amdgpu_dm_dp_aux dm_dp_aux;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1167=static int dm_late_init(struct amdgpu_ip_block *ip_block)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1217-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1218:static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1219-{\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1269=static void s3_handle_mst(struct drm_device *dev, bool suspend)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1273-\tstruct drm_connector_list_iter iter;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1274:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1275-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1289-\t\tif (suspend) {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1290:\t\t\tdrm_dp_mst_topology_mgr_suspend(mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-1291-\t\t} else {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=1838=static int dm_resume(struct amdgpu_ip_block *ip_block)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-2046-\t\telse\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:2047:\t\t\tdrm_dp_mst_topology_queue_probe(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-2048-\t}\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=6109=static int amdgpu_dm_atomic_check(struct drm_device *dev,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-6125-\tstruct dm_crtc_state *dm_old_crtc_state, *dm_new_crtc_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:6126:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:6127:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-6128-\tstruct dsc_mst_fairness_vars vars[MAX_PIPES] = {0};\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h=797=struct amdgpu_dm_connector {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h-825-\t/* DM only */\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:826:\tstruct drm_dp_mst_topology_mgr mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h-827-\tstruct amdgpu_dm_dp_aux dm_dp_aux;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=97=STATIC_IFN_KUNIT int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-105-\tconst struct drm_display_mode *adjusted_mode = \u0026crtc_state-\u003eadjusted_mode;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:106:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-107-\tstruct drm_dp_mst_port *mst_port;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:108:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-109-\tenum dc_color_depth color_depth;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=299=int amdgpu_dm_detect_mst_link_for_all_connectors(struct drm_device *dev)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-318-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:319:\t\t\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-320-\t\t\tif (ret \u003c 0) {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c=1890=STATIC_IFN_KUNIT void amdgpu_dm_connector_destroy(struct drm_connector *connector)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-1900-\tif (aconnector-\u003emst_mgr.dev)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c:1901:\t\tdrm_dp_mst_topology_mgr_destroy(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c-1902-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=348=static bool dp_mst_is_end_device(struct amdgpu_dm_connector *aconnector)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-350-\tbool is_end_device = false;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:351:\tstruct drm_dp_mst_topology_mgr *mgr = NULL;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-352-\tstruct drm_dp_mst_port *port = NULL;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=2831=static int dp_is_mst_connector_show(struct seq_file *m, void *unused)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-2834-\tstruct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:2835:\tstruct drm_dp_mst_topology_mgr *mgr = NULL;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-2836-\tstruct drm_dp_mst_port *port = NULL;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c=4260=static int trigger_hpd_mst_set(void *data, u64 val)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4282-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:4283:\t\t\t\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4284-\t\t\t\tif (ret \u003c 0)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4299-\t\t\tdc_link_dp_receiver_power_ctrl(link, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c:4300:\t\t\tdrm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_root-\u003emst_mgr, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c-4301-\t\t\tlink-\u003emst_stream_alloc_table.stream_count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=311=STATIC_IFN_KUNIT void dm_helpers_construct_old_payload(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:312:\t\t\tstruct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:313:\t\t\tstruct drm_dp_mst_topology_state *mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-314-\t\t\tstruct drm_dp_mst_atomic_payload *new_payload,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=347=bool dm_helpers_dp_mst_write_payload_allocation_table(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-353-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:354:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-355-\tstruct drm_dp_mst_atomic_payload *target_payload, *new_payload, old_payload;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:356:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-357-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-368-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:369:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-370-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=419=enum act_return_status dm_helpers_dp_mst_poll_for_allocation_change_trigger(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-423-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:424:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-425-\tint ret;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=446=void dm_helpers_dp_mst_send_payload_allocation(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-450-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:451:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:452:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-453-\tstruct drm_dp_mst_atomic_payload *new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-463-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:464:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-465-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=481=void dm_helpers_dp_mst_update_mst_mgr_for_deallocation(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-485-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:486:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:487:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-488-\tstruct drm_dp_mst_atomic_payload *new_payload, old_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-497-\tmst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:498:\tmst_state = to_drm_dp_mst_topology_state(mst_mgr-\u003ebase.state);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-499-\tnew_payload = drm_atomic_get_mst_payload_state(mst_state, aconnector-\u003emst_output_port);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=601=bool dm_helpers_dp_mst_start_top_mgr(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-622-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:623:\tret = drm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, true);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-624-\tif (ret \u003c 0) {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c=636=bool dm_helpers_dp_mst_stop_top_mgr(\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-650-\tif (aconnector-\u003emst_mgr.mst_state == true) {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:651:\t\tdrm_dp_mst_topology_mgr_set_mst(\u0026aconnector-\u003emst_mgr, false);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c-652-\t\tlink-\u003ecur_link_settings.lane_count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h=19=struct drm_dp_mst_atomic_payload;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:20:struct drm_dp_mst_topology_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:21:struct drm_dp_mst_topology_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-22-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h=32=void fill_dc_mst_payload_table_from_drm(struct dc_link *link,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-35-\t\t\t\t\t struct dc_dp_mst_stream_allocation_table *table);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:36:void dm_helpers_construct_old_payload(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h:37:\t\t\t\t      struct drm_dp_mst_topology_state *mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.h-38-\t\t\t\t      struct drm_dp_mst_atomic_payload *new_payload,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=607=STATIC_IFN_KUNIT int dm_dp_mst_atomic_check(struct drm_connector *connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-610-\tstruct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:611:\tstruct drm_dp_mst_topology_mgr *mst_mgr = \u0026aconnector-\u003emst_root-\u003emst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-612-\tstruct drm_dp_mst_port *mst_port = aconnector-\u003emst_output_port;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=659=static struct drm_connector *\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:660:dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-661-\t\t\tstruct drm_dp_mst_port *port,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=780=void dm_handle_mst_sideband_msg_ready_event(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:781:\tstruct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-782-\tenum mst_msg_ready_type msg_rdy_type)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=863=EXPORT_IF_KUNIT(dm_handle_mst_sideband_msg_ready_event);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-864-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:865:STATIC_IFN_KUNIT void dm_handle_mst_down_rep_msg_ready(struct drm_dp_mst_topology_mgr *mgr)\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-866-{\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=869=EXPORT_IF_KUNIT(dm_handle_mst_down_rep_msg_ready);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-870-\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:871:static const struct drm_dp_mst_topology_cbs dm_mst_cbs = {\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-872-\t.add_connector = dm_dp_add_mst_connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=876=void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-898-\taconnector-\u003emst_mgr.cbs = \u0026dm_mst_cbs;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:899:\tdrm_dp_mst_topology_mgr_init(\u0026aconnector-\u003emst_mgr, adev_to_drm(dm-\u003eadev),\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-900-\t\t\t\t     \u0026aconnector-\u003edm_dp_aux.aux, 16, 4, aconnector-\u003econnector_id);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1039=static int increase_dsc_bpp(struct drm_atomic_commit *state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1040:\t\t\t    struct drm_dp_mst_topology_state *mst_state,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1041-\t\t\t    struct dc_link *dc_link,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1307=static int compute_mst_dsc_configs_for_link(struct drm_atomic_commit *state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1310-\t\t\t\t\t    struct dsc_mst_fairness_vars *vars,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1311:\t\t\t\t\t    struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1312-\t\t\t\t\t    int *link_vars_start_index)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1316-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1317:\tstruct drm_dp_mst_topology_state *mst_state = drm_atomic_get_mst_topology_state(state, mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1318-\tint count = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1611=int compute_mst_dsc_configs_for_state(struct drm_atomic_commit *state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1618-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1619:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1620-\tstruct resource_pool *res_pool;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c=1681=static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_commit *state,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1688-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c:1689:\tstruct drm_dp_mst_topology_mgr *mst_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c-1690-\tint link_vars_start_index = 0;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=67=struct drm_atomic_commit;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:68:struct drm_dp_mst_topology_mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-69-\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=79=void dm_handle_mst_sideband_msg_ready_event(\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:80:\tstruct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-81-\tenum mst_msg_ready_type msg_rdy_type);\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h=113=void dm_mst_select_esi_dpcd(u8 dpcd_rev, int *dpcd_addr, u8 *dpcd_bytes_to_read);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h:114:void dm_handle_mst_down_rep_msg_ready(struct drm_dp_mst_topology_mgr *mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h-115-struct drm_encoder *dm_mst_atomic_best_encoder(struct drm_connector *connector,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c=2861=static void dm_test_detect_mst_non_mst_link(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c-2885- * The condition short-circuits on a NULL mst_mgr.aux, so the real\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c:2886: * drm_dp_mst_topology_mgr_set_mst() path is never reached.\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c-2887- */\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=2948=static void dm_test_construct_old_payload_empty_list(struct kunit *test)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2949-{\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2950:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2951:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2952-\tstruct drm_dp_mst_atomic_payload *new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=2984=static void dm_test_construct_old_payload_intervening(struct kunit *test)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2985-{\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2986:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:2987:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-2988-\tstruct drm_dp_mst_atomic_payload *new_payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3033=static void dm_test_write_payload_alloc_table_success(struct kunit *test,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3037-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3038:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3039:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3040-\tstruct drm_dp_mst_atomic_payload *payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3144=static ssize_t dm_test_act_aux_transfer_fail(struct drm_dp_aux *aux,\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3154- * With a connector-backed link and a failing AUX channel, the non-boot\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3155: * path calls drm_dp_mst_topology_mgr_set_mst(true), which fails to read the\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3156- * DPCD caps and returns a negative error, so the helper returns false.\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3158=static void dm_test_mst_start_top_mgr_set_mst_fail(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3189- *\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3190: * With mst_state set, the helper calls drm_dp_mst_topology_mgr_set_mst(false)\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3191- * to disable MST and clears the link lane count. The helper always returns\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3340=static void dm_test_mst_send_payload_alloc_part2_fail(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3343-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3344:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3345:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3346-\tstruct drm_dp_mst_atomic_payload *payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c=3402=static void dm_test_mst_update_mgr_dealloc_success(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3404-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3405:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c:3406:\tstruct drm_dp_mst_topology_state *mst_state;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c-3407-\tstruct drm_dp_mst_atomic_payload *payload;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=499=static void dm_mst_test_retrieve_branch_reads_oui(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-501-\tstruct amdgpu_dm_connector *aconnector;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:502:\tstruct drm_dp_mst_topology_mgr *mgr;\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-503-\tstruct drm_dp_mst_branch *branch;\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=1132=static const struct drm_connector_funcs dm_mst_test_connector_funcs = {\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1145- * eDP early return, including dc_link_dp_get_max_link_enc_cap() and\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:1146: * drm_dp_mst_topology_mgr_init(). A fully initialized DRM mode config and\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1147- * connector are required because the topology manager registers a private\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c=1150=static void dm_mst_test_initialize_dp_connector_mst(struct kunit *test)\n--\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1195-\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c:1196:\tdrm_dp_mst_topology_mgr_destroy(\u0026aconnector-\u003emst_mgr);\ndrivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c-1197-\tdrm_dp_cec_unregister_connector(\u0026aconnector-\u003edm_dp_aux.aux);\n--\ndrivers/gpu/drm/display/Makefile=8=drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += \\\n--\ndrivers/gpu/drm/display/Makefile-10-\tdrm_dp_helper.o \\\ndrivers/gpu/drm/display/Makefile:11:\tdrm_dp_mst_topology.o\ndrivers/gpu/drm/display/Makefile-12-drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TUNNEL) += \\\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-51-#include \"drm_dp_helper_internal.h\"\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:52:#include \"drm_dp_mst_topology_internal.h\"\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-53-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=61=struct drm_dp_pending_up_req {\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-66-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:67:static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-68-\t\t\t\t  char *buf);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-69-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:70:static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-71-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:72:static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-73-\t\t\t\t struct drm_dp_mst_port *port,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-74-\t\t\t\t int offset, int size, u8 *bytes);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:75:static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-76-\t\t\t\t  struct drm_dp_mst_port *port,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-78-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:79:static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-80-\t\t\t\t    struct drm_dp_mst_branch *mstb);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=82=static void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:83:drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-84-\t\t\t\t   struct drm_dp_mst_branch *mstb);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-85-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:86:static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-87-\t\t\t\t\t   struct drm_dp_mst_branch *mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-88-\t\t\t\t\t   struct drm_dp_mst_port *port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:89:static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-90-\t\t\t\t guid_t *guid);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=93=static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:94:static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-95-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=283=static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-302-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:303:static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-304-\t\t\t\t\t   struct drm_dp_sideband_msg_hdr *hdr,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=788=static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-818-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:819:static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-820-\t\t\t\t\t       struct drm_dp_sideband_msg_rx *raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1003=drm_dp_sideband_parse_query_stream_enc_status(\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1037-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1038:static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1039-\t\t\t\t\tstruct drm_dp_sideband_msg_rx *raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1084=static bool\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1085:drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1086-\t\t\t\t\t       struct drm_dp_sideband_msg_rx *raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1113-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1114:static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1115-\t\t\t\t\t\t\t struct drm_dp_sideband_msg_rx *raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1137-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1138:static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1139-\t\t\t\t      struct drm_dp_sideband_msg_rx *raw,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1235=build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1252-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1253:static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1254-\t\t\t      struct drm_dp_sideband_msg_tx *txmsg)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1268=static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1270-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1271:\tstruct drm_dp_mst_topology_mgr *mgr = mstb-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1272-\tunsigned long wait_timeout = msecs_to_jiffies(4000);\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1487=static void drm_dp_free_mst_port(struct kref *kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1507- * ensure that they grab at least one main malloc reference to their MST ports\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1508: * in \u0026drm_dp_mst_topology_cbs.add_connector. This callback is called before\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1509- * there is any chance for \u0026drm_dp_mst_port.malloc_kref to reach 0.\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1543=static noinline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1544:__topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1545:\t\t    struct drm_dp_mst_topology_ref_history *history,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1546:\t\t    enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1547-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1548:\tstruct drm_dp_mst_topology_ref_entry *entry = NULL;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1549-\tdepot_stack_handle_t backtrace;\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1568-\tif (!entry) {\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1569:\t\tstruct drm_dp_mst_topology_ref_entry *new;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1570-\t\tint new_len = history-\u003elen + 1;\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1590=topology_ref_history_cmp(const void *a, const void *b)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1591-{\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1592:\tconst struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1593-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1602=static inline const char *\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1603:topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1604-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1612=__dump_topology_ref_history(struct drm_device *drm,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1613:\t\t\t    struct drm_dp_mst_topology_ref_history *history,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1614-\t\t\t    void *ptr, const char *type_str)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1635-\tfor (i = 0; i \u003c history-\u003elen; i++) {\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1636:\t\tconst struct drm_dp_mst_topology_ref_entry *entry =\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1637-\t\t\t\u0026history-\u003eentries[i];\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1670=save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1671:\t\t       enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1672-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1677=save_port_topology_ref(struct drm_dp_mst_port *port,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1678:\t\t       enum drm_dp_mst_topology_ref_type type)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1679-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1683=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1684:topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1685-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1689=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1690:topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1691-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1695=static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1696:topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1697-static inline void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1698:topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1699-static inline void\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1707=struct drm_dp_mst_atomic_payload *\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1708:drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1709-\t\t\t\t struct drm_dp_mst_port *port)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1721=static void drm_dp_destroy_mst_branch_device(struct kref *kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1724-\t\tcontainer_of(kref, struct drm_dp_mst_branch, topology_kref);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1725:\tstruct drm_dp_mst_topology_mgr *mgr = mstb-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1726-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1741-/**\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1742: * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1743- * branch device unless it's zero\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1752- * reference to @mstb. If you already have a topology reference to @mstb, you\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1753: * should use drm_dp_mst_topology_get_mstb() instead.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1754- *\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1755- * See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1756: * drm_dp_mst_topology_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1757: * drm_dp_mst_topology_put_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1758- *\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1763=static int __must_check\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1764:drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1765-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1780-/**\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1781: * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1782- * branch device\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1787- * you are already guaranteed to have at least one active topology reference\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1788: * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1789- *\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1790- * See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1791: * drm_dp_mst_topology_try_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1792: * drm_dp_mst_topology_put_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1793- */\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1794:static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1795-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1806-/**\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1807: * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1808- * device\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1814- * See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1815: * drm_dp_mst_topology_try_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1816: * drm_dp_mst_topology_get_mstb()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1817- */\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1818=static void\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1819:drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1820-{\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=1830=static void drm_dp_destroy_port(struct kref *kref)\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1833-\t\tcontainer_of(kref, struct drm_dp_mst_port, topology_kref);\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1834:\tstruct drm_dp_mst_topology_mgr *mgr = port-\u003emgr;\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1835-\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1856-/**\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1857: * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1858- * port unless it's zero\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1867- * reference to @port. If you already have a topology reference to @port, you\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1868: * should use drm_dp_mst_topology_get_port() instead.\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1869- *\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1870- * See also:\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1871: * drm_dp_mst_topology_get_port()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:1872: * drm_dp_mst_topology_put_port()\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-1873- *\n--\n\n"
}

63/2

2026/09/15 11:12

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 75127
							output: 268
							thoughts: 1864

Thoughts:

**Fuzzing Target Identification: A Focused Approach**

Okay, so I've been digging into this code, and it looks like `drm_dp_mst_port_add_connector` calls `build_mst_prop_path`, which is related to DP MST. However, syzkaller doesn't typically touch DP MST, so that's a dead end for now.

But wait! I've found some much more promising avenues: the USB audio and mixer code (`sound/usb/card.c`, `sound/usb/mixer.c`) are directly reachable through syzkaller's USB fuzzing capabilities, along with Synaptics USB mouse (`drivers/input/mouse/synaptics_usb.c`). Furthermore, RPC via sockets (`net/sunrpc/addr.c`) and devlink functionality via ethtool ioctls (`net/devlink/dev.c`) look like prime targets. Finally, I noticed the Comedi bond driver (`drivers/comedi/drivers/comedi_bond.c`) can be exercised through comedi ioctls.

So, let's nail down what functions are relevant here:

I see `usb_audio_make_longname` is marked as static, but it could be inlined. I can list both `usb_audio_make_longname` and `snd_usb_audio_create`, since the latter will likely be the actual symbol, if the compiler inlines it! I'm adding `build_connector_control`, `synusb_probe`, `rpc_sockaddr2uaddr`, `devlink_compat_running_version`, and `bonding_attach`, as well. These are directly reachable.

Now, I'll identify the required kernel config flags: `SND_USB_AUDIO`, `MOUSE_SYNAPTICS_USB`, `SUNRPC`, `NET`, and `COMEDI` along with `COMEDI_BOND` and `COMEDI_MISC_DRIVERS`. It looks like `COMEDI_MISC_DRIVERS` enables the `COMEDI_BOND` menu. `SND_USB` and `USB` are needed to enable `SND_USB_AUDIO`, while `MOUSE_SYNAPTICS_USB` needs `USB_ARCH_HAS_HCD` and `USB`, and is under `INPUT_MOUSE`, which depends on `INPUT`.

I need to confirm these functions are good candidates. Let's make sure that none of these identified symbols are ubiquitous hot paths. Okay, these are specific to the altered code and reachable subsystems: not general memory allocators, page fault handlers, locks, or scheduling primitives. Great, good to go!

I will note that `fs/orangefs/orangefs-debugfs.c`, `sound/pci/ac97/ac97_codec.c`, `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c`, `drivers/edac/thunderx_edac.c` and architectures are in the diff, but they are not necessarily immediately reachable.

The key reachable areas on amd64 in virtual environments are:
- USB audio (`sound/usb/card.c`, `sound/usb/mixer.c`)
- USB synaptics mouse (`drivers/input/mouse/synaptics_usb.c`)
- SunRPC (`net/sunrpc/addr.c`)
- Devlink (`net/devlink/dev.c`)
- Comedi bond (`drivers/comedi/drivers/comedi_bond.c`)

Now, everything seems thoroughly vetted, and ready to go with `set-results`.

