AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/09/21 01:50	flow	patch-triage	2m Args: null Results: { "EnableConfigs": [ "SND_USB_LINE6", "SND_USB_POD", "SND_USB_PODHD", "SND_USB_TONEPORT" ], "FocusSymbols": [ "submit_audio_out_urb", "line6_submit_audio_out_all_urbs", "audio_out_callback", "snd_line6_trigger" ], "KMSANReasoning": "The patch adds a bounds check (`fsize = min(fsize, line6pcm-\u003emax_packet_size_out)`) in `submit_audio_out_urb()` in `sound/usb/line6/playback.c`. \n\nPrior to this fix, if `fsize` exceeded `max_packet_size_out`, the cumulative `urb_size` could exceed the buffer allocated for each URB (`LINE6_ISO_PACKETS * max_packet_size_out`), resulting in slab out-of-bounds reads/writes during `memcpy()`, `memset()`, or USB transmission. Out-of-bounds accesses and buffer overflows are explicitly within the domain of KASAN, not KMSAN.\n\nThe patch does not introduce new allocations, does not read or branch on uninitialized variables, does not expose kernel memory to user space (info-leak), and does not cause surrounding code to read uninitialized buffer bytes. The buffer contents are explicitly populated either from the PCM runtime DMA buffer or zeroed with `memset()` for the full length of the transfer. Therefore, standard KASAN fuzzing is sufficient and a dedicated KMSAN session is not required.", "NeedsKMSAN": false, "Reasoning": "The patch modifies the calculation of playback URB packet size in the Line6 USB sound driver by clamping fsize to max_packet_size_out, preventing buffer overflows. Line6 USB audio devices can be emulated via USB gadget/raw-gadget in virtualized environments and exercised via standard ALSA PCM interfaces, making this reachable code worth fuzzing for boundary conditions and playback stability.", "WorthFuzzing": true }
1/1	2026/09/21 01:50	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 606a17c192944e903dd539eb7ac1d6c57c0b7e89\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Sep 21 01:50:07 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c\nindex 7ebaf125f9692..cfb20585c5ead 100644\n--- a/sound/usb/line6/playback.c\n+++ b/sound/usb/line6/playback.c\n@@ -181,6 +181,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n \t\t}\n \n \t\tfsize = bytes_per_frame;\n+\t\tfsize = min(fsize, line6pcm-\u003emax_packet_size_out);\n \n \t\tfout-\u003eoffset = urb_size;\n \t\tfout-\u003elength = fsize;\n" }
2/1	2026/09/21 01:50	agent	patch-evaluator	1m Model: core Args: null Results: { "EnableConfigs": [ "SND_USB_LINE6", "SND_USB_POD", "SND_USB_PODHD", "SND_USB_TONEPORT" ], "FocusSymbols": [ "submit_audio_out_urb", "line6_submit_audio_out_all_urbs", "audio_out_callback", "snd_line6_trigger" ], "Reasoning": "The patch modifies the calculation of playback URB packet size in the Line6 USB sound driver by clamping fsize to max_packet_size_out, preventing buffer overflows. Line6 USB audio devices can be emulated via USB gadget/raw-gadget in virtualized environments and exercised via standard ALSA PCM interfaces, making this reachable code worth fuzzing for boundary conditions and playback stability.", "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 606a17c192944e903dd539eb7ac1d6c57c0b7e89 Author: syz-cluster <triage@syzkaller.com> Date: Mon Sep 21 01:50:07 2026 +0000 syz-cluster: applied patch under review diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c index 7ebaf125f9692..cfb20585c5ead 100644 --- a/sound/usb/line6/playback.c +++ b/sound/usb/line6/playback.c @@ -181,6 +181,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm line6pcm) } fsize = bytes_per_frame; + fsize = min(fsize, line6pcm->max_packet_size_out); fout->offset = urb_size; fout->length = fsize;