64/2

2026/09/15 11:12

tool

set-results

Args:

{
  "EnableConfigs": [
    "SND_USB_AUDIO",
    "MOUSE_SYNAPTICS_USB",
    "SUNRPC",
    "COMEDI_BOND",
    "COMEDI_MISC_DRIVERS",
    "COMEDI",
    "FORTIFY_SOURCE"
  ],
  "FocusSymbols": [
    "usb_audio_make_longname",
    "snd_usb_audio_create",
    "build_connector_control",
    "synusb_probe",
    "rpc_sockaddr2uaddr",
    "devlink_compat_running_version",
    "bonding_attach"
  ],
  "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.",
  "WorthFuzzing": true
}

Results:

{
  "EnableConfigs": [
    "SND_USB_AUDIO",
    "MOUSE_SYNAPTICS_USB",
    "SUNRPC",
    "COMEDI_BOND",
    "COMEDI_MISC_DRIVERS",
    "COMEDI",
    "FORTIFY_SOURCE"
  ],
  "FocusSymbols": [
    "usb_audio_make_longname",
    "snd_usb_audio_create",
    "build_connector_control",
    "synusb_probe",
    "rpc_sockaddr2uaddr",
    "devlink_compat_running_version",
    "bonding_attach"
  ],
  "Reasoning": "The patch refactors string manipulation across multiple kernel subsystems and drivers, replacing strlcat with seq_buf and snprintf patterns. Several affected components reside in reachable subsystems on amd64 in virtualized fuzzing environments (including USB gadget/emulation drivers such as snd-usb-audio and synaptics_usb, SunRPC universal address translation, netlink devlink compat version retrieval, and comedi bonding). These refactorings modify string sizing and buffer logic in reachable execution paths, warranting fuzzing to ensure no truncation, off-by-one, or buffer overflow regressions are introduced.",
  "WorthFuzzing": true
}

65/1

2026/09/15 11:12

action

10m

Args:

{
  "WorthFuzzing": true
}

Results:

null

66/2

2026/09/15 11:12

agent

kmsan-evaluator

10m

Model:

core

Args:

null

Results:

{
  "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

Instruction:

You are an expert Linux kernel security engineer specializing in kernel memory
error detectors (KASAN and KMSAN). Your job is to review the provided patch series and
determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer)
fuzzing session in addition to standard KASAN fuzzing.

CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN:
- Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable
  a comprehensive suite of debugging tools and sanitizers, including KASAN
  (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP
  (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks.
- KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap,
  or page allocations) and kernel-to-user memory info-leaks.

Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN,
LOCKDEP, OR OTHER STANDARD BUG DETECTORS.
A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY
set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks
that are detected ONLY by KMSAN.

Look holistically at the patch series and surrounding code. Even if no direct
uninitialized field accesses or new buffer allocations are added in the diff itself,
a patch may alter control flow, bounds checking, or data length calculations in ways
that change how the rest of the code operates on existing buffers (e.g. allowing
uninitialized stack/heap memory to be read, copied to user space, or used in control
flow). Do not hesitate to use your code access tools to inspect the surrounding code,
called functions, and callers.

Set NeedsKMSAN=true ONLY IF the patch introduces or modifies:
1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb
   attributes, ioctl output arguments, socket options, or BPF buffers) where fields
   or structure padding might not be fully initialized/zeroed.
2. Conditional logic or branching that depends on potentially uninitialized variables
   or struct fields.
3. Allocation or initialization of complex data structures where uninitialized fields
   could be read later in reachable code paths.
4. Bounds checks, lengths, or logic in a way that allows surrounding code to access
   uninitialized bytes of existing buffers.

Set NeedsKMSAN=false IF:
- The code changes primarily risk out-of-bounds access, array overflows, NULL pointer
  dereferences, locking deadlocks, or use-after-free bugs (these are already caught
  by KASAN, LOCKDEP, or standard bug detectors).
- All stack/heap structures touched or introduced by the patch are fully zeroed
  or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied.
- The patch does not introduce any risk of uninitialized memory usage or info-leaks.

Use your code access tools to inspect the surrounding code if necessary, then provide
detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch.
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Prompt:

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit 7af038477662f04c34c484a45e1a571280e5f258
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Sep 15 11:08:01 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
index 4ec591bde3dfa..21140b44d96e6 100644
--- a/arch/arm/kernel/atags_parse.c
+++ b/arch/arm/kernel/atags_parse.c
@@ -121,9 +121,10 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
 static int __init parse_tag_cmdline(const struct tag *tag)
 {
 #if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
-	strlcat(default_command_line, tag->u.cmdline.cmdline,
-		COMMAND_LINE_SIZE);
+	size_t len = strlen(default_command_line);
+
+	snprintf(default_command_line + len, COMMAND_LINE_SIZE - len,
+		 " %s", tag->u.cmdline.cmdline);
 #elif defined(CONFIG_CMDLINE_FORCE)
 	pr_warn("Ignoring tag cmdline (using the default kernel command line)\n");
 #else
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 6fa4a22a58fd6..826396f141b9c 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -33,6 +33,7 @@
 #include <linux/of_address.h>
 #include <linux/suspend.h>
 #include <linux/swiotlb.h>
+#include <linux/seq_buf.h>
 
 #include <asm/addrspace.h>
 #include <asm/alternative.h>
@@ -305,6 +306,8 @@ static void __init fdt_setup(void)
 
 static void __init bootcmdline_init(char **cmdline_p)
 {
+	struct seq_buf s;
+
 	/*
 	 * If CONFIG_CMDLINE_FORCE is enabled then initializing the command line
 	 * is trivial - we simply use the built-in command line unconditionally &
@@ -315,6 +318,11 @@ static void __init bootcmdline_init(char **cmdline_p)
 		goto out;
 	}
 
+	/* Initialize seq_buf pointing to boot_command_line */
+	s.buffer = boot_command_line;
+	s.size = COMMAND_LINE_SIZE;
+	s.len = strlen(boot_command_line);
+
 #ifdef CONFIG_OF_FLATTREE
 	/*
 	 * If CONFIG_CMDLINE_BOOTLOADER is enabled and we are in FDT-based system,
@@ -323,11 +331,11 @@ static void __init bootcmdline_init(char **cmdline_p)
 	 * to boot_command_line.
 	 */
 	if (initial_boot_params) {
-		if (boot_command_line[0])
-			strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+		if (s.len)
+			seq_buf_puts(&s, " ");
 
-		if (!strstr(boot_command_line, init_command_line))
-			strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE);
+		if (!strstr(s.buffer, init_command_line))
+			seq_buf_puts(&s, init_command_line);
 
 		goto out;
 	}
@@ -338,14 +346,14 @@ static void __init bootcmdline_init(char **cmdline_p)
 	 * CONFIG_CMDLINE_EXTEND is enabled.
 	 */
 	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) && CONFIG_CMDLINE[0]) {
-		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
-		strlcat(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+		seq_buf_puts(&s, " ");
+		seq_buf_puts(&s, CONFIG_CMDLINE);
 	}
 
 	/*
 	 * Use built-in command line if the bootloader command line is empty.
 	 */
-	if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !boot_command_line[0])
+	if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !s.len)
 		strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 
 out:
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 1ae6d0c0e1d67..0d9c2137d6758 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -518,13 +518,28 @@ static void __init check_kernel_sections_mem(void)
 
 static void __init bootcmdline_append(const char *s, size_t max)
 {
+	size_t len;
+	int prec;
+
 	if (!s[0] || !max)
 		return;
 
-	if (boot_command_line[0])
-		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+	len = strlen(boot_command_line);
+	if (len >= COMMAND_LINE_SIZE - 1)
+		return;
 
-	strlcat(boot_command_line, s, max);
+	if (len) {
+		if (COMMAND_LINE_SIZE - len < 3)
+			return;
+
+		prec = min_t(size_t, max, COMMAND_LINE_SIZE - len - 2);
+		snprintf(boot_command_line + len, COMMAND_LINE_SIZE - len, " %.*s",
+			 prec, s);
+	} else {
+		prec = min_t(size_t, max, COMMAND_LINE_SIZE - 1);
+		snprintf(boot_command_line, COMMAND_LINE_SIZE, "%.*s",
+			 prec, s);
+	}
 }
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index d3e17a7a89016..fa3efc82ad874 100644
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/console.h>
 #include <linux/seq_file.h>
+#include <linux/seq_buf.h>
 #define PCI_DEBUG
 #include <linux/pci.h>
 #undef PCI_DEBUG
@@ -42,6 +43,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE];
 static void __init setup_cmdline(char **cmdline_p)
 {
 	extern unsigned int boot_args[];
+	struct seq_buf s;
 	char *p;
 
 	*cmdline_p = command_line;
@@ -54,19 +56,21 @@ static void __init setup_cmdline(char **cmdline_p)
 	strscpy(boot_command_line, (char *)__va(boot_args[1]),
 		COMMAND_LINE_SIZE);
 
+	s.buffer = boot_command_line;
+	s.size = COMMAND_LINE_SIZE;
+	s.len = strlen(boot_command_line);
+
 	/* autodetect console type (if not done by palo yet) */
 	p = boot_command_line;
 	if (!str_has_prefix(p, "console=") && !strstr(p, " console=")) {
-		strlcat(p, " console=", COMMAND_LINE_SIZE);
-		if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
-			strlcat(p, "ttyS0", COMMAND_LINE_SIZE);
-		else
-			strlcat(p, "tty0", COMMAND_LINE_SIZE);
+		seq_buf_printf(&s, " console=%s",
+			       PAGE0->mem_cons.cl_class == CL_DUPLEX ?
+			       "ttyS0" : "tty0");
 	}
 
 	/* default to use early console */
 	if (!strstr(p, "earlycon"))
-		strlcat(p, " earlycon=pdc", COMMAND_LINE_SIZE);
+		seq_buf_printf(&s, " earlycon=pdc");
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* did palo pass us a ramdisk? */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index cda6adb9f69c4..c40e0edd7c136 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -916,9 +916,11 @@ void __init setup_arch(char **cmdline_p)
 #else
 	if (builtin_cmdline[0]) {
 		/* append boot loader cmdline to builtin */
-		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
-		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
-		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+		char tmp[COMMAND_LINE_SIZE];
+
+		snprintf(tmp, COMMAND_LINE_SIZE, "%s %s", builtin_cmdline, boot_command_line);
+		strscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE);
+		strscpy(boot_command_line, tmp, COMMAND_LINE_SIZE);
 	}
 #endif
 	builtin_cmdline_added = true;
diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
index 8e10ecab4f0dc..a10cfbd04c728 100644
--- a/drivers/comedi/drivers/comedi_bond.c
+++ b/drivers/comedi/drivers/comedi_bond.c
@@ -39,6 +39,7 @@
 
 #include <linux/module.h>
 #include <linux/string.h>
+#include <linux/seq_buf.h>
 #include <linux/slab.h>
 #include <linux/comedi.h>
 #include <linux/comedi/comedilib.h>
@@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 {
 	struct comedi_bond_private *devpriv = dev->private;
 	DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
+	struct seq_buf s;
 	int i;
 
 	memset(&devs_opened, 0, sizeof(devs_opened));
-	devpriv->name[0] = 0;
+	seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
 	/*
 	 * Loop through all comedi devices specified on the command-line,
 	 * building our device list.
@@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 			}
 			devpriv->devs = devs;
 			devpriv->devs[devpriv->ndevs++] = bdev;
-			{
-				/* Append dev:subdev to devpriv->name */
-				char buf[20];
-
-				snprintf(buf, sizeof(buf), "%u:%u ",
-					 bdev->minor, bdev->subdev);
-				strlcat(devpriv->name, buf,
-					sizeof(devpriv->name));
-			}
+
+			/* Append dev:subdev to devpriv->name */
+			seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
 		}
 	}
 
@@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
 		return -EINVAL;
 	}
 
+	seq_buf_str(&s);
+
 	return 0;
 }
 
diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index 9c0a1e48f96f2..4e3781815b6d7 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/bitfield.h>
 #include <linux/circ_buf.h>
+#include <linux/seq_buf.h>
 
 #include <asm/page.h>
 
@@ -47,12 +48,17 @@ static void decode_register(char *str, size_t size,
 {
 	int ret = 0;
 
+	if (size > 0)
+		str[0] = '\0';
+
 	while (descr->type && descr->mask && descr->descr) {
 		if (reg & descr->mask) {
 			ret = snprintf(str, size, "\n\t%s, %s",
 				       descr->type == ERR_CORRECTED ?
 					 "Corrected" : "Uncorrected",
 				       descr->descr);
+			if (ret < 0 || ret >= size)
+				break;
 			str += ret;
 			size -= ret;
 		}
@@ -1115,35 +1121,37 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(ocx->com_ring_head, ocx->com_ring_tail,
 			ARRAY_SIZE(ocx->com_err_ctx))) {
+		struct seq_buf s;
+
 		tail = ring_pos(ocx->com_ring_tail,
 				ARRAY_SIZE(ocx->com_err_ctx));
 		ctx = &ocx->com_err_ctx[tail];
 
-		snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx",
-			ocx->edac_dev->ctl_name, ctx->reg_com_int);
+		seq_buf_init(&s, msg, OCX_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx",
+			       ocx->edac_dev->ctl_name, ctx->reg_com_int);
 
 		decode_register(other, OCX_OTHER_SIZE,
 				ocx_com_errors, ctx->reg_com_int);
 
-		strlcat(msg, other, OCX_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		for (lane = 0; lane < OCX_RX_LANES; lane++)
 			if (ctx->reg_com_int & BIT(lane)) {
-				snprintf(other, OCX_OTHER_SIZE,
-					 "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx",
-					 lane, ctx->reg_lane_int[lane],
-					 lane, ctx->reg_lane_stat11[lane]);
-
-				strlcat(msg, other, OCX_MESSAGE_SIZE);
+				seq_buf_printf(&s,
+					       "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx",
+					       lane, ctx->reg_lane_int[lane],
+					       lane, ctx->reg_lane_stat11[lane]);
 
 				decode_register(other, OCX_OTHER_SIZE,
 						ocx_lane_errors,
 						ctx->reg_lane_int[lane]);
-				strlcat(msg, other, OCX_MESSAGE_SIZE);
+				seq_buf_puts(&s, other);
 			}
 
 		if (ctx->reg_com_int & OCX_COM_INT_CE)
-			edac_device_handle_ce(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 
 		ocx->com_ring_tail++;
 	}
@@ -1196,25 +1204,28 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(ocx->link_ring_head, ocx->link_ring_tail,
 			ARRAY_SIZE(ocx->link_err_ctx))) {
+		struct seq_buf s;
+
 		tail = ring_pos(ocx->link_ring_head,
 				ARRAY_SIZE(ocx->link_err_ctx));
 
 		ctx = &ocx->link_err_ctx[tail];
 
-		snprintf(msg, OCX_MESSAGE_SIZE,
-			 "%s: OCX_COM_LINK_INT[%d]: %016llx",
-			 ocx->edac_dev->ctl_name,
-			 ctx->link, ctx->reg_com_link_int);
+		seq_buf_init(&s, msg, OCX_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: OCX_COM_LINK_INT[%d]: %016llx",
+			       ocx->edac_dev->ctl_name,
+			       ctx->link, ctx->reg_com_link_int);
 
 		decode_register(other, OCX_OTHER_SIZE,
 				ocx_com_link_errors, ctx->reg_com_link_int);
 
-		strlcat(msg, other, OCX_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		if (ctx->reg_com_link_int & OCX_COM_LINK_INT_UE)
-			edac_device_handle_ue(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ue(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 		else if (ctx->reg_com_link_int & OCX_COM_LINK_INT_CE)
-			edac_device_handle_ce(ocx->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(ocx->edac_dev, 0, 0, seq_buf_str(&s));
 
 		ocx->link_ring_tail++;
 	}
@@ -1880,19 +1891,25 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(l2c->ring_head, l2c->ring_tail,
 			ARRAY_SIZE(l2c->err_ctx))) {
-		snprintf(msg, L2C_MESSAGE_SIZE,
-			 "%s: %s: %016llx, %s: %016llx",
-			 l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int,
-			 ctx->reg_ext_name, ctx->reg_ext);
+		struct seq_buf s;
+
+		tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx));
+		ctx = &l2c->err_ctx[tail];
+
+		seq_buf_init(&s, msg, L2C_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: %s: %016llx, %s: %016llx",
+			       l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int,
+			       ctx->reg_ext_name, ctx->reg_ext);
 
 		decode_register(other, L2C_OTHER_SIZE, l2_errors, ctx->reg_int);
 
-		strlcat(msg, other, L2C_MESSAGE_SIZE);
+		seq_buf_puts(&s, other);
 
 		if (ctx->reg_int & mask_ue)
-			edac_device_handle_ue(l2c->edac_dev, 0, 0, msg);
+			edac_device_handle_ue(l2c->edac_dev, 0, 0, seq_buf_str(&s));
 		else if (ctx->reg_int & mask_ce)
-			edac_device_handle_ce(l2c->edac_dev, 0, 0, msg);
+			edac_device_handle_ce(l2c->edac_dev, 0, 0, seq_buf_str(&s));
 
 		l2c->ring_tail++;
 	}
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 7ce9e212770ad..229b5fec44bff 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -29,6 +29,7 @@
 #include <linux/kernel.h>
 #include <linux/random.h>
 #include <linux/sched.h>
+#include <linux/seq_buf.h>
 #include <linux/seq_file.h>
 
 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
@@ -2216,19 +2217,21 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
 				char *proppath,
 				size_t proppath_size)
 {
+	struct seq_buf s;
 	int i;
-	char temp[8];
 
-	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
+	seq_buf_init(&s, proppath, proppath_size);
+
+	seq_buf_printf(&s, "mst:%d", mstb->mgr->conn_base_id);
 	for (i = 0; i < (mstb->lct - 1); i++) {
 		int shift = (i % 2) ? 0 : 4;
 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
 
-		snprintf(temp, sizeof(temp), "-%d", port_num);
-		strlcat(proppath, temp, proppath_size);
+		seq_buf_printf(&s, "-%d", port_num);
 	}
-	snprintf(temp, sizeof(temp), "-%d", pnum);
-	strlcat(proppath, temp, proppath_size);
+	seq_buf_printf(&s, "-%d", pnum);
+
+	seq_buf_str(&s);
 }
 
 /**
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
index 0f242db775e1c..548a50f744224 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/seq_buf.h>
 
 #include <drm/drm_print.h>
 #include <drm/drm_debugfs.h>
@@ -376,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 	char engines[128];
+	struct seq_buf s;
+	const char *s_str;
 
-	engines[0] = '\0';
+	seq_buf_init(&s, engines, sizeof(engines));
 
 	if (group < num_groups) {
 		for_each_hw_engine(hwe, gt, id) {
@@ -385,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 			u16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe);
 			u32 mask = groups[group].engines[guc_class];
 
-			if (mask & BIT(guc_logical_instance)) {
-				strlcat(engines, hwe->name, sizeof(engines));
-				strlcat(engines, " ", sizeof(engines));
-			}
+			if (mask & BIT(guc_logical_instance))
+				seq_buf_printf(&s, "%s ", hwe->name);
 		}
-		strlcat(engines, "\n", sizeof(engines));
+		seq_buf_puts(&s, "\n");
 	}
 
-	return simple_read_from_buffer(buf, count, ppos, engines, strlen(engines));
+	s_str = seq_buf_str(&s);
+	return simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));
 }
 
 static const struct file_operations sched_group_engines_fops = {
@@ -663,15 +665,15 @@ static ssize_t control_write(struct file *file, const char __user *buf, size_t c
 static ssize_t control_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	char help[128];
+	struct seq_buf s;
 	size_t n;
 
-	help[0] = '\0';
+	seq_buf_init(&s, help, sizeof(help));
 	for (n = 0; n < ARRAY_SIZE(control_cmds); n++) {
-		strlcat(help, control_cmds[n].cmd, sizeof(help));
-		strlcat(help, "\n", sizeof(help));
+		seq_buf_printf(&s, "%s\n", control_cmds[n].cmd);
 	}
 
-	return simple_read_from_buffer(buf, count, ppos, help, strlen(help));
+	return simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s));
 }
 
 static const struct file_operations control_ops = {
diff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c
index 880a0c79148cd..d13d2d6202ee5 100644
--- a/drivers/input/mouse/synaptics_usb.c
+++ b/drivers/input/mouse/synaptics_usb.c
@@ -41,6 +41,7 @@
 #include <linux/usb.h>
 #include <linux/input.h>
 #include <linux/usb/input.h>
+#include <linux/seq_buf.h>
 
 #define USB_VENDOR_ID_SYNAPTICS	0x06cb
 #define USB_DEVICE_ID_SYNAPTICS_TP	0x0001	/* Synaptics USB TouchPad */
@@ -278,6 +279,8 @@ static int synusb_probe(struct usb_interface *intf,
 	struct input_dev *input_dev;
 	unsigned int intf_num = intf->cur_altsetting->desc.bInterfaceNumber;
 	unsigned int altsetting = min(intf->num_altsetting, 1U);
+	struct seq_buf s;
+	char path[64];
 	int error;
 
 	error = usb_set_interface(udev, intf_num, altsetting);
@@ -334,27 +337,29 @@ static int synusb_probe(struct usb_interface *intf,
 			 ep->bInterval);
 	synusb->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 
+	seq_buf_init(&s, synusb->name, sizeof(synusb->name));
+
 	if (udev->manufacturer)
-		strscpy(synusb->name, udev->manufacturer,
-			sizeof(synusb->name));
+		seq_buf_puts(&s, udev->manufacturer);
 
 	if (udev->product) {
 		if (udev->manufacturer)
-			strlcat(synusb->name, " ", sizeof(synusb->name));
-		strlcat(synusb->name, udev->product, sizeof(synusb->name));
+			seq_buf_puts(&s, " ");
+		seq_buf_puts(&s, udev->product);
 	}
 
-	if (!strlen(synusb->name))
-		snprintf(synusb->name, sizeof(synusb->name),
-			 "USB Synaptics Device %04x:%04x",
-			 le16_to_cpu(udev->descriptor.idVendor),
-			 le16_to_cpu(udev->descriptor.idProduct));
+	if (!seq_buf_used(&s))
+		seq_buf_printf(&s, "USB Synaptics Device %04x:%04x",
+			       le16_to_cpu(udev->descriptor.idVendor),
+			       le16_to_cpu(udev->descriptor.idProduct));
 
 	if (synusb->flags & SYNUSB_STICK)
-		strlcat(synusb->name, " (Stick)", sizeof(synusb->name));
+		seq_buf_puts(&s, " (Stick)");
+
+	seq_buf_str(&s);
 
-	usb_make_path(udev, synusb->phys, sizeof(synusb->phys));
-	strlcat(synusb->phys, "/input0", sizeof(synusb->phys));
+	usb_make_path(udev, path, sizeof(path));
+	snprintf(synusb->phys, sizeof(synusb->phys), "%s/input0", path);
 
 	input_dev->name = synusb->name;
 	input_dev->phys = synusb->phys;
diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
index f1241b63aa5ce..bd15eb58fc84f 100644
--- a/drivers/media/dvb-frontends/si2165.c
+++ b/drivers/media/dvb-frontends/si2165.c
@@ -1243,20 +1243,17 @@ static int si2165_probe(struct i2c_client *client)
 		chip_name, rev_char, state->chip_type,
 		state->chip_revcode);
 
-	strlcat(state->fe.ops.info.name, chip_name,
-		sizeof(state->fe.ops.info.name));
+	snprintf(state->fe.ops.info.name, sizeof(state->fe.ops.info.name),
+		 "Silicon Labs %s%s%s",
+		 chip_name,
+		 state->has_dvbt ? " DVB-T" : "",
+		 state->has_dvbc ? " DVB-C" : "");
 
 	n = 0;
-	if (state->has_dvbt) {
+	if (state->has_dvbt)
 		state->fe.ops.delsys[n++] = SYS_DVBT;
-		strlcat(state->fe.ops.info.name, " DVB-T",
-			sizeof(state->fe.ops.info.name));
-	}
-	if (state->has_dvbc) {
+	if (state->has_dvbc)
 		state->fe.ops.delsys[n++] = SYS_DVBC_ANNEX_A;
-		strlcat(state->fe.ops.info.name, " DVB-C",
-			sizeof(state->fe.ops.info.name));
-	}
 
 	/* return fe pointer */
 	*pdata->fe = &state->fe;
diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index 1b6a8fbaa6485..9f792128a0efe 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -1059,19 +1059,26 @@ static inline char *i40e_nvm_version_str(struct i40e_hw *hw, char *buf,
 					 size_t len)
 {
 	char ver[16] = " ";
+	size_t offset;
 
 	/* Get NVM version */
 	i40e_info_nvm_ver(hw, buf, len);
 
 	/* Append EETrackID if provided */
 	i40e_info_eetrack(hw, &ver[1], sizeof(ver) - 1);
-	if (strlen(ver) > 1)
-		strlcat(buf, ver, len);
+	if (strlen(ver) > 1) {
+		offset = strlen(buf);
+		if (offset < len)
+			snprintf(buf + offset, len - offset, "%s", ver);
+	}
 
 	/* Append combo image version if provided */
 	i40e_info_civd_ver(hw, &ver[1], sizeof(ver) - 1);
-	if (strlen(ver) > 1)
-		strlcat(buf, ver, len);
+	if (strlen(ver) > 1) {
+		offset = strlen(buf);
+		if (offset < len)
+			snprintf(buf + offset, len - offset, "%s", ver);
+	}
 
 	return buf;
 }
diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c
index 479b2418ca340..fcc9e9eb57322 100644
--- a/drivers/net/wireless/ath/wil6210/wmi.c
+++ b/drivers/net/wireless/ath/wil6210/wmi.c
@@ -7,6 +7,7 @@
 #include <linux/moduleparam.h>
 #include <linux/etherdevice.h>
 #include <linux/if_arp.h>
+#include <linux/seq_buf.h>
 
 #include "wil6210.h"
 #include "txrx.h"
@@ -3162,27 +3163,30 @@ int wmi_suspend(struct wil6210_priv *wil)
 
 static void resume_triggers2string(u32 triggers, char *string, int str_size)
 {
-	string[0] = '\0';
+	struct seq_buf s;
+
+	seq_buf_init(&s, string, str_size);
 
 	if (!triggers) {
-		strlcat(string, " UNKNOWN", str_size);
-		return;
-	}
+		seq_buf_puts(&s, " UNKNOWN");
+	} else {
+		if (triggers & WMI_RESUME_TRIGGER_HOST)
+			seq_buf_puts(&s, " HOST");
 
-	if (triggers & WMI_RESUME_TRIGGER_HOST)
-		strlcat(string, " HOST", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_UCAST_RX)
+			seq_buf_puts(&s, " UCAST_RX");
 
-	if (triggers & WMI_RESUME_TRIGGER_UCAST_RX)
-		strlcat(string, " UCAST_RX", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_BCAST_RX)
+			seq_buf_puts(&s, " BCAST_RX");
 
-	if (triggers & WMI_RESUME_TRIGGER_BCAST_RX)
-		strlcat(string, " BCAST_RX", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_WMI_EVT)
+			seq_buf_puts(&s, " WMI_EVT");
 
-	if (triggers & WMI_RESUME_TRIGGER_WMI_EVT)
-		strlcat(string, " WMI_EVT", str_size);
+		if (triggers & WMI_RESUME_TRIGGER_DISCONNECT)
+			seq_buf_puts(&s, " DISCONNECT");
+	}
 
-	if (triggers & WMI_RESUME_TRIGGER_DISCONNECT)
-		strlcat(string, " DISCONNECT", str_size);
+	seq_buf_str(&s);
 }
 
 int wmi_resume(struct wil6210_priv *wil)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index 22ff326f1924a..2f74a952599ec 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
@@ -845,22 +845,17 @@ brcmf_fw_alloc_request(u32 chip, u32 chiprev,
 	fwreq->n_items = n_fwnames;
 
 	for (j = 0; j < n_fwnames; j++) {
-		fwreq->items[j].path = fwnames[j].path;
-		fwnames[j].path[0] = '\0';
 		/* check if firmware path is provided by module parameter */
 		if (brcmf_mp_global.firmware_path[0] != '\0') {
-			strscpy(fwnames[j].path, mp_path,
-				BRCMF_FW_NAME_LEN);
-
-			if (end != '/') {
-				strlcat(fwnames[j].path, "/",
-					BRCMF_FW_NAME_LEN);
-			}
+			snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s",
+				 mp_path, (end == '/') ? "" : "/",
+				 mapping_table[i].fw_base,
+				 fwnames[j].extension);
+		} else {
+			snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s",
+				 mapping_table[i].fw_base,
+				 fwnames[j].extension);
 		}
-		strlcat(fwnames[j].path, mapping_table[i].fw_base,
-			BRCMF_FW_NAME_LEN);
-		strlcat(fwnames[j].path, fwnames[j].extension,
-			BRCMF_FW_NAME_LEN);
 		fwreq->items[j].path = fwnames[j].path;
 	}
 
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index a64afc3ded3d4..311021a83f03e 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 	const void *rng_seed;
 	const void *fdt = initial_boot_params;
 
+	if (!fdt)
+		goto handle_cmdline;
+
 	node = fdt_path_offset(fdt, "/chosen");
 	if (node < 0)
 		node = fdt_path_offset(fdt, "/chosen@0");
@@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char *cmdline)
 	 */
 #ifdef CONFIG_CMDLINE
 #if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
-	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+	{
+		size_t len = strlen(cmdline);
+
+		if (len < COMMAND_LINE_SIZE)
+			snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE);
+	}
 #elif defined(CONFIG_CMDLINE_FORCE)
 	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #else
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
index 5ecc9ed4c44db..0d639eec689c0 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.c
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
@@ -1155,8 +1155,7 @@ static void samsung_banks_node_get(struct device *dev, struct samsung_pinctrl_dr
 
 	bank = d->pin_banks;
 	for (i = 0; i < d->nr_banks; ++i, ++bank) {
-		strscpy(node_name, bank->name, sizeof(node_name));
-		len = strlcat(node_name, suffix, sizeof(node_name));
+		len = snprintf(node_name, sizeof(node_name), "%s%s", bank->name, suffix);
 		if (len >= sizeof(node_name)) {
 			dev_err(dev, "Too long pin bank name '%s', ignoring\n",
 				bank->name);
diff --git a/drivers/scsi/bfa/bfa_fcs.c b/drivers/scsi/bfa/bfa_fcs.c
index 9b57312f43f50..9fe0343c0b321 100644
--- a/drivers/scsi/bfa/bfa_fcs.c
+++ b/drivers/scsi/bfa/bfa_fcs.c
@@ -760,49 +760,26 @@ bfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s *fabric)
 
 	bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model);
 
-	/* Model name/number */
-	strscpy(port_cfg->sym_name.symname, model,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
-	/* Driver Version */
-	strlcat(port_cfg->sym_name.symname, driver_info->version,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
-	/* Host machine name */
-	strlcat(port_cfg->sym_name.symname,
-		driver_info->host_machine_name,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->sym_name.symname, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-		BFA_SYMNAME_MAXLEN);
-
 	/*
 	 * Host OS Info :
 	 * If OS Patch Info is not there, do not truncate any bytes from the
 	 * OS name string and instead copy the entire OS info string (64 bytes).
 	 */
 	if (driver_info->host_os_patch[0] == '\0') {
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_name,
-			BFA_SYMNAME_MAXLEN);
-		strlcat(port_cfg->sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
+		snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN,
+			 "%s%s%s%s%s%s%s%s",
+			 model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);
 	} else {
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_name,
-			BFA_SYMNAME_MAXLEN);
-		strlcat(port_cfg->sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-		/* Append host OS Patch Info */
-		strlcat(port_cfg->sym_name.symname,
-			driver_info->host_os_patch,
-			BFA_SYMNAME_MAXLEN);
+		snprintf(port_cfg->sym_name.symname, BFA_SYMNAME_MAXLEN,
+			 "%s%s%s%s%s%s%s%s%s",
+			 model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->version, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+			 driver_info->host_os_patch);
 	}
 
 	/* null terminate */
@@ -821,30 +798,13 @@ bfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s *fabric)
 
 	bfa_ioc_get_adapter_model(&fabric->fcs->bfa->ioc, model);
 
-	/* Model name/number */
-	strscpy(port_cfg->node_sym_name.symname, model,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* Driver Version */
-	strlcat(port_cfg->node_sym_name.symname, (char *)driver_info->version,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* Host machine name */
-	strlcat(port_cfg->node_sym_name.symname,
-		driver_info->host_machine_name,
-		BFA_SYMNAME_MAXLEN);
-	strlcat(port_cfg->node_sym_name.symname,
-			BFA_FCS_PORT_SYMBNAME_SEPARATOR,
-			BFA_SYMNAME_MAXLEN);
-
-	/* null terminate */
-	port_cfg->node_sym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;
+	/* Model name/number, Driver Version, Host machine name */
+	snprintf(port_cfg->node_sym_name.symname, BFA_SYMNAME_MAXLEN,
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR
+		 "%s" BFA_FCS_PORT_SYMBNAME_SEPARATOR,
+		 model, (char *)driver_info->version,
+		 driver_info->host_machine_name);
 }
 
 /*
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 432612d224374..a28208414aec2 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -173,12 +173,15 @@ static int __init root_nfs_cat(char *dest, const char *src,
 			       const size_t destlen)
 {
 	size_t len = strlen(dest);
+	int ret;
 
-	if (len && dest[len - 1] != ',')
-		if (strlcat(dest, ",", destlen) >= destlen)
-			return -1;
+	if (len >= destlen)
+		return -1;
+
+	ret = snprintf(dest + len, destlen - len, "%s%s",
+		       (len && dest[len - 1] != ',') ? "," : "", src);
 
-	if (strlcat(dest, src, destlen) >= destlen)
+	if (ret < 0 || ret >= destlen - len)
 		return -1;
 	return 0;
 }
diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c
index 9f94919a6bc62..6e2f9887eab4b 100644
--- a/fs/orangefs/orangefs-debugfs.c
+++ b/fs/orangefs/orangefs-debugfs.c
@@ -37,6 +37,7 @@
  */
 #include <linux/debugfs.h>
 #include <linux/slab.h>
+#include <linux/seq_buf.h>
 
 #include <linux/uaccess.h>
 
@@ -623,10 +624,10 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 	char *client_title = "Client Debug Keywords:\n";
 	char *kernel_title = "Kernel Debug Keywords:\n";
 	size_t string_size =  DEBUG_HELP_STRING_SIZE;
-	size_t result_size;
 	size_t i;
 	char *new;
 	int rc = -EINVAL;
+	struct seq_buf s;
 
 	gossip_debug(GOSSIP_UTILS_DEBUG, "%s: start\n", __func__);
 
@@ -640,17 +641,14 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 		goto out;
 	}
 
+	seq_buf_init(&s, new, string_size);
+
 	/*
-	 * strlcat(dst, src, size) will append at most
-	 * "size - strlen(dst) - 1" bytes of src onto dst,
-	 * null terminating the result, and return the total
-	 * length of the string it tried to create.
-	 *
 	 * We'll just plow through here building our new debug
-	 * help string and let strlcat take care of assuring that
+	 * help string and let seq_buf take care of assuring that
 	 * dst doesn't overflow.
 	 */
-	strlcat(new, client_title, string_size);
+	seq_buf_puts(&s, client_title);
 
 	if (!at_boot) {
 
@@ -665,24 +663,18 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 			goto out;
 		}
 
-		for (i = 0; i < cdm_element_count; i++) {
-			strlcat(new, "\t", string_size);
-			strlcat(new, cdm_array[i].keyword, string_size);
-			strlcat(new, "\n", string_size);
-		}
+		for (i = 0; i < cdm_element_count; i++)
+			seq_buf_printf(&s, "\t%s\n", cdm_array[i].keyword);
 	}
 
-	strlcat(new, "\n", string_size);
-	strlcat(new, kernel_title, string_size);
+	seq_buf_puts(&s, "\n");
+	seq_buf_puts(&s, kernel_title);
 
-	for (i = 0; i < num_kmod_keyword_mask_map; i++) {
-		strlcat(new, "\t", string_size);
-		strlcat(new, s_kmod_keyword_mask_map[i].keyword, string_size);
-		result_size = strlcat(new, "\n", string_size);
-	}
+	for (i = 0; i < num_kmod_keyword_mask_map; i++)
+		seq_buf_printf(&s, "\t%s\n", s_kmod_keyword_mask_map[i].keyword);
 
 	/* See if we tried to put too many bytes into "new"... */
-	if (result_size >= string_size) {
+	if (seq_buf_has_overflowed(&s)) {
 		kfree(new);
 		goto out;
 	}
@@ -692,7 +684,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot)
 	} else {
 		mutex_lock(&orangefs_help_file_lock);
 		memset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE);
-		strlcat(debug_help_string, new, string_size);
+		strscpy(debug_help_string, new, DEBUG_HELP_STRING_SIZE);
 		mutex_unlock(&orangefs_help_file_lock);
 		kfree(new);
 	}
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index cf841dc71feff..0b489124bfcb8 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
 char *strcat(char * const POS p, const char *q)
 {
 	const size_t p_size = __member_size(p);
-	const size_t wanted = strlcat(p, q, p_size);
+
+	if (p_size == SIZE_MAX)
+		return __underlying_strcat(p, q);
+
+	const size_t p_len = __fortify_strlen(p);
+	const size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, "%s", q);
 
 	if (p_size <= wanted)
 		fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p);
diff --git a/net/devlink/dev.c b/net/devlink/dev.c
index 55959b0ff5ab4..987b071345c41 100644
--- a/net/devlink/dev.c
+++ b/net/devlink/dev.c
@@ -5,6 +5,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/seq_buf.h>
 #include <net/genetlink.h>
 #include <net/sock.h>
 #include "devl_internal.h"
@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 {
 	struct devlink_info_req req = {};
 	const struct nlattr *nlattr;
+	struct seq_buf s;
 	struct sk_buff *msg;
 	int rem, err;
 
@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 	if (err)
 		goto free_msg;
 
+	seq_buf_init(&s, buf, len);
+	s.len = strnlen(buf, len);
+
 	nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,
 			       (void *)msg->data, msg->len, rem) {
 		const struct nlattr *kv;
@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 
 		nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,
 					 nlattr, rem_kv) {
-			strlcat(buf, nla_data(kv), len);
-			strlcat(buf, " ", len);
+			seq_buf_printf(&s, "%s ", (const char *)nla_data(kv));
 		}
 	}
 free_msg:
diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c
index 97ff11973c493..a1e4173e5a538 100644
--- a/net/sunrpc/addr.c
+++ b/net/sunrpc/addr.c
@@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(rpc_pton);
  */
 char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 {
-	char portbuf[RPCBIND_MAXUADDRPLEN];
 	char addrbuf[RPCBIND_MAXUADDRLEN];
 	unsigned short port;
+	size_t len;
 
 	switch (sap->sa_family) {
 	case AF_INET:
-		if (rpc_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
+		len = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));
+		if (len == 0 || len >= sizeof(addrbuf))
 			return NULL;
 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
 		break;
 	case AF_INET6:
-		if (rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
+		len = rpc_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf));
+		if (len == 0 || len >= sizeof(addrbuf))
 			return NULL;
 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 		break;
@@ -283,11 +285,8 @@ char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 		return NULL;
 	}
 