3/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 2854 output: 38 thoughts: 242 Thoughts: Analyzing a USB Audio Driver Patch Okay, so I'm looking at this patch for `sound/usb/line6/playback.c`. Seems like a straightforward fix, but let's dive in. The core of the change is this line, `fsize = min(fsize, line6pcm->max_packet_size_out);`. I immediately see this is about limiting the size of the audio data being submitted in an USB transfer. The variable `fsize` likely represents the calculated frame size, probably based on sample rate, number of channels, and bit depth. The `line6pcm->max_packet_size_out` seems to be the maximum USB packet size the device can handle for output. My initial thought is this is probably a good idea to prevent buffer overflows or other USB transfer issues. Without it, `fsize` could potentially be calculated larger than what the USB device or driver can handle, leading to glitches, dropouts, or even crashes. The `min()` function ensures that the submitted data size never exceeds the hardware's capabilities. Now, I want to confirm my understanding. I need to understand the context around this change to confirm my initial hypothesis. Is this fixing a specific issue? What's the potential impact of this change? Let me use `read-file` or `grepper` to examine the surrounding code in `sound/usb/line6/playback.c` around line 181, maybe there's a comment or previous commit that provides more context. I'll also want to look at the surrounding code to determine how `fsize` is calculated. This will give me a better understanding of the problem this is fixing.
4/2	2026/09/21 01:50	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 160, "LineCount": 50 } Results: { "Contents": " 160:\t\t\treturn -EINVAL;\n 161:\t\t}\n 162:\t\n 163:\t\turb_out = line6pcm-\u003eout.urbs[index];\n 164:\t\turb_size = 0;\n 165:\t\n 166:\t\t/* TODO: this may not work for LINE6_ISO_PACKETS != 1 /\n 167:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\n 168:\t\t\t/ compute frame size for given sampling rate /\n 169:\t\t\tint fsize = 0;\n 170:\t\t\tstruct usb_iso_packet_descriptor fout =\n 171:\t\t\t \u0026urb_out-\u003eiso_frame_desc[i];\n 172:\t\n 173:\t\t\tfsize = line6pcm-\u003eprev_fsize;\n 174:\t\t\tif (fsize == 0) {\n 175:\t\t\t\tint n;\n 176:\t\n 177:\t\t\t\tline6pcm-\u003eout.count += frame_increment;\n 178:\t\t\t\tn = line6pcm-\u003eout.count / frame_factor;\n 179:\t\t\t\tline6pcm-\u003eout.count -= n * frame_factor;\n 180:\t\t\t\tfsize = n;\n 181:\t\t\t}\n 182:\t\n 183:\t\t\tfsize = bytes_per_frame;\n 184:\t\t\tfsize = min(fsize, line6pcm-\u003emax_packet_size_out);\n 185:\t\n 186:\t\t\tfout-\u003eoffset = urb_size;\n 187:\t\t\tfout-\u003elength = fsize;\n 188:\t\t\turb_size += fsize;\n 189:\t\t}\n 190:\t\n 191:\t\tif (urb_size == 0) {\n 192:\t\t\t/ can't determine URB size /\n 193:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"driver bug: urb_size = 0\\n\");\n 194:\t\t\treturn -EINVAL;\n 195:\t\t}\n 196:\t\n 197:\t\turb_frames = urb_size / bytes_per_frame;\n 198:\t\turb_out-\u003etransfer_buffer =\n 199:\t\t line6pcm-\u003eout.buffer +\n 200:\t\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\n 201:\t\turb_out-\u003etransfer_buffer_length = urb_size;\n 202:\t\turb_out-\u003econtext = line6pcm;\n 203:\t\n 204:\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running) \u0026\u0026\n 205:\t\t !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags)) {\n 206:\t\t\tstruct snd_pcm_runtime *runtime =\n 207:\t\t\t get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK)-\u003eruntime;\n 208:\t\n 209:\t\t\tif (line6pcm-\u003eout.pos + urb_frames \u003e runtime-\u003ebuffer_size) {\n" }
5/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 4321 output: 29 thoughts: 255 Thoughts: My Assessment of the `sound/usb/line6/` Driver's Fuzzing Potential Okay, let's analyze this driver, `sound/usb/line6/`. The question is, can it be reached through USB emulation? My experience says "yes, almost certainly." Syzkaller is a powerful tool, and it frequently targets sound/usb drivers, including those like `line6` and `snd-usb-audio`, through its USB fuzzing capabilities. I see that Syzkaller utilizes `syz_usb_connect` and `raw_gadget`, which simulate USB devices. So, that's a good starting point. Now, a crucial question: can I probe these line6 USB devices using a USB gadget or raw_gadget setup within a QEMU environment? Considering my understanding of USB driver architecture and virtual buses, the answer is highly likely, yes. USB drivers are designed to be accessible through these virtualized buses. I need to confirm this against the primary criteria: "REACHABILITY IS THE PRIMARY GATE." Fuzzing is only useful if the code can actually be executed within a standard virtualized environment like QEMU. That means we have to rely on software-emulated devices like USB gadgets or tun/tap. My understanding of "Reachable Drivers and Protocols" confirms that USB gadget emulation is exactly the kind of virtual bus we're talking about here. This driver seems to fit the bill. Now, let me quickly double-check the Kconfig entry for `sound/usb/line6` to make sure it's even enabled for the targeted configurations.
6/2	2026/09/21 01:50	tool	grepper	0m Args: { "Expression": "LINE6", "PathPrefix": "sound/usb/line6/" } Results: { "Output": "\nFull output is too long, showing 500 out of 917 lines.\nUse more precise expression if possible.\n\nsound/usb/line6/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nsound/usb/line6/Kconfig:2:config SND_USB_LINE6\nsound/usb/line6/Kconfig-3-\ttristate\n--\nsound/usb/line6/Kconfig=8=config SND_USB_POD\nsound/usb/line6/Kconfig-9-\ttristate \"Line 6 POD USB support\"\nsound/usb/line6/Kconfig:10:\tselect SND_USB_LINE6\nsound/usb/line6/Kconfig-11-\thelp\n--\nsound/usb/line6/Kconfig=25=config SND_USB_PODHD\nsound/usb/line6/Kconfig-26-\ttristate \"Line 6 POD X3/HD300/400/500 USB support\"\nsound/usb/line6/Kconfig:27:\tselect SND_USB_LINE6\nsound/usb/line6/Kconfig-28-\thelp\n--\nsound/usb/line6/Kconfig=31=config SND_USB_TONEPORT\nsound/usb/line6/Kconfig-32-\ttristate \"TonePort GX, UX1 and UX2 USB support\"\nsound/usb/line6/Kconfig:33:\tselect SND_USB_LINE6\nsound/usb/line6/Kconfig-34-\tselect NEW_LEDS\n--\nsound/usb/line6/Kconfig=39=config SND_USB_VARIAX\nsound/usb/line6/Kconfig-40-\ttristate \"Variax Workbench USB support\"\nsound/usb/line6/Kconfig:41:\tselect SND_USB_LINE6\nsound/usb/line6/Kconfig-42-\thelp\n--\nsound/usb/line6/Makefile=13=snd-usb-variax-y := variax.o\nsound/usb/line6/Makefile-14-\nsound/usb/line6/Makefile:15:obj-$(CONFIG_SND_USB_LINE6)\t+= snd-usb-line6.o\nsound/usb/line6/Makefile-16-obj-$(CONFIG_SND_USB_POD)\t+= snd-usb-pod.o\n--\nsound/usb/line6/capture.c=21=static int submit_audio_in_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/capture.c-38-\nsound/usb/line6/capture.c:39:\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\nsound/usb/line6/capture.c-40-\t\tstruct usb_iso_packet_descriptor fin =\n--\nsound/usb/line6/capture.c-48-\t line6pcm-\u003ein.buffer +\nsound/usb/line6/capture.c:49:\t index * LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_in;\nsound/usb/line6/capture.c-50-\turb_in-\u003etransfer_buffer_length = urb_size;\n--\nsound/usb/line6/capture.c=145=static void audio_in_callback(struct urb urb)\n--\nsound/usb/line6/capture.c-158-\nsound/usb/line6/capture.c:159:\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\nsound/usb/line6/capture.c-160-\t\tchar fbuf;\n--\nsound/usb/line6/capture.c-179-\nsound/usb/line6/capture.c:180:\t\tBUILD_BUG_ON_MSG(LINE6_ISO_PACKETS != 1,\nsound/usb/line6/capture.c:181:\t\t\t\"The following code assumes LINE6_ISO_PACKETS == 1\");\nsound/usb/line6/capture.c-182-\t\t/* TODO:\n--\nsound/usb/line6/capture.c-193-\nsound/usb/line6/capture.c:194:\t\tif (!test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c:195:\t\t test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c-196-\t\t fsize \u003e 0)\n--\nsound/usb/line6/capture.c-207-\nsound/usb/line6/capture.c:208:\t\tif (!test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c:209:\t\t test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running))\nsound/usb/line6/capture.c-210-\t\t\tline6_capture_check_period(line6pcm, length);\n--\nsound/usb/line6/capture.c=215=static int snd_line6_capture_open(struct snd_pcm_substream substream)\n--\nsound/usb/line6/capture.c-226-\nsound/usb/line6/capture.c:227:\tline6_pcm_acquire(line6pcm, LINE6_STREAM_CAPTURE_HELPER, false);\nsound/usb/line6/capture.c-228-\n--\nsound/usb/line6/capture.c=234=static int snd_line6_capture_close(struct snd_pcm_substream substream)\n--\nsound/usb/line6/capture.c-237-\nsound/usb/line6/capture.c:238:\tline6_pcm_release(line6pcm, LINE6_STREAM_CAPTURE_HELPER);\nsound/usb/line6/capture.c-239-\treturn 0;\n--\nsound/usb/line6/capture.c=253=int line6_create_audio_in_urbs(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/capture.c-267-\t\turb = line6pcm-\u003ein.urbs[i] =\nsound/usb/line6/capture.c:268:\t\t usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);\nsound/usb/line6/capture.c-269-\n--\nsound/usb/line6/capture.c-279-\t\turb-\u003estart_frame = -1;\nsound/usb/line6/capture.c:280:\t\turb-\u003enumber_of_packets = LINE6_ISO_PACKETS;\nsound/usb/line6/capture.c:281:\t\turb-\u003einterval = LINE6_ISO_INTERVAL;\nsound/usb/line6/capture.c-282-\t\turb-\u003eerror_count = 0;\n--\nsound/usb/line6/driver.c=62=static int line6_start_listen(struct usb_line6 line6)\n--\nsound/usb/line6/driver.c-65-\nsound/usb/line6/driver.c:66:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c-67-\t\tusb_fill_int_urb(line6-\u003eurb_listen, line6-\u003eusbdev,\nsound/usb/line6/driver.c-68-\t\t\tusb_rcvintpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_r),\nsound/usb/line6/driver.c:69:\t\t\tline6-\u003ebuffer_listen, LINE6_BUFSIZE_LISTEN,\nsound/usb/line6/driver.c-70-\t\t\tline6_data_received, line6, line6-\u003einterval);\n--\nsound/usb/line6/driver.c-73-\t\t\tusb_rcvbulkpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_r),\nsound/usb/line6/driver.c:74:\t\t\tline6-\u003ebuffer_listen, LINE6_BUFSIZE_LISTEN,\nsound/usb/line6/driver.c-75-\t\t\tline6_data_received, line6);\n--\nsound/usb/line6/driver.c=100=int line6_send_raw_message(struct usb_line6 line6, const char buffer,\n--\nsound/usb/line6/driver.c-111-\nsound/usb/line6/driver.c:112:\t\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c-113-\t\t\tretval = usb_interrupt_msg(line6-\u003eusbdev,\n--\nsound/usb/line6/driver.c-115-\t\t\t\t\t\t(char )frag_buf, frag_size,\nsound/usb/line6/driver.c:116:\t\t\t\t\t\t\u0026partial, LINE6_TIMEOUT);\nsound/usb/line6/driver.c-117-\t\t} else {\n--\nsound/usb/line6/driver.c-120-\t\t\t\t\t\t(char )frag_buf, frag_size,\nsound/usb/line6/driver.c:121:\t\t\t\t\t\t\u0026partial, LINE6_TIMEOUT);\nsound/usb/line6/driver.c-122-\t\t}\n--\nsound/usb/line6/driver.c=154=static int line6_send_raw_message_async_part(struct message msg,\n--\nsound/usb/line6/driver.c-161-\nsound/usb/line6/driver.c:162:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c-163-\t\tusb_fill_int_urb(urb, line6-\u003eusbdev,\n--\nsound/usb/line6/driver.c=265=char line6_alloc_sysex_buffer(struct usb_line6 line6, int code1, int code2,\n--\nsound/usb/line6/driver.c-272-\nsound/usb/line6/driver.c:273:\tbuffer[0] = LINE6_SYSEX_BEGIN;\nsound/usb/line6/driver.c-274-\tmemcpy(buffer + 1, line6_midi_id, sizeof(line6_midi_id));\n--\nsound/usb/line6/driver.c-276-\tbuffer[sizeof(line6_midi_id) + 2] = code2;\nsound/usb/line6/driver.c:277:\tbuffer[sizeof(line6_midi_id) + 3 + size] = LINE6_SYSEX_END;\nsound/usb/line6/driver.c-278-\treturn buffer;\n--\nsound/usb/line6/driver.c=285=static void line6_data_received(struct urb urb)\n--\nsound/usb/line6/driver.c-293-\nsound/usb/line6/driver.c:294:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c-295-\t\tscoped_guard(spinlock_irqsave, \u0026line6-\u003eline6midi-\u003elock) {\n--\nsound/usb/line6/driver.c-309-\t\t\t\t\tline6_midibuf_read(mb, line6-\u003ebuffer_message,\nsound/usb/line6/driver.c:310:\t\t\t\t\t\t\t LINE6_MIDI_MESSAGE_MAXLEN,\nsound/usb/line6/driver.c:311:\t\t\t\t\t\t\t LINE6_MIDIBUF_READ_RX);\nsound/usb/line6/driver.c-312-\t\t\t}\n--\nsound/usb/line6/driver.c-333-\nsound/usb/line6/driver.c:334:#define LINE6_READ_WRITE_STATUS_DELAY 2 /* milliseconds /\nsound/usb/line6/driver.c:335:#define LINE6_READ_WRITE_MAX_RETRIES 50\nsound/usb/line6/driver.c-336-\n--\nsound/usb/line6/driver.c=340=int line6_read_data(struct usb_line6 line6, unsigned address, void data,\n--\nsound/usb/line6/driver.c-354-\t\t\t\t (datalen \u003c\u003c 8) \| 0x21, address, NULL, 0,\nsound/usb/line6/driver.c:355:\t\t\t\t LINE6_TIMEOUT, GFP_KERNEL);\nsound/usb/line6/driver.c-356-\tif (ret) {\n--\nsound/usb/line6/driver.c-361-\t/ Wait for data length. We'll get 0xff until length arrives. /\nsound/usb/line6/driver.c:362:\tfor (count = 0; count \u003c LINE6_READ_WRITE_MAX_RETRIES; count++) {\nsound/usb/line6/driver.c:363:\t\tmdelay(LINE6_READ_WRITE_STATUS_DELAY);\nsound/usb/line6/driver.c-364-\n--\nsound/usb/line6/driver.c-367-\t\t\t\t\t 0x0012, 0x0000, \u0026len, 1,\nsound/usb/line6/driver.c:368:\t\t\t\t\t LINE6_TIMEOUT, GFP_KERNEL);\nsound/usb/line6/driver.c-369-\t\tif (ret) {\n--\nsound/usb/line6/driver.c-394-\t\t\t\t USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,\nsound/usb/line6/driver.c:395:\t\t\t\t 0x0013, 0x0000, data, datalen, LINE6_TIMEOUT,\nsound/usb/line6/driver.c-396-\t\t\t\t GFP_KERNEL);\n--\nsound/usb/line6/driver.c=408=int line6_write_data(struct usb_line6 line6, unsigned address, void data,\n--\nsound/usb/line6/driver.c-424-\t\t\t\t USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_OUT,\nsound/usb/line6/driver.c:425:\t\t\t\t 0x0022, address, data, datalen, LINE6_TIMEOUT,\nsound/usb/line6/driver.c-426-\t\t\t\t GFP_KERNEL);\n--\nsound/usb/line6/driver.c-432-\nsound/usb/line6/driver.c:433:\tfor (count = 0; count \u003c LINE6_READ_WRITE_MAX_RETRIES; count++) {\nsound/usb/line6/driver.c:434:\t\tmdelay(LINE6_READ_WRITE_STATUS_DELAY);\nsound/usb/line6/driver.c-435-\n--\nsound/usb/line6/driver.c-437-\t\t\t\t\t USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,\nsound/usb/line6/driver.c:438:\t\t\t\t\t 0x0012, 0x0000, status, 1, LINE6_TIMEOUT,\nsound/usb/line6/driver.c-439-\t\t\t\t\t GFP_KERNEL);\n--\nsound/usb/line6/driver.c=498=static void line6_get_usb_properties(struct usb_line6 line6)\n--\nsound/usb/line6/driver.c-504-\nsound/usb/line6/driver.c:505:\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL) {\nsound/usb/line6/driver.c:506:\t\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c-507-\t\t\tpipe = usb_rcvintpipe(line6-\u003eusbdev,\n--\nsound/usb/line6/driver.c-520-\t} else {\nsound/usb/line6/driver.c:521:\t\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL) {\nsound/usb/line6/driver.c-522-\t\t\tdev_err(line6-\u003eifcdev,\n--\nsound/usb/line6/driver.c-524-\t\t}\nsound/usb/line6/driver.c:525:\t\tline6-\u003einterval = LINE6_FALLBACK_INTERVAL;\nsound/usb/line6/driver.c:526:\t\tline6-\u003emax_packet_size = LINE6_FALLBACK_MAXPACKETSIZE;\nsound/usb/line6/driver.c-527-\t}\n--\nsound/usb/line6/driver.c=605=line6_hwdep_write(struct snd_hwdep hwdep, const char __user data, long count,\n--\nsound/usb/line6/driver.c-611-\nsound/usb/line6/driver.c:612:\tif (count \u003e line6-\u003emax_packet_size * LINE6_RAW_MESSAGES_MAXCOUNT) {\nsound/usb/line6/driver.c-613-\t\t/* This is an arbitrary limit - still better than nothing... /\n--\nsound/usb/line6/driver.c=661=static int line6_hwdep_init(struct usb_line6 line6)\n--\nsound/usb/line6/driver.c-676-\tstrscpy(hwdep-\u003ename, \"config\");\nsound/usb/line6/driver.c:677:\thwdep-\u003eiface = SNDRV_HWDEP_IFACE_LINE6;\nsound/usb/line6/driver.c-678-\thwdep-\u003eops = hwdep_ops;\n--\nsound/usb/line6/driver.c=686=static int line6_init_cap_control(struct usb_line6 line6)\n--\nsound/usb/line6/driver.c-690-\t/ initialize USB buffers: /\nsound/usb/line6/driver.c:691:\tline6-\u003ebuffer_listen = kzalloc(LINE6_BUFSIZE_LISTEN, GFP_KERNEL);\nsound/usb/line6/driver.c-692-\tif (!line6-\u003ebuffer_listen)\n--\nsound/usb/line6/driver.c-698-\nsound/usb/line6/driver.c:699:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c:700:\t\tline6-\u003ebuffer_message = kzalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);\nsound/usb/line6/driver.c-701-\t\tif (!line6-\u003ebuffer_message)\n--\nsound/usb/line6/driver.c=734=int line6_probe(struct usb_interface interface,\n--\nsound/usb/line6/driver.c-795-\nsound/usb/line6/driver.c:796:\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL) {\nsound/usb/line6/driver.c-797-\t\tret = line6_init_cap_control(line6);\n--\nsound/usb/line6/driver.c=863=int line6_suspend(struct usb_interface interface, pm_message_t message)\n--\nsound/usb/line6/driver.c-869-\nsound/usb/line6/driver.c:870:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL)\nsound/usb/line6/driver.c-871-\t\tline6_stop_listen(line6);\n--\nsound/usb/line6/driver.c=883=int line6_resume(struct usb_interface interface)\n--\nsound/usb/line6/driver.c-886-\nsound/usb/line6/driver.c:887:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL)\nsound/usb/line6/driver.c-888-\t\tline6_start_listen(line6);\n--\nsound/usb/line6/driver.h-26-/* Fallback USB interval and max packet size values /\nsound/usb/line6/driver.h:27:#define LINE6_FALLBACK_INTERVAL 10\nsound/usb/line6/driver.h:28:#define LINE6_FALLBACK_MAXPACKETSIZE 16\nsound/usb/line6/driver.h-29-\nsound/usb/line6/driver.h:30:#define LINE6_TIMEOUT 1000\nsound/usb/line6/driver.h:31:#define LINE6_BUFSIZE_LISTEN 