-	if (snprintf(portbuf, sizeof(portbuf),
-		     ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf))
-		return NULL;
-
-	if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf))
+	if (snprintf(addrbuf + len, sizeof(addrbuf) - len,
+		     ".%u.%u", port >> 8, port & 0xff) >= sizeof(addrbuf) - len)
 		return NULL;
 
 	return kstrdup(addrbuf, gfp_flags);
@@ -352,3 +351,4 @@ size_t rpc_uaddr2sockaddr(struct net *net, const char *uaddr,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rpc_uaddr2sockaddr);
+
diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
index 0bb65be021d97..e145099ee02a9 100644
--- a/sound/pci/ac97/ac97_codec.c
+++ b/sound/pci/ac97/ac97_codec.c
@@ -1850,10 +1850,12 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,
 
 	pid = look_for_codec_id(snd_ac97_codec_ids, id);
 	if (pid) {
-		strlcat(name, " ", maxlen);
-		strlcat(name, pid->name, maxlen);
+		int l = strlen(name);
+
 		if (pid->mask != 0xffffffff)
-			sprintf(name + strlen(name), " rev %u", id & ~pid->mask);
+			snprintf(name + l, maxlen - l, " %s rev %u", pid->name, id & ~pid->mask);
+		else
+			snprintf(name + l, maxlen - l, " %s", pid->name);
 		if (ac97 && pid->patch) {
 			if ((modem && (pid->flags & AC97_MODEM_PATCH)) ||
 			    (! modem && ! (pid->flags & AC97_MODEM_PATCH)))
@@ -1861,6 +1863,7 @@ void snd_ac97_get_name(struct snd_ac97 *ac97, unsigned int id, char *name,
 		}
 	} else {
 		int l = strlen(name);
+
 		snprintf(name + l, maxlen - l, " id %x", id & 0xff);
 	}
 }
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 9307da95efbef..bdca8085fca66 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -25,6 +25,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/seq_buf.h>
 #include <linux/ctype.h>
 #include <linux/usb.h>
 #include <linux/moduleparam.h>
@@ -651,7 +652,9 @@ static void usb_audio_make_longname(struct usb_device *dev,
 	struct snd_card *card = chip->card;
 	const struct usb_audio_device_name *preset;
 	const char *s = NULL;
-	int len;
+	struct seq_buf sb;
+	char *buf;
+	size_t size;
 
 	preset = lookup_device_name(chip->usb_id);
 
@@ -667,44 +670,61 @@ static void usb_audio_make_longname(struct usb_device *dev,
 		s = preset->vendor_name;
 	else if (quirk && quirk->vendor_name)
 		s = quirk->vendor_name;
-	*card->longname = 0;
+
+	seq_buf_init(&sb, card->longname, sizeof(card->longname));
+
 	if (s && *s)
-		strscpy(card->longname, s);
+		seq_buf_puts(&sb, s);
 	else if (dev->manufacturer && *dev->manufacturer)
-		strscpy(card->longname, dev->manufacturer);
-
-	if (*card->longname) {
-		strim(card->longname);
-		if (*card->longname)
-			strlcat(card->longname, " ", sizeof(card->longname));
+		seq_buf_puts(&sb, dev->manufacturer);
+
+	if (seq_buf_used(&sb)) {
+		char *trimmed;
+
+		seq_buf_str(&sb);
+		trimmed = strim(card->longname);
+		if (trimmed != card->longname)
+			memmove(card->longname, trimmed, strlen(trimmed) + 1);
+		sb.len = strlen(card->longname);
+		if (sb.len)
+			seq_buf_putc(&sb, ' ');
 	}
 
-	strlcat(card->longname, card->shortname, sizeof(card->longname));
+	seq_buf_puts(&sb, card->shortname);
 
-	len = strlcat(card->longname, " at ", sizeof(card->longname));
+	seq_buf_puts(&sb, " at ");
 
-	if (len < sizeof(card->longname))
-		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
+	size = seq_buf_get_buf(&sb, &buf);
+	if (size > 0) {
+		int path_len = usb_make_path(dev, buf, size);
+
+		if (path_len >= 0)
+			seq_buf_commit(&sb, path_len);
+		else
+			seq_buf_set_overflow(&sb);
+	}
 
 	switch (snd_usb_get_speed(dev)) {
 	case USB_SPEED_LOW:
-		strlcat(card->longname, ", low speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", low speed");
 		break;
 	case USB_SPEED_FULL:
-		strlcat(card->longname, ", full speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", full speed");
 		break;
 	case USB_SPEED_HIGH:
-		strlcat(card->longname, ", high speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", high speed");
 		break;
 	case USB_SPEED_SUPER:
-		strlcat(card->longname, ", super speed", sizeof(card->longname));
+		seq_buf_puts(&sb, ", super speed");
 		break;
 	case USB_SPEED_SUPER_PLUS:
-		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
+		seq_buf_puts(&sb, ", super speed plus");
 		break;
 	default:
 		break;
 	}
+
+	seq_buf_str(&sb);
 }
 
 static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ecaa8bc08d7ca..f64ecad4e77ea 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1722,7 +1722,11 @@ const struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
  */
 static size_t append_ctl_name(struct snd_kcontrol *kctl, const char *str)
 {
-	return strlcat(kctl->id.name, str, sizeof(kctl->id.name));
+	size_t len = strlen(kctl->id.name);
+
+	if (len >= sizeof(kctl->id.name))
+		return len + strlen(str);
+	return len + snprintf(kctl->id.name + len, sizeof(kctl->id.name) - len, "%s", str);
 }
 
 /*
@@ -2090,7 +2094,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer,
 	}
 
 	if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name)))
-		strlcat(kctl->id.name, " Jack", sizeof(kctl->id.name));
+		append_ctl_name(kctl, " Jack");
 	else
 		get_connector_control_name(mixer, term, is_input, kctl->id.name,
 					   sizeof(kctl->id.name));

67/3

2026/09/15 11:12

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 19908
							output: 37
							thoughts: 644

Thoughts:

**Analyzing the `strlcat` Deprecation Patch**

Okay, so this patch is aimed at removing `strlcat` from the kernel, a good move overall. The general approach seems to be replacing it with safer alternatives like `snprintf`, `seq_buf`, and `strscpy`. Now, my job is to make sure this is done correctly and doesn't introduce any new vulnerabilities, like uninitialized memory issues or information leaks. Let's go through these changes file by file.

First up, `arch/arm/kernel/atags_parse.c`. They've replaced the `strlcat` calls with `snprintf`. Seems straightforward: calculating the current length of `default_command_line` and then using `snprintf` to append the new content. Looks safe, as long as `COMMAND_LINE_SIZE` is handled properly.

Next, `arch/loongarch/kernel/setup.c` introduces a `seq_buf`. Smart, using a `seq_buf` is a much cleaner way to build a string, it's safer.  `s.buffer = boot_command_line; s.size = COMMAND_LINE_SIZE; s.len = strlen(boot_command_line);` looks fine.

In `arch/mips/kernel/setup.c` and `arch/parisc/kernel/setup.c`, again, they're using `snprintf` and `seq_buf` respectively, similar to the previous cases. Looks good; consistent application of the replacement strategy.

Now, `arch/x86/kernel/setup.c` has a slightly more complex approach. They're using `snprintf` to build a temporary buffer (`tmp`) and then copying it back to the target strings (`builtin_cmdline` and `boot_command_line`) using `strscpy`. The temporary buffer is crucial here; `snprintf` will null-terminate it, which makes `strscpy` safe. It's a bit more overhead, but it's a valid way to handle this.

Okay, now for `drivers/comedi/drivers/comedi_bond.c`.  They've replaced  `devpriv->name[0] = 0;` with `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));`. Wait, before, it was null-terminating the `devpriv->name` string. However, they now initialize a `seq_buf` struct to point at `devpriv->name`. Before I can make a decision, let me check the memory allocation for `devpriv`. I'm concerned about the initialization, or lack thereof. Let's go check the allocation of `devpriv` in this file. It is a critical step, but not yet complete.

68/3

2026/09/15 11:12

tool

grepper

Args:

{
  "Expression": "devpriv = ",
  "PathPrefix": "drivers/comedi/drivers/comedi_bond.c"
}

Results:

{
  "Output": "drivers/comedi/drivers/comedi_bond.c=62=static int bonding_dio_insn_bits(struct comedi_device *dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-65-{\ndrivers/comedi/drivers/comedi_bond.c:66:\tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-67-\tunsigned int n_left, n_done, base_chan;\n--\ndrivers/comedi/drivers/comedi_bond.c=125=static int bonding_dio_insn_config(struct comedi_device *dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-128-{\ndrivers/comedi/drivers/comedi_bond.c:129:\tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-130-\tunsigned int chan = CR_CHAN(insn-\u003echanspec);\n--\ndrivers/comedi/drivers/comedi_bond.c=170=static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)\ndrivers/comedi/drivers/comedi_bond.c-171-{\ndrivers/comedi/drivers/comedi_bond.c:172:\tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-173-\tDECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);\n--\ndrivers/comedi/drivers/comedi_bond.c=271=static int bonding_attach(struct comedi_device *dev,\n--\ndrivers/comedi/drivers/comedi_bond.c-277-\ndrivers/comedi/drivers/comedi_bond.c:278:\tdevpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));\ndrivers/comedi/drivers/comedi_bond.c-279-\tif (!devpriv)\n--\ndrivers/comedi/drivers/comedi_bond.c=312=static void bonding_detach(struct comedi_device *dev)\ndrivers/comedi/drivers/comedi_bond.c-313-{\ndrivers/comedi/drivers/comedi_bond.c:314:\tstruct comedi_bond_private *devpriv = dev-\u003eprivate;\ndrivers/comedi/drivers/comedi_bond.c-315-\n"
}

69/3

2026/09/15 11:12

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 21824
							output: 34
							thoughts: 106

Thoughts:

**Analyzing the Memory Allocation and Initialization**

Okay, so `comedi_alloc_devpriv` is using `kzalloc`. That's good; clear, zeroed memory is always a solid starting point. Now, looking at this next line, `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));` I see it's initializing `s`. Specifically, `s.buffer` is set to point to `devpriv->name`, which makes sense, given the intention to use it as a string buffer. It also sets up `s.size` to the size of `devpriv->name`, and initializes `s.len` and `s.readpos` to zero. That sets up the buffer, its capacity, and the current status. But the part I need to grok here is `seq_buf_str(&s)`. I remember reading the seq files documentation, but just to be sure, it looks like I need to dive into the definition of `seq_buf_str` to truly understand what's happening.

70/3

2026/09/15 11:13

tool

grepper

Args:

{
  "Expression": "seq_buf_str",
  "PathPrefix": "include/linux/seq_buf.h"
}

Results:

{
  "Output": "include/linux/seq_buf.h=77=static inline unsigned int seq_buf_used(struct seq_buf *s)\n--\ninclude/linux/seq_buf.h-82-/**\ninclude/linux/seq_buf.h:83: * seq_buf_str - get NUL-terminated C string from seq_buf\ninclude/linux/seq_buf.h-84- * @s: the seq_buf handle\n--\ninclude/linux/seq_buf.h-97- */\ninclude/linux/seq_buf.h:98:static inline const char *seq_buf_str(struct seq_buf *s)\ninclude/linux/seq_buf.h-99-{\n"
}

71/3

2026/09/15 11:13

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 22369
							output: 36
							thoughts: 24

Thoughts:

Here's a first-person summary, tailored as requested:

**Diving into `seq_buf.h`'s Core**

Okay, time to get my hands dirty. Let's pull up `include/linux/seq_buf.h` and focus in on lines 80 through 120. I need to refresh my memory on how this buffer is handled within the kernel and its critical characteristics. I'm going to have to carefully consider it; I need to remember the intricacies of its design. It's used for efficient, sequential writes to a character buffer, right? I need to think about how this affects the user space. Does this mean it's primarily designed for fast logging or trace information, where sequential access is the norm? Is the design optimal or are there things I could see that I would change if I were working on a system where this was a bottleneck?

I'm particularly interested in memory management nuances. What's the allocation strategy? Is it a statically sized buffer, or does it grow dynamically? If dynamic, what's the growth mechanism, and how does that impact performance and fragmentation over time? I want to see if the implementation handles potential race conditions, concurrent access, or interrupt contexts correctly. This is important to ensure data integrity and avoid any potential kernel panics.

My goal here is to analyze the trade-offs the developers made; does it prioritize speed, memory usage, or something else entirely? Also, are there opportunities for optimization? Let's get to it.

72/3

2026/09/15 11:13

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 80,
  "LineCount": 40
}

Results:

{
  "Contents": "  80:\t}\n  81:\t\n  82:\t/**\n  83:\t * seq_buf_str - get NUL-terminated C string from seq_buf\n  84:\t * @s: the seq_buf handle\n  85:\t *\n  86:\t * This makes sure that the buffer in @s is NUL-terminated and\n  87:\t * safe to read as a string.\n  88:\t *\n  89:\t * Note, if this is called when the buffer has overflowed, then\n  90:\t * the last byte of the buffer is zeroed, and the len will still\n  91:\t * point passed it.\n  92:\t *\n  93:\t * After this function is called, s-\u003ebuffer is safe to use\n  94:\t * in string operations.\n  95:\t *\n  96:\t * Returns: @s-\u003ebuf after making sure it is terminated.\n  97:\t */\n  98:\tstatic inline const char *seq_buf_str(struct seq_buf *s)\n  99:\t{\n 100:\t\tif (WARN_ON(s-\u003esize == 0))\n 101:\t\t\treturn \"\";\n 102:\t\n 103:\t\tif (seq_buf_buffer_left(s))\n 104:\t\t\ts-\u003ebuffer[s-\u003elen] = 0;\n 105:\t\telse\n 106:\t\t\ts-\u003ebuffer[s-\u003esize - 1] = 0;\n 107:\t\n 108:\t\treturn s-\u003ebuffer;\n 109:\t}\n 110:\t\n 111:\t/**\n 112:\t * seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t *\n 116:\t * Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t */\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)\n"
}

73/3

2026/09/15 11:13

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 23316
							output: 34
							thoughts: 408

Thoughts:

**My Line of Reasoning**

Okay, so `seq_buf_str` is responsible for null-terminating the buffer. Wait a minute... didn't I see something earlier that initialized the string as empty? Ah, yes, `devpriv->name[0] = 0;`. That seems redundant, doesn't it? If the loop doesn't execute, or if `seq_buf_str(&s)` is called at the end without printing anything, what's actually in `devpriv->name`?

Let me think this through: `seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));` sets `s.len` to zero at the beginning. Then, if nothing is printed to the buffer, `seq_buf_str(&s)` does indeed set `s->buffer[0] = 0`, so `devpriv->name[0] = 0`. It *is* null-terminated. And, since `devpriv` was `kzalloc`'d, it should already be zeroed. Good, it's consistent.

Just to be thorough, I should look at related code. Let's see... what about the other files?

Right, `drivers/edac/thunderx_edac.c`:

```c
static void decode_register(char *str, size_t size,
...
+	if (size > 0)
+		str[0] = '\0';
```
That's pretty explicit: if the size is greater than zero, then `str[0] = '\0'`, setting the first character to null which also initializes the string to be empty.

And then I see:

```c
-		snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx",
-			ocx->edac_dev->ctl_name, ctx->reg_com_int);
+		seq_buf_init(&s, msg, OCX_MESSAGE_SIZE);
+
+		seq_buf_printf(&s, "%s: OCX_COM_INT: %016llx",
+			       ocx->edac_dev->ctl_name, ctx->reg_com_int);
```
Here, they're using `seq_buf` rather than `snprintf`. I'll quickly double-check where `msg` is defined. Is it a stack buffer or an array? Let's check `drivers/edac/thunderx_edac.c`.

74/3

2026/09/15 11:13

tool

grepper

Error:

no matches

Args:

{
  "Expression": "msg\\[",
  "PathPrefix": "drivers/edac/thunderx_edac.c"
}

Results:

{
  "error": "no matches"
}

75/3

2026/09/15 11:13

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 24332
							output: 41
							thoughts: 26

Thoughts:

Here's a summary of my thought process, as if I were the one thinking it:

**Diving into ThunderX EDAC**

Okay, time to get to the heart of the matter. I need to zero in on the EDAC driver for the ThunderX platform. The specific area I'm focusing on right now is around line 1115 in `drivers/edac/thunderx_edac.c`. I have a feeling something interesting, or potentially problematic, is going on in that section of the code. Let's see what the context is. I'll take a close look at the surrounding lines to understand the logic flow and identify the key functions or data structures being used. Hopefully, this will lead me to the root cause, or at least a clearer understanding of the issue I'm investigating. I need to quickly recall the expected behavior of the ThunderX EDAC controller and how it's supposed to handle ECC errors. Let's see what secrets this section of code is hiding.

76/3

2026/09/15 11:13

tool

read-file

Args:

{
  "File": "drivers/edac/thunderx_edac.c",
  "FirstLine": 1110,
  "LineCount": 40
}

Results:

{
  "Contents": "1110:\t\tunsigned long tail;\n1111:\t\tstruct ocx_com_err_ctx *ctx;\n1112:\t\tint lane;\n1113:\t\tchar *msg;\n1114:\t\tchar *other;\n1115:\t\n1116:\t\tmsg = kmalloc(OCX_MESSAGE_SIZE, GFP_KERNEL);\n1117:\t\tother = kmalloc(OCX_OTHER_SIZE, GFP_KERNEL);\n1118:\t\n1119:\t\tif (!msg || !other)\n1120:\t\t\tgoto err_free;\n1121:\t\n1122:\t\twhile (CIRC_CNT(ocx-\u003ecom_ring_head, ocx-\u003ecom_ring_tail,\n1123:\t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx))) {\n1124:\t\t\tstruct seq_buf s;\n1125:\t\n1126:\t\t\ttail = ring_pos(ocx-\u003ecom_ring_tail,\n1127:\t\t\t\t\tARRAY_SIZE(ocx-\u003ecom_err_ctx));\n1128:\t\t\tctx = \u0026ocx-\u003ecom_err_ctx[tail];\n1129:\t\n1130:\t\t\tseq_buf_init(\u0026s, msg, OCX_MESSAGE_SIZE);\n1131:\t\n1132:\t\t\tseq_buf_printf(\u0026s, \"%s: OCX_COM_INT: %016llx\",\n1133:\t\t\t\t       ocx-\u003eedac_dev-\u003ectl_name, ctx-\u003ereg_com_int);\n1134:\t\n1135:\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n1136:\t\t\t\t\tocx_com_errors, ctx-\u003ereg_com_int);\n1137:\t\n1138:\t\t\tseq_buf_puts(\u0026s, other);\n1139:\t\n1140:\t\t\tfor (lane = 0; lane \u003c OCX_RX_LANES; lane++)\n1141:\t\t\t\tif (ctx-\u003ereg_com_int \u0026 BIT(lane)) {\n1142:\t\t\t\t\tseq_buf_printf(\u0026s,\n1143:\t\t\t\t\t\t       \"\\n\\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx\",\n1144:\t\t\t\t\t\t       lane, ctx-\u003ereg_lane_int[lane],\n1145:\t\t\t\t\t\t       lane, ctx-\u003ereg_lane_stat11[lane]);\n1146:\t\n1147:\t\t\t\t\tdecode_register(other, OCX_OTHER_SIZE,\n1148:\t\t\t\t\t\t\tocx_lane_errors,\n1149:\t\t\t\t\t\t\tctx-\u003ereg_lane_int[lane]);\n"
}

77/3

2026/09/15 11:13

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 25307
							output: 34
							thoughts: 1902

Thoughts:

**Code Review: A Deep Dive into Memory Safety and String Handling**

Okay, let's break this down. First, the initial change to `decode_register` caught my eye. The addition of `str[0] = '\0'` at the beginning, conditional on `size > 0`, immediately flags a potential issue. Before, if `decode_register` didn't write anything, `other` would have contained garbage, leading to a read of uninitialized memory by `strlcat`. The patch is *clearly* fixing a vulnerability here by ensuring a null terminator, making `other` a valid empty string even when no description matches are found. Good catch.

Moving on, the `drm_dp_mst_topology.c` change seems straightforward. Replacing `snprintf` and `strlcat` with the `seq_buf` API is a standard approach to avoid buffer overflows. The use of `seq_buf_str` to guarantee null-termination at the end gives me peace of mind here. It seems the goal here is to construct a path string, and this is a much safer, cleaner way to do it, and avoids any potential overflow by checking the capacity of the buffer.

Now, we get to the juicy part – `xe_gt_sriov_pf_debugfs.c`. This is where it gets interesting. `engines` is a *stack* buffer. That's my first red flag. The code then initializes a `seq_buf` on this stack buffer *without* initializing the buffer itself. This is a problem! The critical question is, "What happens if `group >= num_groups`?". If the condition is false, the code jumps directly to `seq_buf_str(&s)`. `seq_buf_str` itself checks for the edge case, which is a good thing, and sets the first byte to `0` if it's the beginning of the string, which it would be. That ensures an empty string is returned, preventing any uninitialized reads during the `simple_read_from_buffer` call.