64\nsound/usb/line6/driver.h:32:#define LINE6_MIDI_MESSAGE_MAXLEN 256\nsound/usb/line6/driver.h-33-\nsound/usb/line6/driver.h:34:#define LINE6_RAW_MESSAGES_MAXCOUNT_ORDER 7\nsound/usb/line6/driver.h-35-/ 4k packets are common, BUFSIZE * MAXCOUNT should be bigger... /\nsound/usb/line6/driver.h:36:#define LINE6_RAW_MESSAGES_MAXCOUNT (1 \u003c\u003c LINE6_RAW_MESSAGES_MAXCOUNT_ORDER)\nsound/usb/line6/driver.h-37-\nsound/usb/line6/driver.h-38-\nsound/usb/line6/driver.h:39:#if LINE6_BUFSIZE_LISTEN \u003e 65535\nsound/usb/line6/driver.h-40-#error \"Use dynamic fifo instead\"\n--\nsound/usb/line6/driver.h-45-/\nsound/usb/line6/driver.h:46:#define LINE6_PARAM_CHANGE 0xb0\nsound/usb/line6/driver.h:47:#define LINE6_PROGRAM_CHANGE 0xc0\nsound/usb/line6/driver.h:48:#define LINE6_SYSEX_BEGIN 0xf0\nsound/usb/line6/driver.h:49:#define LINE6_SYSEX_END 0xf7\nsound/usb/line6/driver.h:50:#define LINE6_RESET 0xff\nsound/usb/line6/driver.h-51-\n--\nsound/usb/line6/driver.h-55-/\nsound/usb/line6/driver.h:56:#define LINE6_CHANNEL_HOST 0x00\nsound/usb/line6/driver.h-57-\n--\nsound/usb/line6/driver.h-60-/\nsound/usb/line6/driver.h:61:#define LINE6_CHANNEL_DEVICE 0x02\nsound/usb/line6/driver.h-62-\nsound/usb/line6/driver.h:63:#define LINE6_CHANNEL_UNKNOWN 5\t/* don't know yet what this is good for /\nsound/usb/line6/driver.h-64-\nsound/usb/line6/driver.h:65:#define LINE6_CHANNEL_MASK 0x0f\nsound/usb/line6/driver.h-66-\n--\nsound/usb/line6/driver.h=98=enum {\nsound/usb/line6/driver.h-99-\t/ device supports settings parameter via USB /\nsound/usb/line6/driver.h:100:\tLINE6_CAP_CONTROL =\t1 \u003c\u003c 0,\nsound/usb/line6/driver.h-101-\t/ device supports PCM input/output via USB /\nsound/usb/line6/driver.h:102:\tLINE6_CAP_PCM =\t\t1 \u003c\u003c 1,\nsound/usb/line6/driver.h-103-\t/ device supports hardware monitoring /\nsound/usb/line6/driver.h:104:\tLINE6_CAP_HWMON =\t1 \u003c\u003c 2,\nsound/usb/line6/driver.h-105-\t/ device requires output data when input is read /\nsound/usb/line6/driver.h:106:\tLINE6_CAP_IN_NEEDS_OUT = 1 \u003c\u003c 3,\nsound/usb/line6/driver.h-107-\t/ device uses raw MIDI via USB (data endpoints) /\nsound/usb/line6/driver.h:108:\tLINE6_CAP_CONTROL_MIDI = 1 \u003c\u003c 4,\nsound/usb/line6/driver.h-109-\t/ device provides low-level information /\nsound/usb/line6/driver.h:110:\tLINE6_CAP_CONTROL_INFO = 1 \u003c\u003c 5,\nsound/usb/line6/driver.h-111-\t/ device provides hardware monitoring volume control /\nsound/usb/line6/driver.h:112:\tLINE6_CAP_HWMON_CTL =\t1 \u003c\u003c 6,\nsound/usb/line6/driver.h-113-};\n--\nsound/usb/line6/driver.h=119=struct usb_line6 {\n--\nsound/usb/line6/driver.h-168-\t\tunsigned int nonblock:1;\nsound/usb/line6/driver.h:169:\t\tSTRUCT_KFIFO_REC_2(LINE6_BUFSIZE_LISTEN LINE6_RAW_MESSAGES_MAXCOUNT)\nsound/usb/line6/driver.h-170-\t\t\tfifo;\n--\nsound/usb/line6/midi.c=37=static void line6_midi_transmit(struct snd_rawmidi_substream substream)\n--\nsound/usb/line6/midi.c-42-\tstruct midi_buffer mb = \u0026line6midi-\u003emidibuf_out;\nsound/usb/line6/midi.c:43:\tunsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];\nsound/usb/line6/midi.c-44-\tint req, done;\n--\nsound/usb/line6/midi.c-47-\t\treq = min3(line6_midibuf_bytes_free(mb), line6-\u003emax_packet_size,\nsound/usb/line6/midi.c:48:\t\t\t LINE6_FALLBACK_MAXPACKETSIZE);\nsound/usb/line6/midi.c-49-\t\tdone = snd_rawmidi_transmit_peek(substream, chunk, req);\n--\nsound/usb/line6/midi.c-59-\t\tdone = line6_midibuf_read(mb, chunk,\nsound/usb/line6/midi.c:60:\t\t\t\t\t LINE6_FALLBACK_MAXPACKETSIZE,\nsound/usb/line6/midi.c:61:\t\t\t\t\t LINE6_MIDIBUF_READ_TX);\nsound/usb/line6/midi.c-62-\n--\nsound/usb/line6/midi.c=252=int line6_init_midi(struct usb_line6 line6)\n--\nsound/usb/line6/midi.c-257-\nsound/usb/line6/midi.c:258:\tif (!