The more significant potential issue is the scenario if `group < num_groups`. The loop potentially writes to the `seq_buf`, but `seq_buf_printf` and `seq_buf_puts` are crucial here. I need to dive deeper into those to ensure they handle potential overflows correctly. The code calls `s_str = seq_buf_str(&s)` which returns a pointer to the now-populated buffer and copies `strlen(s_str)` bytes to the user. I need to make sure the loop never writes past the end of the buffer, or the `simple_read_from_buffer` will have a bad time. Then, `seq_buf_str` can potentially truncate the buffer (sets the null terminator at `s->size -1` if `seq_buf_buffer_left` returns false) and ensures the string can be read from userspace. My assumption is that the `seq_buf` implementation handles overflows gracefully by potentially truncating the buffer, which would prevent writing past the end of it.

Overall, the initial change fixes a definite memory safety issue. The second is safe and clean, and is exactly what I would recommend. The last needs a little more digging, but it *seems* safe because of the null termination and buffer management provided by `seq_buf`. I'd still want to confirm the overflow handling within `seq_buf_printf`, and `seq_buf_puts` to be absolutely certain, but on the surface, this looks good.

78/3

2026/09/15 11:14

tool

grepper

Args:

{
  "Expression": "seq_buf_puts",
  "PathPrefix": "include/linux/seq_buf.h"
}

Results:

{
  "Output": "include/linux/seq_buf.h=174=extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,\ninclude/linux/seq_buf.h-175-\t\t\t   size_t start, int cnt);\ninclude/linux/seq_buf.h:176:extern int seq_buf_puts(struct seq_buf *s, const char *str);\ninclude/linux/seq_buf.h-177-extern int seq_buf_putc(struct seq_buf *s, unsigned char c);\n"
}

79/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 28150
							output: 32
							thoughts: 35

Thoughts:

Okay, here's my take on those thoughts, tailored for an expert audience:

**Diving into `lib/seq_buf.c` for Buffer Write Mechanics**

Right, let's get down to brass tacks. I need to refresh my understanding of how the `seq_buf` library handles output. I'm specifically interested in the low-level details of writing to the buffers. That means I'm going to jump into `lib/seq_buf.c`. My primary targets are the `seq_buf_printf` and `seq_buf_puts` functions. I want to see precisely how they manage the buffer writes. Are they doing direct memory access? Are there internal locks? How does error handling work in a write failure? Understanding these mechanics is crucial to grasp how the entire `seq_buf` system functions and to identify potential bottlenecks or subtle bugs down the line, especially in high-concurrency or resource-constrained scenarios. Time to see what the implementation details reveal.

80/3

2026/09/15 11:14

tool

grepper

Args:

{
  "Expression": "seq_buf_puts",
  "PathPrefix": "lib/seq_buf.c"
}

Results:

{
  "Output": "lib/seq_buf.c=154=int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)\n--\nlib/seq_buf.c-173-/**\nlib/seq_buf.c:174: * seq_buf_puts - sequence printing of simple string\nlib/seq_buf.c-175- * @s: seq_buf descriptor\n--\nlib/seq_buf.c-181- */\nlib/seq_buf.c:182:int seq_buf_puts(struct seq_buf *s, const char *str)\nlib/seq_buf.c-183-{\n--\nlib/seq_buf.c-199-}\nlib/seq_buf.c:200:EXPORT_SYMBOL_GPL(seq_buf_puts);\nlib/seq_buf.c-201-\n"
}

81/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 28655
							output: 35
							thoughts: 21

Thoughts:

Okay, let's dive into this. I'm going to pull up lines 182 through 205 of `lib/seq_buf.c`. I need to get a clear picture of what's happening within that specific segment. My focus is probably going to be around the functions or data structures defined in this area, depending on my current task or what I'm looking to optimize. I'll be looking for potential memory management issues, concurrency implications, or simply the overall flow of data within this buffer. I expect it contains some essential part to the buffer management code. Let's see what's what.

82/3

2026/09/15 11:14

tool

read-file

Args:

{
  "File": "lib/seq_buf.c",
  "FirstLine": 180,
  "LineCount": 30
}

Results:

{
  "Contents": " 180:\t * Returns: zero on success, -1 on overflow.\n 181:\t */\n 182:\tint seq_buf_puts(struct seq_buf *s, const char *str)\n 183:\t{\n 184:\t\tsize_t len = strlen(str);\n 185:\t\n 186:\t\tWARN_ON(s-\u003esize == 0);\n 187:\t\n 188:\t\t/* Add 1 to len for the trailing null byte which must be there */\n 189:\t\tlen += 1;\n 190:\t\n 191:\t\tif (seq_buf_can_fit(s, len)) {\n 192:\t\t\tmemcpy(s-\u003ebuffer + s-\u003elen, str, len);\n 193:\t\t\t/* Don't count the trailing null byte against the capacity */\n 194:\t\t\ts-\u003elen += len - 1;\n 195:\t\t\treturn 0;\n 196:\t\t}\n 197:\t\tseq_buf_set_overflow(s);\n 198:\t\treturn -1;\n 199:\t}\n 200:\tEXPORT_SYMBOL_GPL(seq_buf_puts);\n 201:\t\n 202:\t/**\n 203:\t * seq_buf_putc - sequence printing of simple character\n 204:\t * @s: seq_buf descriptor\n 205:\t * @c: simple character to record\n 206:\t *\n 207:\t * Copy a single character into the sequence buffer.\n 208:\t *\n 209:\t * Returns: zero on success, -1 on overflow.\n"
}

83/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 29280
							output: 32
							thoughts: 72

Thoughts:

Okay, let's break this down.

**Investigating `seq_buf_puts` and its Potential Implications for `seq_buf_printf`**

Right, so `seq_buf_puts` is moving data, specifically a length of `len` bytes including the null terminator, into the buffer. Critically, it then increments `s->len` by `len - 1`. That makes sense: you copy the full string including the null, and `s->len` then points to the end of the *data* portion, not past the null. I have to keep that null-termination in mind, always.

But now I'm wondering about the implications for `seq_buf_printf`.  Since I'm building strings, `printf`-like operations are key, and I'd bet the buffer is being built up for other reasons. I need to understand how *that* function handles things. It's obviously going to be more complex than a straight memory copy. I'll need to check the code for `seq_buf_printf`, and the best place for it is in `lib/seq_buf.c`.

84/3

2026/09/15 11:14

tool

grepper

Args:

{
  "Expression": "seq_buf_printf",
  "PathPrefix": "lib/seq_buf.c"
}

Results:

{
  "Output": "lib/seq_buf.c=67=int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)\n--\nlib/seq_buf.c-84-/**\nlib/seq_buf.c:85: * seq_buf_printf - sequence printing of information\nlib/seq_buf.c-86- * @s: seq_buf descriptor\n--\nlib/seq_buf.c-92- */\nlib/seq_buf.c:93:int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)\nlib/seq_buf.c-94-{\n--\nlib/seq_buf.c-103-}\nlib/seq_buf.c:104:EXPORT_SYMBOL_GPL(seq_buf_printf);\nlib/seq_buf.c-105-\n--\nlib/seq_buf.c=403=int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, int prefix_type,\n--\nlib/seq_buf.c-423-\t\tcase DUMP_PREFIX_ADDRESS:\nlib/seq_buf.c:424:\t\t\tret = seq_buf_printf(s, \"%s%p: %s\\n\",\nlib/seq_buf.c-425-\t\t\t       prefix_str, ptr + i, linebuf);\n--\nlib/seq_buf.c-427-\t\tcase DUMP_PREFIX_OFFSET:\nlib/seq_buf.c:428:\t\t\tret = seq_buf_printf(s, \"%s%.8x: %s\\n\",\nlib/seq_buf.c-429-\t\t\t\t\t     prefix_str, i, linebuf);\n--\nlib/seq_buf.c-431-\t\tdefault:\nlib/seq_buf.c:432:\t\t\tret = seq_buf_printf(s, \"%s%s\\n\", prefix_str, linebuf);\nlib/seq_buf.c-433-\t\t\tbreak;\n"
}

85/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 30128
							output: 34
							thoughts: 22

Thoughts:

Here's my take on those lines of `lib/seq_buf.c`:

**Analyzing `lib/seq_buf.c` - Lines 67-104**

Alright, let's dive into those lines in `lib/seq_buf.c` – 67 through 104, specifically. I want to see what's happening within that segment of code. It looks like we're likely dealing with the core buffering logic, given the file name. Based on the surrounding code, I'd expect to see operations related to either reading from or writing to the sequence buffer. This could be where we manage the circular buffer itself, track read/write pointers, or handle overflow conditions.

My initial hypothesis is that this section contains a critical function, possibly a read or write method. I suspect we'll be dealing with pointer arithmetic, boundary checks, and potentially some form of locking to ensure thread safety. If this section involves writing, I anticipate seeing logic that handles filling the buffer, wrapping around to the beginning, and managing the `seq_buf`'s internal state. Conversely, if it's a read operation, I'm expecting to see logic that fetches data from the buffer, updates the read pointer, and deals with potential underflow conditions, i.e., trying to read past what's written. Given the context of a sequence buffer, which is likely used for streaming or sequential data access, memory management might also come into play here. We'll have to see how memory is allocated, deallocated, or managed dynamically. I'm keen to spot any performance optimizations, such as using prefetching, unrolling loops, or techniques to minimize memory accesses.

86/3

2026/09/15 11:14

tool

read-file

Args:

{
  "File": "lib/seq_buf.c",
  "FirstLine": 67,
  "LineCount": 40
}

Results:

{
  "Contents": "  67:\tint seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)\n  68:\t{\n  69:\t\tint len;\n  70:\t\n  71:\t\tWARN_ON(s-\u003esize == 0);\n  72:\t\n  73:\t\tif (s-\u003elen \u003c s-\u003esize) {\n  74:\t\t\tlen = vsnprintf(s-\u003ebuffer + s-\u003elen, s-\u003esize - s-\u003elen, fmt, args);\n  75:\t\t\tif (s-\u003elen + len \u003c s-\u003esize) {\n  76:\t\t\t\ts-\u003elen += len;\n  77:\t\t\t\treturn 0;\n  78:\t\t\t}\n  79:\t\t}\n  80:\t\tseq_buf_set_overflow(s);\n  81:\t\treturn -1;\n  82:\t}\n  83:\t\n  84:\t/**\n  85:\t * seq_buf_printf - sequence printing of information\n  86:\t * @s: seq_buf descriptor\n  87:\t * @fmt: printf format string\n  88:\t *\n  89:\t * Writes a printf() format into the sequence buffer.\n  90:\t *\n  91:\t * Returns: zero on success, -1 on overflow.\n  92:\t */\n  93:\tint seq_buf_printf(struct seq_buf *s, const char *fmt, ...)\n  94:\t{\n  95:\t\tva_list ap;\n  96:\t\tint ret;\n  97:\t\n  98:\t\tva_start(ap, fmt);\n  99:\t\tret = seq_buf_vprintf(s, fmt, ap);\n 100:\t\tva_end(ap);\n 101:\t\n 102:\t\treturn ret;\n 103:\t}\n 104:\tEXPORT_SYMBOL_GPL(seq_buf_printf);\n 105:\t\n 106:\t/**\n"
}

87/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 31046
							output: 34
							thoughts: 464

Thoughts:

**Analyzing a Potential Buffer Overflow**

Okay, so I'm digging into this code and I've got a potential vulnerability to consider. `vsnprintf` is the key here; it writes into the buffer `s->buffer + s->len` and critically, *always* null-terminates the string it writes. That's good. But I need to verify that null-termination behavior with `seq_buf_str`.

I'm checking this `seq_buf_str` function and it's interesting. It looks like it handles two cases. If there's space left in the buffer, it null-terminates at `s->buffer[s->len]`. But, if the buffer *did* overflow, it null-terminates at `s->buffer[s->size - 1]`.

Now, I've got to look at this `control_read` function in `xe_gt_sriov_pf_debugfs.c`. I see it uses a `seq_buf` to build a string of commands, with `seq_buf_printf` being used in a loop. I'm focusing on the call to `simple_read_from_buffer`.

And hold on... **WAIT!** I just spotted something that's making me double-take! I see `simple_read_from_buffer(buf, count, ppos, help, seq_buf_used(&s));` and I need to know precisely what `seq_buf_used(&s)` is returning. I need to understand if `seq_buf_used` is taking into account the null-termination behavior of `seq_buf_str`. It's crucial here, because `simple_read_from_buffer` is going to read that much data. This is where a potential overflow could arise. I need to verify what `seq_buf_used` actually *does*.

88/3

2026/09/15 11:14

tool

grepper

Args:

{
  "Expression": "seq_buf_used",
  "PathPrefix": "include/linux/seq_buf.h"
}

Results:

{
  "Output": "include/linux/seq_buf.h=68=seq_buf_buffer_left(struct seq_buf *s)\n--\ninclude/linux/seq_buf.h-76-/* How much buffer was written? */\ninclude/linux/seq_buf.h:77:static inline unsigned int seq_buf_used(struct seq_buf *s)\ninclude/linux/seq_buf.h-78-{\n"
}

89/3

2026/09/15 11:14

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 32059
							output: 36
							thoughts: 23

Thoughts:

Here's my attempt at summarizing the thought process, as if I were a Linux kernel expert:

**Diving into `seq_buf.h` - Lines 65-82**

Okay, time to get my hands dirty. I'm zeroing in on lines 65-82 of `include/linux/seq_buf.h`. This is where the core of the `seq_buf` implementation is, likely handling either allocation, resizing, or perhaps the actual data write process. Let's see... I bet there's some kind of structure definition in that range, probably something like `struct seq_buf` itself, or maybe a helper struct used internally. I'm expecting to see members for the buffer's current size, its allocated size, a pointer to the actual data, and maybe some flags for management. I'm also betting we'll see some inline functions or macros. I'm really curious to see how they handle potential overflows and memory management within the buffer. I am curious to see if they're taking a page-based approach, or a contiguous buffer approach, and how they implement that. Alright, let's take a look.

90/3

2026/09/15 11:15

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 65,
  "LineCount": 20
}

Results:

{
  "Contents": "  65:\t * How much buffer is left on the seq_buf?\n  66:\t */\n  67:\tstatic inline unsigned int\n  68:\tseq_buf_buffer_left(struct seq_buf *s)\n  69:\t{\n  70:\t\tif (seq_buf_has_overflowed(s))\n  71:\t\t\treturn 0;\n  72:\t\n  73:\t\treturn s-\u003esize - s-\u003elen;\n  74:\t}\n  75:\t\n  76:\t/* How much buffer was written? */\n  77:\tstatic inline unsigned int seq_buf_used(struct seq_buf *s)\n  78:\t{\n  79:\t\treturn min(s-\u003elen, s-\u003esize);\n  80:\t}\n  81:\t\n  82:\t/**\n  83:\t * seq_buf_str - get NUL-terminated C string from seq_buf\n  84:\t * @s: the seq_buf handle\n"
}

91/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 32627
							output: 36
							thoughts: 152

Thoughts:

**Analyzing `seq_buf_printf` Overflow Behavior**

Okay, hold on a second. I'm looking at how `seq_buf_printf` handles potential overflows, and there's a specific section I want to dig into. It's this block of code:

```c
	if (s->len < s->size) {
		len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
		if (s->len + len < s->size) {
			s->len += len;
			return 0;
		}
	}
	seq_buf_set_overflow(s);
	return -1;
```

Interesting. It looks like it tries to use `vsnprintf` within the allocated buffer. If there's enough space, it updates the length and returns zero, indicating success. But there's this `seq_buf_set_overflow(s)` call in the `else` block, followed by returning `-1`. What exactly is `seq_buf_set_overflow` doing? I need to understand that function call to have a complete picture of the overflow handling. Time to jump over to the header file, `include/linux/seq_buf.h`, and see what's defined there.

92/3

2026/09/15 11:15

tool

grepper

Args:

{
  "Expression": "seq_buf_set_overflow",
  "PathPrefix": "include/linux/seq_buf.h"
}

Results:

{
  "Output": "include/linux/seq_buf.h=58=static inline void\ninclude/linux/seq_buf.h:59:seq_buf_set_overflow(struct seq_buf *s)\ninclude/linux/seq_buf.h-60-{\n--\ninclude/linux/seq_buf.h=141=static inline void seq_buf_commit(struct seq_buf *s, int num)\n--\ninclude/linux/seq_buf.h-143-\tif (num \u003c 0) {\ninclude/linux/seq_buf.h:144:\t\tseq_buf_set_overflow(s);\ninclude/linux/seq_buf.h-145-\t} else {\n"
}

93/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 33279
							output: 36
							thoughts: 23

Thoughts:

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Diving into `seq_buf.h`**

Okay, time to get my hands dirty and look at the implementation details, specifically focusing on lines 50-65 of `include/linux/seq_buf.h`. I need to refresh my understanding of how this particular buffering mechanism is implemented. I'm especially curious about the memory allocation strategy and any potential optimizations they've built into it. Are they using a ring buffer? Or perhaps dynamic resizing based on some threshold? Let's see if there are any subtle tricks to avoid unnecessary copying or alignment issues. I'll be looking for clues in the data structure definitions, any inline functions related to buffer manipulation, and error handling. I hope to get a handle on the complexity of this section. I want to identify any design decisions, tradeoffs made. Are they optimizing for speed? or memory usage? I am hoping this will give me some insight.

94/3

2026/09/15 11:15

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 50,
  "LineCount": 20
}

Results:

{
  "Contents": "  50:\t * len is set to be greater than size.\n  51:\t */\n  52:\tstatic inline bool\n  53:\tseq_buf_has_overflowed(struct seq_buf *s)\n  54:\t{\n  55:\t\treturn s-\u003elen \u003e s-\u003esize;\n  56:\t}\n  57:\t\n  58:\tstatic inline void\n  59:\tseq_buf_set_overflow(struct seq_buf *s)\n  60:\t{\n  61:\t\ts-\u003elen = s-\u003esize + 1;\n  62:\t}\n  63:\t\n  64:\t/*\n  65:\t * How much buffer is left on the seq_buf?\n  66:\t */\n  67:\tstatic inline unsigned int\n  68:\tseq_buf_buffer_left(struct seq_buf *s)\n  69:\t{\n"
}

95/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 33785
							output: 45
							thoughts: 222

Thoughts:

**Analyzing the `control_read` Function**

Okay, hold on a second. I need to take a closer look at this `control_read` function. Specifically, I need to understand what it's *really* doing. The code snippet looks straightforward enough: it seems to be reading something into a buffer and then writing it out. But what exactly *is* being read?

The function uses `seq_buf` and `simple_read_from_buffer`, which are common enough. It looks like it constructs a string with newline delimiters. The loop iterates through `control_cmds`. The crucial piece is `control_cmds`. What exactly *is* in `control_cmds`? And how many entries are there? That’s the key. I need to know the structure and the size of `control_cmds` to truly grasp the function's purpose.

Let me go check `drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c`, that's where I assume I'll find its definition. Knowing the structure and content of `control_cmds` will clarify everything.

96/3

2026/09/15 11:15

tool

grepper

Args:

{
  "Expression": "control_cmds",
  "PathPrefix": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c"
}

Results:

{
  "Output": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=618=static const struct {\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-620-\tint (*fn)(struct xe_gt *gt, unsigned int vfid);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:621:} control_cmds[] = {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-622-\t{ \"stop\", xe_gt_sriov_pf_control_stop_vf },\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=627=static ssize_t control_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-651-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:652:\tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:653:\t\txe_gt_assert(gt, sizeof(cmd) \u003e strlen(control_cmds[n].cmd));\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-654-\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:655:\t\tif (sysfs_streq(cmd, control_cmds[n].cmd)) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-656-\t\t\tguard(xe_pm_runtime)(xe);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:657:\t\t\tret = control_cmds[n].fn ? (*control_cmds[n].fn)(gt, vfid) : 0;\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-658-\t\t\tbreak;\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c=665=static ssize_t control_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)\n--\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-671-\tseq_buf_init(\u0026s, help, sizeof(help));\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:672:\tfor (n = 0; n \u003c ARRAY_SIZE(control_cmds); n++) {\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c:673:\t\tseq_buf_printf(\u0026s, \"%s\\n\", control_cmds[n].cmd);\ndrivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c-674-\t}\n"
}

97/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 35098
							output: 50
							thoughts: 12

Thoughts:

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Analyzing the `control_cmds` Structure**

Okay, let's break this down. The first thing I'm doing is mentally dissecting the `control_cmds` object (or variable, depending on context). I'm not just glancing at it; I'm probing it, trying to determine its core structure. What are the key elements contained within it? Is it a list of dictionaries? A custom object with defined attributes? Does it use nested data structures? My initial approach is to mentally map out its composition. I'm looking for its fundamental building blocks and how they relate to each other. This is likely the crucial object that governs the commands or actions for the target process. I need to understand its form to understand its function. I'm focusing on the structural relationships first – the relationships and hierarchy between the commands. That should give me the foundation for the next stage.

98/3

2026/09/15 11:15

tool

read-file

Args:

{
  "File": "drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c",
  "FirstLine": 618,
  "LineCount": 15
}

Results:

{
  "Contents": " 618:\tstatic const struct {\n 619:\t\tconst char *cmd;\n 620:\t\tint (*fn)(struct xe_gt *gt, unsigned int vfid);\n 621:\t} control_cmds[] = {\n 622:\t\t{ \"stop\", xe_gt_sriov_pf_control_stop_vf },\n 623:\t\t{ \"pause\", xe_gt_sriov_pf_control_pause_vf },\n 624:\t\t{ \"resume\", xe_gt_sriov_pf_control_resume_vf },\n 625:\t};\n 626:\t\n 627:\tstatic ssize_t control_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)\n 628:\t{\n 629:\t\tstruct dentry *dent = file_dentry(file);\n 630:\t\tstruct dentry *parent = dent-\u003ed_parent;\n 631:\t\tstruct xe_gt *gt = extract_gt(parent);\n 632:\t\tstruct xe_device *xe = gt_to_xe(gt);\n"
}

99/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 35659
							output: 32
							thoughts: 293

Thoughts:

**Analyzing String Handling**

Okay, so I'm looking at this `control_cmds` thing and it's just three static strings, "stop", "pause", and "resume". That's tiny – probably around 20 bytes total. Definitely less than the 128 bytes I was initially considering.

Hang on a second… I need to check something in the `synaptics_usb.c` driver, specifically, how they handle string construction with `usb_make_path`. This is interesting; I need to understand what's happening there to make sure my approach is optimized. I'm focusing on the buffer sizes and string operations now. Let's see what `usb_make_path` actually does.

100/3

2026/09/15 11:15

tool

grepper

Error:

no matches

Args:

{
  "Expression": "int usb_make_path",
  "PathPrefix": "drivers/usb/core/"
}

Results:

{
  "error": "no matches"
}

101/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 36154
							output: 30
							thoughts: 13

Thoughts:

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Investigating `usb_make_path`**

Alright, let's dive in. My immediate thought is to locate the definition of `usb_make_path`. This usually means I'm trying to understand how a USB device's path is constructed within the system. Is it a function, a macro, a data structure... and where is it declared? My understanding is a critical first step if I want to debug the USB subsystem. I'll need to know whether I'm looking for the code itself, to see what variables it acts on, or whether I'm looking for a data structure containing a path for a particular USB device. Perhaps I am looking to modify a particular structure to achieve a particular result. Knowing this will give context to how a USB path is created, and this in turn tells me what the system's "understanding" is. This is the starting point for any deeper analysis or modification I might need to make in this area. From here, I can examine its implementation, any related structures, and the calling contexts to build a complete picture.

102/3

2026/09/15 11:15

tool

grepper

Args:

{
  "Expression": "usb_make_path\\(",
  "PathPrefix": "drivers/usb/"
}

Results:

{
  "Output": "drivers/usb/atm/usbatm.c=1008=int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,\n--\ndrivers/usb/atm/usbatm.c-1048-\ndrivers/usb/atm/usbatm.c:1049:\tif (length \u003c= 0 || (i = usb_make_path(usb_dev, buf, length)) \u003c 0)\ndrivers/usb/atm/usbatm.c-1050-\t\tgoto bind;\n--\ndrivers/usb/serial/usb-serial.c=543=static int serial_proc_show(struct seq_file *m, void *v)\n--\ndrivers/usb/serial/usb-serial.c-567-\t\tseq_printf(m, \" port:%d\", port-\u003eport_number);\ndrivers/usb/serial/usb-serial.c:568:\t\tusb_make_path(serial-\u003edev, tmp, sizeof(tmp));\ndrivers/usb/serial/usb-serial.c-569-\t\tseq_printf(m, \" path:%s\", tmp);\n--\ndrivers/usb/storage/onetouch.c=163=static int onetouch_connect_input(struct us_data *ss)\n--\ndrivers/usb/storage/onetouch.c-217-\ndrivers/usb/storage/onetouch.c:218:\tusb_make_path(udev, onetouch-\u003ephys, sizeof(onetouch-\u003ephys));\ndrivers/usb/storage/onetouch.c-219-\tstrlcat(onetouch-\u003ephys, \"/input0\", sizeof(onetouch-\u003ephys));\n"
}

103/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 36852
							output: 21
							thoughts: 14

Thoughts:

Here's a summary of my thought process, as if I were the one thinking it:

**Finding the `usb_make_path` Definition**

Okay, so I need to find the definition of `usb_make_path`. That's the starting point. It's likely a function, given the naming convention, and it's probably related to USB device paths, which is intriguing. I'm going to start by searching my project's codebase, and if that fails, I'll go digging through the kernel source documentation or the relevant USB subsystem header files. I'll be looking for where this function is declared, and importantly, how it's used. Understanding its context will be key. Is it part of the core USB stack, or a more specialized driver? Knowing its location will help me understand its significance in the bigger picture. From the definition, I will infer its inputs, outputs, and purpose.

104/3

2026/09/15 11:15

tool

grepper

Args:

{
  "Expression": "int usb_make_path\\("
}

Results:

{
  "Output": "include/linux/usb.h=954=int usb_hub_release_port(struct usb_device *hdev, unsigned port1,\n--\ninclude/linux/usb.h-981- */\ninclude/linux/usb.h:982:static inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)\ninclude/linux/usb.h-983-{\n"
}

105/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 37194
							output: 35
							thoughts: 20

Thoughts:

Here's a summary of my thought process, as requested:

**Diving into USB Core - Specifically, That Header File**

Okay, so I need to get a handle on how USB device management is handled at a low level in the Linux kernel. I'm going to start by examining `include/linux/usb.h`, aiming for around line 982. Hopefully, that will give me some insight into the core data structures and function declarations related to device handling. I'm hoping to understand how devices are probed, registered, and managed from a high-level perspective, and where the core implementations of that reside. Line 982 could be pivotal. It's time to start digging!

106/3

2026/09/15 11:15

tool

read-file

Args:

{
  "File": "include/linux/usb.h",
  "FirstLine": 980,
  "LineCount": 20
}

Results:

{
  "Contents": " 980:\t * high speed, and a different one if they are full or low speed.\n 981:\t */\n 982:\tstatic inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)\n 983:\t{\n 984:\t\tint actual;\n 985:\t\tactual = snprintf(buf, size, \"usb-%s-%s\", dev-\u003ebus-\u003ebus_name,\n 986:\t\t\t\t  dev-\u003edevpath);\n 987:\t\treturn (actual \u003e= (int)size) ? -1 : actual;\n 988:\t}\n 989:\t\n 990:\t/*-------------------------------------------------------------------------*/\n 991:\t\n 992:\t#define USB_DEVICE_ID_MATCH_DEVICE \\\n 993:\t\t\t(USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT)\n 994:\t#define USB_DEVICE_ID_MATCH_DEV_RANGE \\\n 995:\t\t\t(USB_DEVICE_ID_MATCH_DEV_LO | USB_DEVICE_ID_MATCH_DEV_HI)\n 996:\t#define USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION \\\n 997:\t\t\t(USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_DEV_RANGE)\n 998:\t#define USB_DEVICE_ID_MATCH_DEV_INFO \\\n 999:\t\t\t(USB_DEVICE_ID_MATCH_DEV_CLASS | \\\n"
}

107/3

2026/09/15 11:15

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 37788
							output: 37
							thoughts: 874

Thoughts:

**Analyzing USB Audio Card Naming in the Linux Kernel**

Okay, so I'm looking at this `usb_audio_make_longname` function, specifically in `sound/usb/card.c`. My initial thought was about how we're building this long name string, and I instinctively reached for `snprintf` because I'm used to ensuring null termination. But it seems like they're not using it directly. Instead, they're using this `seq_buf` structure, and it looks like it is intended to replace `snprintf`, and *does* handle null termination, but I'll have to verify that.

Now, I see the code using this `seq_buf` and it immediately sets up a buffer with `seq_buf_init`. It looks like it uses `seq_buf_puts` to append the vendor name, manufacturer, and short name. Then it appends " at " to the end, before calling a function `usb_make_path`.

The interesting part is `seq_buf_get_buf(&sb, &buf);`. The code then checks to make sure the returned `size` is > 0, indicating that it successfully retrieved a valid `buf` pointer and buffer `size`. If so, it calls `usb_make_path` to get the USB path, with the returned path length passed to `seq_buf_commit`.

I'm thinking, let's look closer at `seq_buf_get_buf`. I'll switch over to the header file `include/linux/seq_buf.h` to dive deeper. My assumption, based on how the code is structured, is that this must be the mechanism for getting the underlying buffer from the `seq_buf` structure. I'll check how it works and whether it handles null termination properly.

108/3

2026/09/15 11:16

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 110,
  "LineCount": 40
}

Results:

{
  "Contents": " 110:\t\n 111:\t/**\n 112:\t * seq_buf_get_buf - get buffer to write arbitrary data to\n 113:\t * @s: the seq_buf handle\n 114:\t * @bufp: the beginning of the buffer is stored here\n 115:\t *\n 116:\t * Returns: the number of bytes available in the buffer, or zero if\n 117:\t * there's no space.\n 118:\t */\n 119:\tstatic inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)\n 120:\t{\n 121:\t\tWARN_ON(s-\u003elen \u003e s-\u003esize + 1);\n 122:\t\n 123:\t\tif (s-\u003elen \u003c s-\u003esize) {\n 124:\t\t\t*bufp = s-\u003ebuffer + s-\u003elen;\n 125:\t\t\treturn s-\u003esize - s-\u003elen;\n 126:\t\t}\n 127:\t\n 128:\t\t*bufp = NULL;\n 129:\t\treturn 0;\n 130:\t}\n 131:\t\n 132:\t/**\n 133:\t * seq_buf_commit - commit data to the buffer\n 134:\t * @s: the seq_buf handle\n 135:\t * @num: the number of bytes to commit\n 136:\t *\n 137:\t * Commit @num bytes of data written to a buffer previously acquired\n 138:\t * by seq_buf_get_buf(). To signal an error condition, or that the data\n 139:\t * didn't fit in the available space, pass a negative @num value.\n 140:\t */\n 141:\tstatic inline void seq_buf_commit(struct seq_buf *s, int num)\n 142:\t{\n 143:\t\tif (num \u003c 0) {\n 144:\t\t\tseq_buf_set_overflow(s);\n 145:\t\t} else {\n 146:\t\t\t/* num must be negative on overflow */\n 147:\t\t\tBUG_ON(s-\u003elen + num \u003e s-\u003esize);\n 148:\t\t\ts-\u003elen += num;\n 149:\t\t}\n"
}

109/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 39682
							output: 27
							thoughts: 227

Thoughts:

**Analyzing the USB Path in `seq_buf_commit`**

Okay, let's break this down. I'm looking at `seq_buf_commit`, and the first thing that jumps out is `path_len = usb_make_path(dev, buf, size);`. Right, `path_len` is the result of `usb_make_path`. Now, what exactly does *that* function do? A quick look at its return value reveals an interesting condition: `return (actual >= (int)size) ? -1 : actual;`. So, if `actual` (the number of characters written) is less than `size`, it returns the actual number of characters written, excluding the null terminator. It's essentially telling us how many characters it successfully wrote to the buffer. And that buffer, `buf`, is `s->buffer + s->len`, meaning it's writing *into* an existing buffer, starting at a specific offset. Of course it will write the null terminator too.

Then we have `seq_buf_commit(&sb, path_len)`.  This is the crucial part. It's adding `path_len` to `sb.len`. If `path_len` is negative, we've got an overflow, and `seq_buf_set_overflow(&sb)` is called. Finally, before we're done, `seq_buf_str(&sb)` is invoked, which ensures that `card->longname` is properly null-terminated. Good practice.

My next question is, where is `card->longname` allocated? I need to understand where this memory is coming from. Time to dig into the `struct snd_card` definition in `include/sound/core.h` to see how that's handled.

110/3

2026/09/15 11:16

tool

grepper

Args:

{
  "Expression": "longname\\[",
  "PathPrefix": "include/sound/"
}

Results:

{
  "Output": "include/sound/core.h=101=struct snd_card {\n--\ninclude/sound/core.h-107-\tchar shortname[32];\t\t/* short name of this soundcard */\ninclude/sound/core.h:108:\tchar longname[80];\t\t/* name of this soundcard */\ninclude/sound/core.h-109-\tchar irq_descr[32];\t\t/* Interrupt description */\n"
}

111/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 40436
							output: 35
							thoughts: 480

Thoughts:

**Analyzing String Concatenation and Potential Buffer Overflows**

Okay, let's break this down. I see that `snd_card` is being allocated using `kzalloc` in `snd_card_new`. And I'm noticing that the `card->longname` is being initialized to zero. Interesting, and then `seq_buf_init` is called on that. But at the end `seq_buf_str` is called on the `card->longname`.  Okay, `card->longname` is `kzalloc`'ed which means its length should be known to be zero when `seq_buf_init` is called, and at the end of it's lifecycle, the `seq_buf_str` function is called.

Now, my mind immediately jumps to potential string vulnerabilities, so I'm diving into `include/linux/fortify-string.h` to see how `strcat` is handled.  Let's see...

Alright, here's `strcat`:  First, there's a check for `p_size == SIZE_MAX`. If so, it calls `__underlying_strcat(p, q)`.  Okay, probably not ideal. Otherwise, it calculates `p_len` using `__fortify_strlen(p)`. This is key. Then it uses `__builtin_snprintf` to append `q` to `p`, determining the `wanted` size. Finally, it checks if `p_size <= wanted`, and if so, it throws a `fortify_panic`.

Wait a minute, what if `p_len` is greater than or equal to `p_size`?  That means that the existing string `p` is *already* as long or longer than the allocated buffer!  In that scenario, `__builtin_snprintf` will write *past* the end, overwriting memory, and there's no check for that case.  That's a potential buffer overflow vulnerability right there, and a big problem!

So now the question is: what does `__fortify_strlen(p)` actually *do*? I'm going to have to check that function definition to understand its behavior in this context.

112/3

2026/09/15 11:16

tool

grepper

Args:

{
  "Expression": "__fortify_strlen",
  "PathPrefix": "include/linux/fortify-string.h"
}

Results:

{
  "Output": "include/linux/fortify-string.h=169=__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)\n--\ninclude/linux/fortify-string.h-208-\t__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),\t\\\ninclude/linux/fortify-string.h:209:\t\t__builtin_strlen(p), __fortify_strlen(p))\ninclude/linux/fortify-string.h-210-__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\ninclude/linux/fortify-string.h:211:__kernel_size_t __fortify_strlen(const char * const POS p)\ninclude/linux/fortify-string.h-212-{\n--\ninclude/linux/fortify-string.h=363=char *strcat(char * const POS p, const char *q)\n--\ninclude/linux/fortify-string.h-369-\ninclude/linux/fortify-string.h:370:\tconst size_t p_len = __fortify_strlen(p);\ninclude/linux/fortify-string.h-371-\tconst size_t wanted = p_len + __builtin_snprintf(p + p_len, p_size - p_len, \"%s\", q);\n"
}

113/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 41779
							output: 38
							thoughts: 26

Thoughts:

Here's my summary, as though I'm reading and processing the provided lines of code:

**Diving into `fortify-string.h`**

Okay, time to dig into the heart of the matter. Let's pull up lines 210-230 in `include/linux/fortify-string.h`. I'm expecting this section to deal with either direct buffer overflow protection or perhaps the enabling mechanisms around some of the compiler-based safety features. Given the file name, it's almost certainly related to string manipulation, which is a common source of vulnerabilities. I'm keen to see if it's using compile-time checks, runtime checks, or a combination of both. I'll be looking for macros or inline functions that are probably replacing standard C string functions, hopefully with added bounds checks or other safety features, likely utilizing the `__builtin_*` or similar compiler intrinsics to optimize the behavior. I’m hoping to gain insights into how the kernel mitigates string-related security risks, particularly with Fortify Source. I will also be considering if these are tied to any specific compiler flags or kernel configuration options. Let's see what’s there.

114/3

2026/09/15 11:16

tool

read-file

Args:

{
  "File": "include/linux/fortify-string.h",
  "FirstLine": 210,
  "LineCount": 25
}

Results:

{
  "Contents": " 210:\t__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)\n 211:\t__kernel_size_t __fortify_strlen(const char * const POS p)\n 212:\t{\n 213:\t\tconst size_t p_size = __member_size(p);\n 214:\t\t__kernel_size_t ret;\n 215:\t\n 216:\t\t/* Give up if we don't know how large p is. */\n 217:\t\tif (p_size == SIZE_MAX)\n 218:\t\t\treturn __underlying_strlen(p);\n 219:\t\tret = strnlen(p, p_size);\n 220:\t\tif (p_size \u003c= ret)\n 221:\t\t\tfortify_panic(FORTIFY_FUNC_strlen, FORTIFY_READ, p_size, ret + 1, ret);\n 222:\t\treturn ret;\n 223:\t}\n 224:\t\n 225:\t/* Defined after fortified strnlen() to reuse it. */\n 226:\textern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(sized_strscpy);\n 227:\t__FORTIFY_INLINE ssize_t sized_strscpy(char * const POS p, const char * const POS q, size_t size)\n 228:\t{\n 229:\t\t/* Use string size rather than possible enclosing struct size. */\n 230:\t\tconst size_t p_size = __member_size(p);\n 231:\t\tconst size_t q_size = __member_size(q);\n 232:\t\tsize_t len;\n 233:\t\n 234:\t\t/* If we cannot get size of p and q default to call strscpy. */\n"
}

115/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 42573
							output: 34
							thoughts: 515

Thoughts:

**Analyzing a Potential Vulnerability in `net/devlink/dev.c`**

Okay, so I'm thinking about this potential buffer overflow. The crucial point is how `__fortify_strlen` and related checks work in conjunction with `snprintf`. If `p_size` (the buffer size) is less than or equal to `ret` (the result of the prior `strlen`), then a panic occurs. This means `p_len` (the current length) must be less than `p_size`, and therefore `p_size - p_len` must be greater than zero. This guarantees that `snprintf(p + p_len, p_size - p_len, "%s", q)` is safe from simple overflow. However, it's possible that if the string `q` is sufficiently large, then the combined result of the `snprintf` would trigger a `p_size <= wanted` which in turn triggers `fortify_panic`. So, there's a potential risk of a crash there.

Now, let me shift my attention to `net/devlink/dev.c` where I see this code snippet:

```c
@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 {
 	struct devlink_info_req req = {};
 	const struct nlattr *nlattr;
+	struct seq_buf s;
 	struct sk_buff *msg;
 	int rem, err;

@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 	if (err)
 		goto free_msg;

+	seq_buf_init(&s, buf, len);
+	s.len = strnlen(buf, len);

 	nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,
 			       (void *)msg->data, msg->len, rem) {
 		const struct nlattr *kv;
@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 
 		nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,
 					 nlattr, rem_kv) {
-			strlcat(buf, nla_data(kv), len);
-			strlcat(buf, " ", len);
+			seq_buf_printf(&s, "%s ", (const char *)nla_data(kv));
 		}
 	}
 free_msg:
```

My initial thought is to scrutinize the calling context of `__devlink_compat_running_version` and determine what `buf` actually is, and the `len` passed. The code used to call `strlcat` on the buffer, but has been replaced with `seq_buf`. This is a welcome change. But I need to figure out the maximum size `buf` can reach to determine if there are potential overflow problems, or other errors. I need to consider what's happening *before* this code block and what happens with the `buf` after. I should also check the definition and usage of `struct seq_buf` very closely.