(line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI)) {\nsound/usb/line6/midi.c-259-\t\t/ skip MIDI initialization and report success /\n--\nsound/usb/line6/midibuf.c=123=int line6_midibuf_read(struct midi_buffer this, unsigned char data,\n--\nsound/usb/line6/midibuf.c-153-\t /\nsound/usb/line6/midibuf.c:154:\tif (read_type == LINE6_MIDIBUF_READ_RX) {\nsound/usb/line6/midibuf.c-155-\t\tif (command == 0xb2 \|\| command == 0xc2 \|\| command == 0xf2) {\n--\nsound/usb/line6/midibuf.h-10-\nsound/usb/line6/midibuf.h:11:#define LINE6_MIDIBUF_READ_TX 0\nsound/usb/line6/midibuf.h:12:#define LINE6_MIDIBUF_READ_RX 1\nsound/usb/line6/midibuf.h-13-\n--\nsound/usb/line6/pcm.c=39=static int snd_line6_impulse_volume_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-50-\tif (value \u003e 0) {\nsound/usb/line6/pcm.c:51:\t\terr = line6_pcm_acquire(line6pcm, LINE6_STREAM_IMPULSE, true);\nsound/usb/line6/pcm.c-52-\t\tif (err \u003c 0) {\n--\nsound/usb/line6/pcm.c-56-\t} else {\nsound/usb/line6/pcm.c:57:\t\tline6_pcm_release(line6pcm, LINE6_STREAM_IMPULSE);\nsound/usb/line6/pcm.c-58-\t}\n--\nsound/usb/line6/pcm.c=147=static int line6_buffer_acquire(struct snd_line6_pcm line6pcm,\n--\nsound/usb/line6/pcm.c-158-\t\t\tkmalloc(array3_size(line6pcm-\u003eline6-\u003eiso_buffers,\nsound/usb/line6/pcm.c:159:\t\t\t\t\t LINE6_ISO_PACKETS, pkt_size),\nsound/usb/line6/pcm.c-160-\t\t\t\tGFP_KERNEL);\n--\nsound/usb/line6/pcm.c=225=int snd_line6_trigger(struct snd_pcm_substream substream, int cmd)\n--\nsound/usb/line6/pcm.c-230-\nsound/usb/line6/pcm.c:231:\tclear_bit(LINE6_FLAG_PREPARED, \u0026line6pcm-\u003eflags);\nsound/usb/line6/pcm.c-232-\n--\nsound/usb/line6/pcm.c-241-\t\t\t\t(line6pcm-\u003eline6-\u003eproperties-\u003ecapabilities \u0026\nsound/usb/line6/pcm.c:242:\t\t\t\t\tLINE6_CAP_IN_NEEDS_OUT)) {\nsound/usb/line6/pcm.c-243-\t\t\t\terr = line6_stream_start(line6pcm, SNDRV_PCM_STREAM_PLAYBACK,\nsound/usb/line6/pcm.c:244:\t\t\t\t\t\t LINE6_STREAM_CAPTURE_HELPER);\nsound/usb/line6/pcm.c-245-\t\t\t\tif (err \u003c 0)\n--\nsound/usb/line6/pcm.c-248-\t\t\terr = line6_stream_start(line6pcm, s-\u003estream,\nsound/usb/line6/pcm.c:249:\t\t\t\t\t\t LINE6_STREAM_PCM);\nsound/usb/line6/pcm.c-250-\t\t\tif (err \u003c 0)\n--\nsound/usb/line6/pcm.c-257-\t\t\t\t(line6pcm-\u003eline6-\u003eproperties-\u003ecapabilities \u0026\nsound/usb/line6/pcm.c:258:\t\t\t\t\tLINE6_CAP_IN_NEEDS_OUT)) {\nsound/usb/line6/pcm.c-259-\t\t\t\tline6_stream_stop(line6pcm, SNDRV_PCM_STREAM_PLAYBACK,\nsound/usb/line6/pcm.c:260:\t\t\t\t\t LINE6_STREAM_CAPTURE_HELPER);\nsound/usb/line6/pcm.c-261-\t\t\t}\nsound/usb/line6/pcm.c-262-\t\t\tline6_stream_stop(line6pcm, s-\u003estream,\nsound/usb/line6/pcm.c:263:\t\t\t\t\t LINE6_STREAM_PCM);\nsound/usb/line6/pcm.c-264-\t\t\tbreak;\n--\nsound/usb/line6/pcm.c-268-\t\t\t\treturn -EINVAL;\nsound/usb/line6/pcm.c:269:\t\t\tset_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags);\nsound/usb/line6/pcm.c-270-\t\t\tbreak;\n--\nsound/usb/line6/pcm.c-274-\t\t\t\treturn -EINVAL;\nsound/usb/line6/pcm.c:275:\t\t\tclear_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags);\nsound/usb/line6/pcm.c-276-\t\t\tbreak;\n--\nsound/usb/line6/pcm.c=315=EXPORT_SYMBOL_GPL(line6_pcm_release);\n--\nsound/usb/line6/pcm.c-317-/ Acquire and optionally start duplex streams:\nsound/usb/line6/pcm.c:318: * type is either LINE6_STREAM_IMPULSE or LINE6_STREAM_MONITOR\nsound/usb/line6/pcm.c-319- /\n--\nsound/usb/line6/pcm.c=350=int snd_line6_hw_params(struct snd_pcm_substream substream,\n--\nsound/usb/line6/pcm.c-358-\tret = line6_buffer_acquire(line6pcm, pstr, substream-\u003estream,\nsound/usb/line6/pcm.c:359:\t LINE6_STREAM_PCM);\nsound/usb/line6/pcm.c-360-\tif (ret \u003c 0)\n--\nsound/usb/line6/pcm.c=368=int snd_line6_hw_free(struct snd_pcm_substream substream)\n--\nsound/usb/line6/pcm.c-373-\tguard(mutex)(\u0026line6pcm-\u003estate_mutex);\nsound/usb/line6/pcm.c:374:\tline6_buffer_release(line6pcm, pstr, LINE6_STREAM_PCM);\nsound/usb/line6/pcm.c-375-\treturn 0;\n--\nsound/usb/line6/pcm.c=515=int line6_init_pcm(struct usb_line6 line6,\n--\nsound/usb/line6/pcm.c-523-\nsound/usb/line6/pcm.c:524:\tif (!