116/3

2026/09/15 11:16

tool

grepper

Args:

{
  "Expression": "__devlink_compat_running_version",
  "PathPrefix": "net/devlink/"
}

Results:

{
  "Output": "net/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t     char *buf, size_t len)\n--\nnet/devlink/dev.c=1224=void devlink_compat_running_version(struct devlink *devlink,\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n"
}

117/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 44137
							output: 22
							thoughts: 16

Thoughts:

Here's a breakdown of my thought process, as requested:

**Tracing Calls to `devlink_compat_running_version`**

Okay, so I need to understand where `devlink_compat_running_version` is being called within the system. That suggests I'm probably looking at compatibility checks or version management related to `devlink` devices. I'm likely interested in how different versions of `devlink` are handled or if there are version-specific features being used. This could be for a few reasons. Perhaps I am debugging some devlink compatibility issues or I am looking to trace some code that uses devlink version in some important functionality. Perhaps I am doing code reviews and I want to understand who uses this function.

I need to quickly locate all the call sites. Likely, I will use my tools to do this. I'll probably start with a `grep` or similar command to search the codebase for direct calls. I need to keep in mind that the name could be used in some indirect manner. If there is some macro or inline function that utilizes it, it is also important. So I must cast a wide net with my search. Once I've got that initial list, I can then dive into each call site to understand its context. From there, I'll need to see what each call is doing with the returned value, is it for logging, conditional checks, etc. This will help me build a complete picture of the role `devlink_compat_running_version` plays in the overall system.

118/3

2026/09/15 11:16

tool

grepper

Args:

{
  "Expression": "devlink_compat_running_version"
}

Results:

{
  "Output": "include/net/devlink.h=2121=void devlink_put(struct devlink *devlink);\ninclude/net/devlink.h-2122-\ninclude/net/devlink.h:2123:void devlink_compat_running_version(struct devlink *devlink,\ninclude/net/devlink.h-2124-\t\t\t\t    char *buf, size_t len);\n--\ninclude/net/devlink.h=2146=static inline void\ninclude/net/devlink.h:2147:devlink_compat_running_version(struct devlink *devlink, char *buf, size_t len)\ninclude/net/devlink.h-2148-{\n--\nnet/devlink/dev.c=1135=int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/devlink/dev.c-1188-\nnet/devlink/dev.c:1189:static void __devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1190-\t\t\t\t\t     char *buf, size_t len)\n--\nnet/devlink/dev.c-1223-\nnet/devlink/dev.c:1224:void devlink_compat_running_version(struct devlink *devlink,\nnet/devlink/dev.c-1225-\t\t\t\t    char *buf, size_t len)\n--\nnet/devlink/dev.c-1231-\tif (devl_is_registered(devlink))\nnet/devlink/dev.c:1232:\t\t__devlink_compat_running_version(devlink, buf, len);\nnet/devlink/dev.c-1233-\tdevl_unlock(devlink);\n--\nnet/ethtool/ioctl.c=3646=int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t       state-\u003einfo.fw_version,\n"
}

119/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 45095
							output: 38
							thoughts: 23

Thoughts:

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Diving into the Ethtool IOCTL Implementation**

Okay, time to get my hands dirty. I'm pretty sure the issue I'm chasing down is nestled somewhere within `net/ethtool/ioctl.c`, and I've got a hunch it's related to a particular IOCTL operation. Given the nature of the problem, I'm going to start my investigation right around line 3680. That location often deals with... [This is where you, the expert, would fill in the likely area of functionality. For example: "...handling specific features, configurations, or error conditions during the IOCTL calls. I anticipate it deals with the configuration of the network device."]. Let's see what the code around there reveals. I'll be looking for potential race conditions, incorrect parameter handling, or perhaps a subtle bug in the data structure manipulation. The goal is to quickly pinpoint the specific code path responsible for the erroneous behavior and understand the root cause. This is where I'll form a hypothesis and begin confirming it.

120/3

2026/09/15 11:16

tool

read-file

Args:

{
  "File": "net/ethtool/ioctl.c",
  "FirstLine": 3670,
  "LineCount": 25
}

Results:

{
  "Contents": "3670:\t\tif (rc)\n3671:\t\t\tgoto exit_free;\n3672:\t\n3673:\t\tswitch (ethcmd) {\n3674:\t\tcase ETHTOOL_FLASHDEV:\n3675:\t\t\tif (state-\u003edevlink)\n3676:\t\t\t\trc = devlink_compat_flash_update(state-\u003edevlink,\n3677:\t\t\t\t\t\t\t\t state-\u003eefl.data);\n3678:\t\t\tbreak;\n3679:\t\tcase ETHTOOL_GDRVINFO:\n3680:\t\t\tif (state-\u003edevlink)\n3681:\t\t\t\tdevlink_compat_running_version(state-\u003edevlink,\n3682:\t\t\t\t\t\t\t       state-\u003einfo.fw_version,\n3683:\t\t\t\t\t\t\t       sizeof(state-\u003einfo.fw_version));\n3684:\t\t\tif (copy_to_user(useraddr, \u0026state-\u003einfo, sizeof(state-\u003einfo))) {\n3685:\t\t\t\trc = -EFAULT;\n3686:\t\t\t\tgoto exit_free;\n3687:\t\t\t}\n3688:\t\t\tbreak;\n3689:\t\t}\n3690:\t\n3691:\texit_free:\n3692:\t\tif (state-\u003edevlink)\n3693:\t\t\tdevlink_put(state-\u003edevlink);\n3694:\t\tkfree(state);\n"
}

121/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 45750
							output: 34
							thoughts: 40

Thoughts:

Here's my take on the thought process, as if it were my own:

**ETHTOOL_GDRVINFO Investigation**

Alright, let's dive into this `ETHTOOL_GDRVINFO` situation. My immediate focus is on `state->info` – I need to understand what data it's holding and how it's being used within the context of the driver information retrieval. The critical piece of this puzzle is the `state` itself. Where is this structure allocated within the `dev_ethtool` function? I need to trace back the allocation and initialization of `state` to fully grasp its scope and purpose. Time to dig into the `dev_ethtool` code and follow the trail of `state`!

122/3

2026/09/15 11:16

tool

grepper

Args:

{
  "Expression": "devlink_compat_running_version",
  "PathPrefix": "net/ethtool/"
}

Results:

{
  "Output": "net/ethtool/ioctl.c=3646=int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)\n--\nnet/ethtool/ioctl.c-3680-\t\tif (state-\u003edevlink)\nnet/ethtool/ioctl.c:3681:\t\t\tdevlink_compat_running_version(state-\u003edevlink,\nnet/ethtool/ioctl.c-3682-\t\t\t\t\t\t       state-\u003einfo.fw_version,\n"
}

123/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 46120
							output: 38
							thoughts: 27

Thoughts:

Here's a summary of my thought process, as if I were the one reading this code:

**Diving into ethtool's ioctl Implementation**

Okay, time to dig into the `net/ethtool/ioctl.c` code again. Specifically, I'm focusing on lines 3640 through 3685. This range usually covers some critical functionality, and given the nature of ethtool's ioctls, it's likely dealing with either a fairly complex data structure interaction, or perhaps an important error condition handling. Given the line range, it is likely involved in the processing of some data from user space and applying it to the networking device, or the returning of results back to the user. I need to figure out what functionality this segment is responsible for, the data structures it manipulates, and any error paths it might take. Knowing the context of the surrounding code would be helpful. Understanding what ioctl command or commands are being handled here is critical for gaining a comprehensive view of the implementation and how it affects the kernel. Let's see... I'm expecting to potentially find calls to lower-level networking driver functions within this block, or some kind of validation logic. I'll need to pay close attention to potential race conditions, or access control violations, to make sure the code is safe and robust, especially considering user space interaction. Alright, let's get to it and read those lines carefully.

124/3

2026/09/15 11:16

tool

read-file

Args:

{
  "File": "net/ethtool/ioctl.c",
  "FirstLine": 3640,
  "LineCount": 45
}

Results:

{
  "Contents": "3640:\t\t\trtnl_unlock();\n3641:\t\tnetdev_put(dev, \u0026dev_tracker);\n3642:\t\n3643:\t\treturn rc;\n3644:\t}\n3645:\t\n3646:\tint dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)\n3647:\t{\n3648:\t\tstruct ethtool_devlink_compat *state;\n3649:\t\tu32 ethcmd;\n3650:\t\tint rc;\n3651:\t\n3652:\t\tif (copy_from_user(\u0026ethcmd, useraddr, sizeof(ethcmd)))\n3653:\t\t\treturn -EFAULT;\n3654:\t\n3655:\t\tstate = kzalloc_obj(*state);\n3656:\t\tif (!state)\n3657:\t\t\treturn -ENOMEM;\n3658:\t\n3659:\t\tswitch (ethcmd) {\n3660:\t\tcase ETHTOOL_FLASHDEV:\n3661:\t\t\tif (copy_from_user(\u0026state-\u003eefl, useraddr, sizeof(state-\u003eefl))) {\n3662:\t\t\t\trc = -EFAULT;\n3663:\t\t\t\tgoto exit_free;\n3664:\t\t\t}\n3665:\t\t\tstate-\u003eefl.data[ETHTOOL_FLASH_MAX_FILENAME - 1] = 0;\n3666:\t\t\tbreak;\n3667:\t\t}\n3668:\t\n3669:\t\trc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);\n3670:\t\tif (rc)\n3671:\t\t\tgoto exit_free;\n3672:\t\n3673:\t\tswitch (ethcmd) {\n3674:\t\tcase ETHTOOL_FLASHDEV:\n3675:\t\t\tif (state-\u003edevlink)\n3676:\t\t\t\trc = devlink_compat_flash_update(state-\u003edevlink,\n3677:\t\t\t\t\t\t\t\t state-\u003eefl.data);\n3678:\t\t\tbreak;\n3679:\t\tcase ETHTOOL_GDRVINFO:\n3680:\t\t\tif (state-\u003edevlink)\n3681:\t\t\t\tdevlink_compat_running_version(state-\u003edevlink,\n3682:\t\t\t\t\t\t\t       state-\u003einfo.fw_version,\n3683:\t\t\t\t\t\t\t       sizeof(state-\u003einfo.fw_version));\n3684:\t\t\tif (copy_to_user(useraddr, \u0026state-\u003einfo, sizeof(state-\u003einfo))) {\n"
}

125/3

2026/09/15 11:16

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 47155
							output: 30
							thoughts: 874

Thoughts:

**Analyzing Potential Buffer Overflows in Kernel Code**

Okay, so I'm looking at this `__devlink_compat_running_version` function, and it uses `seq_buf_printf` to build a string. The initial state `state` was allocated with `kzalloc_obj`, so its `info` member should be zeroed out to begin with. The code then uses `nla_for_each_attr_type` and `nla_for_each_nested_type` to iterate through Netlink attributes and uses `seq_buf_printf` to construct a string in a buffer, `buf`. The question here is, what happens to the buffer if `seq_buf_printf` goes wrong, say, if there's an overflow or missing null termination?

Aha, `seq_buf_printf` uses `vsnprintf`. And `vsnprintf`, I *know*, is guaranteed to null-terminate the buffer, even on overflow! Alright, but what if there's a *real* overflow? Let's dig deeper and look at the `seq_buf_vprintf` in `lib/seq_buf.c`.

Okay, here it is: `if (s->len < s->size)` is the crucial check before writing to the buffer. `vsnprintf` writes up to `s->size - s->len` bytes. *Importantly*, even if that results in an overflow, `vsnprintf` is going to ensure there's a null terminator, placed at `s->size - 1`. If there's an overflow, the `seq_buf_set_overflow` function is called and it sets the `s->len` to something larger than the buffer size. Subsequent calls will then find that `s->len >= s->size`, so they won't write anything. Consequently, the buffer will remain null-terminated, which is safe. Plus, `state->info` was zeroed anyway, so the string should be safe even if something went wrong there.

Alright, moving on, let's look at `net/sunrpc/addr.c` and specifically `rpc_sockaddr2uaddr`. This function converts a socket address to a "uaddr" string, using `snprintf`. The code handles both IPv4 and IPv6 addresses. There are two other important functions, `rpc_ntop4` and `rpc_ntop6_noscopeid`. I'll have to figure out what those functions return!

126/3

2026/09/15 11:17

tool

grepper

Args:

{
  "Expression": "rpc_ntop4",
  "PathPrefix": "net/sunrpc/"
}

Results:

{
  "Output": "net/sunrpc/addr.c=104=static size_t rpc_ntop6(const struct sockaddr *sap,\n--\nnet/sunrpc/addr.c-111-\nnet/sunrpc/addr.c:112:static int rpc_ntop4(const struct sockaddr *sap,\nnet/sunrpc/addr.c-113-\t\t     char *buf, const size_t buflen)\n--\nnet/sunrpc/addr.c=129=size_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)\n--\nnet/sunrpc/addr.c-132-\tcase AF_INET:\nnet/sunrpc/addr.c:133:\t\treturn rpc_ntop4(sap, buf, buflen);\nnet/sunrpc/addr.c-134-\tcase AF_INET6:\n--\nnet/sunrpc/addr.c=265=char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)\n--\nnet/sunrpc/addr.c-272-\tcase AF_INET:\nnet/sunrpc/addr.c:273:\t\tlen = rpc_ntop4(sap, addrbuf, sizeof(addrbuf));\nnet/sunrpc/addr.c-274-\t\tif (len == 0 || len \u003e= sizeof(addrbuf))\n"
}

127/3

2026/09/15 11:17

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 48951
							output: 36
							thoughts: 24

Thoughts:

Here's my summary, as if I were thinking these thoughts:

**Analyzing `net/sunrpc/addr.c` - Lines 110-128**

Alright, I need to zero in on a specific section of this file. Let's pull up lines 110 through 128 of `net/sunrpc/addr.c`. This usually means there's some interesting network address-related logic happening there, likely some crucial socket or RPC setup or parsing is going on. I expect it could be dealing with address family handling or possibly some initial socket options or parsing address data during connection establishment. It might relate to address translation between different formats (e.g., IPv4 to IPv6), or maybe even dealing with multicast addresses, which often require special handling. Let's see what the code actually *does* in that region. I'll be looking for any indications of potential bugs, inefficiencies, or areas that could benefit from performance optimization, especially around the interaction with the socket layer and the RPC data structures. This is core networking code, so I need to be thorough.

128/3

2026/09/15 11:17

tool

read-file

Args:

{
  "File": "net/sunrpc/addr.c",
  "FirstLine": 110,
  "LineCount": 20
}

Results:

{
  "Contents": " 110:\t#endif\t/* !IS_ENABLED(CONFIG_IPV6) */\n 111:\t\n 112:\tstatic int rpc_ntop4(const struct sockaddr *sap,\n 113:\t\t\t     char *buf, const size_t buflen)\n 114:\t{\n 115:\t\tconst struct sockaddr_in *sin = (struct sockaddr_in *)sap;\n 116:\t\n 117:\t\treturn snprintf(buf, buflen, \"%pI4\", \u0026sin-\u003esin_addr);\n 118:\t}\n 119:\t\n 120:\t/**\n 121:\t * rpc_ntop - construct a presentation address in @buf\n 122:\t * @sap: socket address\n 123:\t * @buf: construction area\n 124:\t * @buflen: size of @buf, in bytes\n 125:\t *\n 126:\t * Plants a %NUL-terminated string in @buf and returns the length\n 127:\t * of the string, excluding the %NUL.  Otherwise zero is returned.\n 128:\t */\n 129:\tsize_t rpc_ntop(const struct sockaddr *sap, char *buf, const size_t buflen)\n"
}

129/3

2026/09/15 11:17

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 49582
							output: 39
							thoughts: 1489

Thoughts:

**Code Review: String Formatting and Buffer Handling**

Okay, so I've gone through the code snippets, focusing on potential buffer overflow vulnerabilities. It appears the initial concern was regarding string manipulation, specifically around concatenation and formatting within various drivers.

First, I examined `rpc_ntop4`. Here, `rpc_ntop4` correctly sets up `addrbuf`, formats the IP address portion, and then uses `kstrdup` to duplicate the string. There are no immediate issues; the use of `snprintf` combined with the initial null termination ensures safety. The function returns `NULL` on overflow, indicating a well-managed error condition.

Moving onto `sound/pci/ac97/ac97_codec.c`, the previous code used `strlcat`. This code has been updated to use `snprintf` with `strlen` to determine the offset. This pattern is common in several instances. It reads the current length of the destination buffer and then uses the result as an offset for the subsequent `snprintf` call, ensuring that the function formats the string into the appropriate location, and also performs bound checks to make sure we don't overflow the buffer. This is a very robust and correct usage of `snprintf`.

Similarly, `sound/usb/mixer.c` shows the safe usage of `snprintf` within `append_ctl_name`. They are checking the current length with `strlen`, determining whether the string can be written or not. It correctly calculates the remaining space and uses `snprintf` with an offset to append the new string, which addresses any potential overflows.

`drivers/media/dvb-frontends/si2165.c` uses `snprintf` directly, which eliminates any concern about manually managing concatenation. It provides the full length of the destination and uses `snprintf` safely.

`drivers/net/ethernet/intel/i40e/i40e.h` also shows a safe use of `snprintf`.  It calculates the offset in the buffer based on the current length, which is safe.  It checks the length and ensures the destination buffer is not overflown.

Finally, `drivers/net/wireless/ath/wil6210/wmi.c` uses a combination of techniques with a `seq_buf`. This abstraction looks interesting, but at the end, `seq_buf_str(&s)` ensures proper null termination of the resulting string. I'd need to examine the `seq_buf` implementation to be *absolutely* sure, but on the surface, this appears to be a safe alternative to manual string manipulation. I also confirmed that `string` is safely passed to the called function.

In conclusion, it seems that there's a good understanding of the risks associated with buffer overflows in this codebase. The use of `snprintf` with proper length checks and offset calculations, or the use of abstractions that provide similar guarantees, demonstrates a focus on safe string manipulation. I am confident in the safety of these code snippets.

130/3

2026/09/15 11:18

tool

grepper

Args:

{
  "Expression": "resume_triggers2string",
  "PathPrefix": "drivers/net/wireless/ath/wil6210/"
}

Results:

{
  "Output": "drivers/net/wireless/ath/wil6210/wmi.c=3100=int wmi_suspend(struct wil6210_priv *wil)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3163-\ndrivers/net/wireless/ath/wil6210/wmi.c:3164:static void resume_triggers2string(u32 triggers, char *string, int str_size)\ndrivers/net/wireless/ath/wil6210/wmi.c-3165-{\n--\ndrivers/net/wireless/ath/wil6210/wmi.c=3192=int wmi_resume(struct wil6210_priv *wil)\n--\ndrivers/net/wireless/ath/wil6210/wmi.c-3210-\t\treturn rc;\ndrivers/net/wireless/ath/wil6210/wmi.c:3211:\tresume_triggers2string(le32_to_cpu(reply.evt.resume_triggers), string,\ndrivers/net/wireless/ath/wil6210/wmi.c-3212-\t\t\t       sizeof(string));\n"
}

131/3

2026/09/15 11:18

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 52058
							output: 33
							thoughts: 901

Thoughts:

**Analyzing String Handling and Potential Vulnerabilities**

Okay, so I'm looking at this code and immediately my attention is drawn to the string handling. Specifically, I see `char string[100];` within `wmi_resume`. It's null-terminated with `seq_buf_str(&s)`, and then used with `wil_dbg_wmi`. Seems straightforward enough, but I always want to make sure I understand the context.

My immediate thought is to check how firmware paths are constructed. I've jumped into `drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c` to see how it's handled, particularly this section:

```c
	snprintf(fwnames[j].path, BRCMF_FW_NAME_LEN, "%s%s%s%s",
		 mp_path, (end == '/') ? "" : "/",
		 mapping_table[i].fw_base,
		 fwnames[j].extension);
```

Ah, `snprintf`. *Good*, it's being used to format the firmware path. This means that the path is null-terminated, which is a key part of preventing buffer overflows. The use of `BRCMF_FW_NAME_LEN` as the buffer size provides another layer of security, making this specific part pretty robust in my opinion. Always good to see proper string formatting and size limitations.

Now, that brings me to the `/chosen` node in the Device Tree, so I check `drivers/of/fdt.c`.  I see this code, which handles the system command line:

```c
	if (!fdt)
		goto handle_cmdline;

	{
		size_t len = strlen(cmdline);

		if (len < COMMAND_LINE_SIZE)
			snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE);
	}
```

Okay, so if the FDT isn't present, it goes to `handle_cmdline`. It uses `snprintf`, which is good.  I like that it's checking the length before appending the config command line. Looks like they're trying to be careful here, which is what I expect.  Essentially, if `fdt` is null, it skips the FDT handling and goes straight to the command line concatenation, which *should* be safe given the use of `snprintf` and the length check.

132/3

2026/09/15 11:21

tool

grepper

Args:

{
  "Expression": "handle_cmdline:",
  "PathPrefix": "drivers/of/fdt.c"
}

Results:

{
  "Output": "drivers/of/fdt.c=1091=int __init early_init_dt_scan_chosen(char *cmdline)\n--\ndrivers/of/fdt.c-1130-\ndrivers/of/fdt.c:1131:handle_cmdline:\ndrivers/of/fdt.c-1132-\t/*\n"
}

133/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 53635
							output: 37
							thoughts: 26

Thoughts:

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Diving into `fdt.c` for Context**

Okay, so I need to understand what's happening with device tree parsing in the `drivers/of/fdt.c` file, specifically from lines 1090 to 1150. Given what I already know about FDT, that section likely handles a specific aspect of node processing or property handling. I'm guessing it might be related to… well, it could be anything, really. I could be looking at initialization, resource assignment, or perhaps some specific error handling related to how the DTB is interpreted. Let me get into those lines and see what's actually going on. This might relate to my current debugging or a deeper dive into DT handling. I suspect this section is relevant to a specific platform I'm working on right now, or maybe related to a recent bug report. Alright, let's get to the code.

134/3

2026/09/15 11:21

tool

read-file

Args:

{
  "File": "drivers/of/fdt.c",
  "FirstLine": 1090,
  "LineCount": 60
}

Results:

{
  "Contents": "1090:\t\n1091:\tint __init early_init_dt_scan_chosen(char *cmdline)\n1092:\t{\n1093:\t\tint l, node;\n1094:\t\tconst char *p;\n1095:\t\tconst void *rng_seed;\n1096:\t\tconst void *fdt = initial_boot_params;\n1097:\t\n1098:\t\tif (!fdt)\n1099:\t\t\tgoto handle_cmdline;\n1100:\t\n1101:\t\tnode = fdt_path_offset(fdt, \"/chosen\");\n1102:\t\tif (node \u003c 0)\n1103:\t\t\tnode = fdt_path_offset(fdt, \"/chosen@0\");\n1104:\t\tif (node \u003c 0)\n1105:\t\t\t/* Handle the cmdline config options even if no /chosen node */\n1106:\t\t\tgoto handle_cmdline;\n1107:\t\n1108:\t\tchosen_node_offset = node;\n1109:\t\n1110:\t\tearly_init_dt_check_for_initrd(node);\n1111:\t\tearly_init_dt_check_for_elfcorehdr(node);\n1112:\t\tearly_init_dt_check_for_dmcryptkeys(node);\n1113:\t\n1114:\t\trng_seed = of_get_flat_dt_prop(node, \"rng-seed\", \u0026l);\n1115:\t\tif (rng_seed \u0026\u0026 l \u003e 0) {\n1116:\t\t\tadd_bootloader_randomness(rng_seed, l);\n1117:\t\n1118:\t\t\t/* try to clear seed so it won't be found. */\n1119:\t\t\tfdt_nop_property(initial_boot_params, node, \"rng-seed\");\n1120:\t\n1121:\t\t\t/* update CRC check value */\n1122:\t\t\tof_fdt_crc32 = crc32_be(~0, initial_boot_params,\n1123:\t\t\t\t\tfdt_totalsize(initial_boot_params));\n1124:\t\t}\n1125:\t\n1126:\t\t/* Retrieve command line */\n1127:\t\tp = of_get_flat_dt_prop(node, \"bootargs\", \u0026l);\n1128:\t\tif (p != NULL \u0026\u0026 l \u003e 0)\n1129:\t\t\tstrscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));\n1130:\t\n1131:\thandle_cmdline:\n1132:\t\t/*\n1133:\t\t * CONFIG_CMDLINE is meant to be a default in case nothing else\n1134:\t\t * managed to set the command line, unless CONFIG_CMDLINE_FORCE\n1135:\t\t * is set in which case we override whatever was found earlier.\n1136:\t\t */\n1137:\t#ifdef CONFIG_CMDLINE\n1138:\t#if defined(CONFIG_CMDLINE_EXTEND)\n1139:\t\t{\n1140:\t\t\tsize_t len = strlen(cmdline);\n1141:\t\n1142:\t\t\tif (len \u003c COMMAND_LINE_SIZE)\n1143:\t\t\t\tsnprintf(cmdline + len, COMMAND_LINE_SIZE - len, \" %s\", CONFIG_CMDLINE);\n1144:\t\t}\n1145:\t#elif defined(CONFIG_CMDLINE_FORCE)\n1146:\t\tstrscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);\n1147:\t#else\n1148:\t\t/* No arguments from boot loader, use kernel's  cmdl*/\n1149:\t\tif (!((char *)cmdline)[0])\n"
}

135/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 54875
							output: 43
							thoughts: 1046

Thoughts:

**Analyzing String Formatting in Kernel Code**

Okay, so I'm looking at this `early_init_dt_scan_chosen` function, which from the looks of it, is an initialization routine that runs very early in the boot process. I'm wondering about string manipulation in the kernel.

First, I examined `drivers/pinctrl/samsung/pinctrl-samsung.c`. The code uses `snprintf` to construct a pin bank name. Standard, nothing unusual there.

Then, I shifted my focus to `drivers/scsi/bfa/bfa_fcs.c`. Here, the code uses `snprintf` to create symbolic names (`sym_name` and `node_sym_name`) for Fibre Channel ports. It concatenates various pieces of information like the model, version, machine name, and OS details, separated by `BFA_FCS_PORT_SYMBNAME_SEPARATOR`. I have to wonder, though, are these symbolic names sent over the Fibre Channel, or potentially exposed to userspace? That's a security consideration.

To answer that question, I need to understand how these names are used. So, I need to check `bfa_fcs_fabric_psymb_init` and `bfa_fcs_fabric_nsymb_init`.

Wait, in `bfa_fcs_fabric_psymb_init`... let's see what changed!

I see that `port_cfg->sym_name.symname` *used* to be constructed using `strscpy` and `strlcat`, which means it would not have been fully zeroed before use, and was instead constructed with the length of the string, and then null-terminated.

Now it's being constructed using `snprintf`. I need to figure out how it's being used. The crucial question: is `port_cfg->sym_name.symname` being initialized to a specific length or a zeroed value? This could have security implications if sensitive data isn't properly handled.

136/3

2026/09/15 11:21

tool

read-file

Args:

{
  "File": "drivers/scsi/bfa/bfa_fcs.c",
  "FirstLine": 755,
  "LineCount": 45
}

Results:

{
  "Contents": " 755:\tbfa_fcs_fabric_psymb_init(struct bfa_fcs_fabric_s *fabric)\n 756:\t{\n 757:\t\tstruct bfa_lport_cfg_s *port_cfg = \u0026fabric-\u003ebport.port_cfg;\n 758:\t\tchar model[BFA_ADAPTER_MODEL_NAME_LEN] = {0};\n 759:\t\tstruct bfa_fcs_driver_info_s *driver_info = \u0026fabric-\u003efcs-\u003edriver_info;\n 760:\t\n 761:\t\tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n 762:\t\n 763:\t\t/*\n 764:\t\t * Host OS Info :\n 765:\t\t * If OS Patch Info is not there, do not truncate any bytes from the\n 766:\t\t * OS name string and instead copy the entire OS info string (64 bytes).\n 767:\t\t */\n 768:\t\tif (driver_info-\u003ehost_os_patch[0] == '\\0') {\n 769:\t\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n 770:\t\t\t\t \"%s%s%s%s%s%s%s%s\",\n 771:\t\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 772:\t\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 773:\t\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 774:\t\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR);\n 775:\t\t} else {\n 776:\t\t\tsnprintf(port_cfg-\u003esym_name.symname, BFA_SYMNAME_MAXLEN,\n 777:\t\t\t\t \"%s%s%s%s%s%s%s%s%s\",\n 778:\t\t\t\t model, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 779:\t\t\t\t driver_info-\u003eversion, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 780:\t\t\t\t driver_info-\u003ehost_machine_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 781:\t\t\t\t driver_info-\u003ehost_os_name, BFA_FCS_PORT_SYMBNAME_SEPARATOR,\n 782:\t\t\t\t driver_info-\u003ehost_os_patch);\n 783:\t\t}\n 784:\t\n 785:\t\t/* null terminate */\n 786:\t\tport_cfg-\u003esym_name.symname[BFA_SYMNAME_MAXLEN - 1] = 0;\n 787:\t}\n 788:\t\n 789:\t/*\n 790:\t * Node Symbolic Name Creation for base port and all vports\n 791:\t */\n 792:\tvoid\n 793:\tbfa_fcs_fabric_nsymb_init(struct bfa_fcs_fabric_s *fabric)\n 794:\t{\n 795:\t\tstruct bfa_lport_cfg_s *port_cfg = \u0026fabric-\u003ebport.port_cfg;\n 796:\t\tchar model[BFA_ADAPTER_MODEL_NAME_LEN] = {0};\n 797:\t\tstruct bfa_fcs_driver_info_s *driver_info = \u0026fabric-\u003efcs-\u003edriver_info;\n 798:\t\n 799:\t\tbfa_ioc_get_adapter_model(\u0026fabric-\u003efcs-\u003ebfa-\u003eioc, model);\n"
}

137/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 57343
							output: 40
							thoughts: 1513

Thoughts:

**Analyzing String Concatenation and Safety**

Okay, so I'm looking at this code and immediately I see a pattern regarding string manipulation, specifically concatenation, and I need to assess its safety. First, I noticed this initial snippet where `strscpy` is used, followed by `strlcat`. I recall, `strlcat` has inherent safety features with the `strlcat` vs `snprintf` comparison. However, the use of `snprintf` is cleaner, because `strlcat` is a bit of a relic. It doesn't zero-terminate strings. `snprintf` does terminate the string. `snprintf` is cleaner.

I started digging, and I checked `fs/nfs/nfsroot.c`, which showed `snprintf` replacing multiple calls to `strlcat`. Good, safe practice there. The code neatly handles the comma insertion and the source string concatenation within a single call. This is the correct way, avoiding multiple operations, and it's cleaner.

Then I moved to `fs/orangefs/orangefs-debugfs.c`. In this function `orangefs_prepare_debugfs_help_string`, I noticed a potential problem. This `new` string allocation seems a bit involved. Specifically, I'm concerned about how `strlcat` is used multiple times to build the debug help string. The comments mention checking for overflow, but I need to make sure this is actually robust. Looking at the code from lines 630-645, I confirmed that `new` is allocated with `kzalloc`. The critical question is whether using a buffer, such as `seq_buf` will keep the code safe from overflow. Okay, the code using `seq_buf`, and then `strlcpy` is a clean way to do it.

So, in summary, this suggests a gradual shift from `strlcat` to `snprintf` for safer concatenation, and `seq_buf` is a great way to build the resulting string.

138/3

2026/09/15 11:21

tool

read-file

Args:

{
  "File": "fs/orangefs/orangefs-debugfs.c",
  "FirstLine": 630,
  "LineCount": 25
}

Results:

{
  "Contents": " 630:\t\tstruct seq_buf s;\n 631:\t\n 632:\t\tgossip_debug(GOSSIP_UTILS_DEBUG, \"%s: start\\n\", __func__);\n 633:\t\n 634:\t\tif (at_boot)\n 635:\t\t\tclient_title = HELP_STRING_UNINITIALIZED;\n 636:\t\n 637:\t\t/* build a new debug_help_string. */\n 638:\t\tnew = kzalloc(DEBUG_HELP_STRING_SIZE, GFP_KERNEL);\n 639:\t\tif (!new) {\n 640:\t\t\trc = -ENOMEM;\n 641:\t\t\tgoto out;\n 642:\t\t}\n 643:\t\n 644:\t\tseq_buf_init(\u0026s, new, string_size);\n 645:\t\n 646:\t\t/*\n 647:\t\t * We'll just plow through here building our new debug\n 648:\t\t * help string and let seq_buf take care of assuring that\n 649:\t\t * dst doesn't overflow.\n 650:\t\t */\n 651:\t\tseq_buf_puts(\u0026s, client_title);\n 652:\t\n 653:\t\tif (!at_boot) {\n 654:\t\n"
}

139/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 59670
							output: 34
							thoughts: 322

Thoughts:

**Analyzing Potential Uninitialized Memory Access After kzalloc**

Okay, so `new` was kzalloc'ed, which usually means things are zeroed, but I need to be absolutely sure. Let's dig into these modified files and look for any sneaky uninitialized memory accesses. It's easy to miss something subtle, especially with string manipulations.

First, `arch/arm/kernel/atags_parse.c`: in `parse_tag_cmdline`, `default_command_line` seems safe. The code calculates the length using `strlen` of a statically allocated or zeroed buffer and then appends to it using `snprintf`. No obvious issues there.

Now, `arch/loongarch/kernel/setup.c`. `bootcmdline_init` uses a `seq_buf`. This is where I need to be careful. The code initializes `s.buffer`, `s.size`, and `s.len` before using it, which is good. But... wait a minute... does `struct seq_buf` have *other* fields? Are those initialized? I'd better check the definition in `include/linux/seq_buf.h` to see. Gotta be thorough.

140/3

2026/09/15 11:21

tool

grepper

Error:

bad expression: fatal: -e option, 'struct seq_buf {': Unmatched \{

Args:

{
  "Expression": "struct seq_buf {",
  "PathPrefix": "include/linux/seq_buf.h"
}

Results:

{
  "error": "bad expression: fatal: -e option, 'struct seq_buf {': Unmatched \\{"
}

141/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 60314
							output: 35
							thoughts: 22

Thoughts:

Okay, let's dive into this. Here's my take on those initial lines:

**Initial Assessment of `include/linux/seq_buf.h`**

Alright, I'm going to start by getting a handle on the beginning of `include/linux/seq_buf.h`. I'll scan the first forty lines. Usually, that's enough to get a grasp of the basic structure, included headers, and maybe some initial definitions or function prototypes. I expect to see some `#include` directives—likely for standard headers, memory management routines, and potentially some core kernel data structures like linked lists or memory pools if this is related to managing buffers. I'll be looking for the main data structure definition: `struct seq_buf`. Understanding its members is key – pointers to buffers, lengths, read/write pointers, flags... it'll give me a strong indication of how the buffer is managed. I'll pay attention to any inline functions or macros, too; those usually indicate performance-critical operations. The goal is to get a baseline understanding of the buffer's fundamental properties and operations. I will be looking for common features such as adding, reading and removing from buffers, probably some kind of locking mechanism and error handling too.

142/3

2026/09/15 11:21

tool

read-file

Args:

{
  "File": "include/linux/seq_buf.h",
  "FirstLine": 1,
  "LineCount": 40
}

Results:

{
  "Contents": "   1:\t/* SPDX-License-Identifier: GPL-2.0 */\n   2:\t#ifndef _LINUX_SEQ_BUF_H\n   3:\t#define _LINUX_SEQ_BUF_H\n   4:\t\n   5:\t#include \u003clinux/bug.h\u003e\n   6:\t#include \u003clinux/minmax.h\u003e\n   7:\t#include \u003clinux/seq_file.h\u003e\n   8:\t#include \u003clinux/types.h\u003e\n   9:\t\n  10:\t/*\n  11:\t * Trace sequences are used to allow a function to call several other functions\n  12:\t * to create a string of data to use.\n  13:\t */\n  14:\t\n  15:\t/**\n  16:\t * struct seq_buf - seq buffer structure\n  17:\t * @buffer:\tpointer to the buffer\n  18:\t * @size:\tsize of the buffer\n  19:\t * @len:\tthe amount of data inside the buffer\n  20:\t */\n  21:\tstruct seq_buf {\n  22:\t\tchar\t\t\t*buffer;\n  23:\t\tsize_t\t\t\tsize;\n  24:\t\tsize_t\t\t\tlen;\n  25:\t};\n  26:\t\n  27:\t#define DECLARE_SEQ_BUF(NAME, SIZE)\t\t\t\\\n  28:\t\tstruct seq_buf NAME = {\t\t\t\t\\\n  29:\t\t\t.buffer = (char[SIZE]) { 0 },\t\t\\\n  30:\t\t\t.size = SIZE,\t\t\t\t\\\n  31:\t\t}\n  32:\t\n  33:\tstatic inline void seq_buf_clear(struct seq_buf *s)\n  34:\t{\n  35:\t\ts-\u003elen = 0;\n  36:\t\tif (s-\u003esize)\n  37:\t\t\ts-\u003ebuffer[0] = '\\0';\n  38:\t}\n  39:\t\n  40:\tstatic inline void\n"
}

143/3

2026/09/15 11:21

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 61130
							output: 317
							thoughts: 2450

Thoughts:

**Analysis of Memory Safety in the Kernel Codebase**

Okay, so I've gone through this list of code snippets, and I'm pretty confident in the overall memory safety profile. I'm seeing a consistent pattern of using safe string manipulation functions, particularly `snprintf` and `strscpy`, alongside the `seq_buf` utility, to prevent uninitialized memory reads and potential buffer overflows.

Initially, I looked at how `struct seq_buf` is used, and in all cases across architectures (`loongarch`, `parisc`) and diverse drivers (comedi, drm, xe, input, media, net, etc.) the buffers are initialized correctly. That's a good starting point. The buffer, size and length fields are consistently initialized before any operation. Furthermore, the `seq_buf` methods, such as `seq_buf_printf` and `seq_buf_str`, are being utilized correctly, ensuring null termination and bounded writes. This is in contrast to `strcat` that can be dangerous.

The cases of `snprintf` are also reassuring. In various contexts, including command lines, device names, and debug output (e.g., `si2165.c`, `i40e.h`, `fdt.c`, `pinctrl-samsung.c`, `bfa_fcs.c`, `nfsroot.c`, `ac97_codec.c`, `card.c`, `mixer.c`), it’s being used to format strings into buffers of known size, which avoids overflows. The use of `strscpy` after `snprintf` in the `x86/kernel/setup.c` code ensures the string is copied safely and null-terminated.

Looking for the 4 criteria for `NeedsKMSAN` I can see no evidence of them. There are no kernel structures passed to user space that aren't fully initialized, no conditional logic depending on uninitialized data, and no complex data structures where uninitialized fields are read. The code carefully uses bounded and safe writes, and no uninitialized memory leaks appear to be present.

Crucially, in the code sections I've analyzed, particularly in those involving `seq_buf` and string manipulation, the buffers are either explicitly initialized, *kzalloc*'d, or the lengths are carefully managed. Any potential overflow issues would be caught by KASAN and FORTIFY_SOURCE.

Therefore, my assessment is that `NeedsKMSAN` is false for all these cases. I'm ready to call `set-results`.

144/3

2026/09/15 11:22

tool

set-results

Args:

{
  "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

Results:

{
  "KMSANReasoning": "The patch series replaces usages of the deprecated strlcat() function across various kernel subsystems (architecture setup code, drivers, sound, networking, fs) with safer alternatives such as snprintf(), strscpy(), and the seq_buf API.\n\nAnalysis of potential uninitialized memory risks:\n1. All local and heap buffers involved in string manipulation are either zero-initialized (e.g. kzalloc in comedi_bond, sound cards, devlink state, orangefs) or explicitly formatted via snprintf/seq_buf which ensures proper NUL-termination.\n2. Where seq_buf is initialized manually (e.g., in LoongArch and PA-RISC setup), all three fields of struct seq_buf (buffer, size, len) are explicitly populated.\n3. Buffers copied to user space (such as debugfs read callbacks in xe_gt_sriov_pf_debugfs.c and ethtool GDRVINFO via devlink) only copy the explicitly written bytes (using seq_buf_used() or strlen() on NUL-terminated strings).\n4. No uninitialized memory, padding leaks, or uninitialized branch conditions are introduced.\n\nAny string boundary issues or buffer overflows would be detected by KASAN or FORTIFY_SOURCE. As there are no uninitialized memory or information leak risks introduced, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}