(line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_PCM))\nsound/usb/line6/pcm.c-525-\t\treturn 0;\t/* skip PCM initialization and report success /\n--\nsound/usb/line6/pcm.c-543-\tspin_lock_init(\u0026line6pcm-\u003ein.lock);\nsound/usb/line6/pcm.c:544:\tline6pcm-\u003eimpulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;\nsound/usb/line6/pcm.c-545-\n--\nsound/usb/line6/pcm.c=584=int snd_line6_prepare(struct snd_pcm_substream substream)\n--\nsound/usb/line6/pcm.c-592-\nsound/usb/line6/pcm.c:593:\tif (!test_and_set_bit(LINE6_FLAG_PREPARED, \u0026line6pcm-\u003eflags)) {\nsound/usb/line6/pcm.c-594-\t\tline6pcm-\u003eout.count = 0;\n--\nsound/usb/line6/pcm.h-24-/\nsound/usb/line6/pcm.h:25:#define LINE6_ISO_PACKETS\t1\nsound/usb/line6/pcm.h-26-\n--\nsound/usb/line6/pcm.h-29- /\nsound/usb/line6/pcm.h:30:#define LINE6_ISO_INTERVAL\t1\nsound/usb/line6/pcm.h-31-\nsound/usb/line6/pcm.h:32:#define LINE6_IMPULSE_DEFAULT_PERIOD 100\nsound/usb/line6/pcm.h-33-\n--\nsound/usb/line6/pcm.h-54-\tor capture stream. Both can contain the bit flag corresponding to\nsound/usb/line6/pcm.h:55:\tLINE6_STREAM_* type,\nsound/usb/line6/pcm.h:56:\t LINE6_STREAM_PCM = ALSA PCM playback or capture\nsound/usb/line6/pcm.h:57:\t LINE6_STREAM_MONITOR = software monitoring\nsound/usb/line6/pcm.h-58-\t IMPULSE = optional impulse response measurement\n--\nsound/usb/line6/pcm.h-63-\tline6_pcm_acquire() or line6_pcm_release() with the appropriate\nsound/usb/line6/pcm.h:64:\tLINE6_STREAM_* flag.\nsound/usb/line6/pcm.h-65-/\n--\nsound/usb/line6/pcm.h=68=enum {\nsound/usb/line6/pcm.h:69:\tLINE6_STREAM_PCM,\nsound/usb/line6/pcm.h:70:\tLINE6_STREAM_MONITOR,\nsound/usb/line6/pcm.h:71:\tLINE6_STREAM_IMPULSE,\nsound/usb/line6/pcm.h:72:\tLINE6_STREAM_CAPTURE_HELPER,\nsound/usb/line6/pcm.h-73-};\n--\nsound/usb/line6/pcm.h=76=enum {\nsound/usb/line6/pcm.h:77:\tLINE6_FLAG_PAUSE_PLAYBACK,\nsound/usb/line6/pcm.h:78:\tLINE6_FLAG_PREPARED,\nsound/usb/line6/pcm.h-79-};\n--\nsound/usb/line6/pcm.h=136=struct snd_line6_pcm {\n--\nsound/usb/line6/pcm.h-177-\nsound/usb/line6/pcm.h:178:\t/ Several status bits (see LINE6_FLAG_) /\nsound/usb/line6/pcm.h-179-\tunsigned long flags;\n--\nsound/usb/line6/playback.c=140=static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-151-\t\tline6pcm-\u003eproperties-\u003erates.rats[0].den \nsound/usb/line6/playback.c:152:\t\t(line6pcm-\u003eline6-\u003eintervals_per_second / LINE6_ISO_INTERVAL);\nsound/usb/line6/playback.c-153-\tstruct urb urb_out;\n--\nsound/usb/line6/playback.c-165-\nsound/usb/line6/playback.c:166:\t/ TODO: this may not work for LINE6_ISO_PACKETS != 1 /\nsound/usb/line6/playback.c:167:\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\nsound/usb/line6/playback.c-168-\t\t/ compute frame size for given sampling rate /\n--\nsound/usb/line6/playback.c-199-\t line6pcm-\u003eout.buffer +\nsound/usb/line6/playback.c:200:\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\nsound/usb/line6/playback.c-201-\turb_out-\u003etransfer_buffer_length = urb_size;\n--\nsound/usb/line6/playback.c-203-\nsound/usb/line6/playback.c:204:\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running) \u0026\u0026\nsound/usb/line6/playback.c:205:\t !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags)) {\nsound/usb/line6/playback.c-206-\t\tstruct snd_pcm_runtime runtime =\n--\nsound/usb/line6/playback.c-248-\tif (line6pcm-\u003eprev_fbuf) {\nsound/usb/line6/playback.c:249:\t\tif (test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003eout.running)) {\nsound/usb/line6/playback.c-250-\t\t\tcreate_impulse_test_signal(line6pcm, urb_out,\nsound/usb/line6/playback.c-251-\t\t\t\t\t\t bytes_per_frame);\nsound/usb/line6/playback.c:252:\t\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running)) {\nsound/usb/line6/playback.c-253-\t\t\t\tline6_capture_copy(line6pcm,\n--\nsound/usb/line6/playback.c-260-\t\t} else {\nsound/usb/line6/playback.c:261:\t\t\tif (!(line6pcm-\u003eline6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_HWMON)\nsound/usb/line6/playback.c-262-\t\t\t \u0026\u0026 line6pcm-\u003eout.running \u0026\u0026 line6pcm-\u003ein.running)\n--\nsound/usb/line6/playback.c=303=static void audio_out_callback(struct urb urb)\n--\nsound/usb/line6/playback.c-327-\nsound/usb/line6/playback.c:328:\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; i++)\nsound/usb/line6/playback.c-329-\t\tlength += urb-\u003eiso_frame_desc[i].length;\n--\nsound/usb/line6/playback.c-332-\nsound/usb/line6/playback.c:333:\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running)) {\nsound/usb/line6/playback.c-334-\t\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\n--\nsound/usb/line6/playback.c-344-\nsound/usb/line6/playback.c:345:\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; i++)\nsound/usb/line6/playback.c-346-\t\tif (urb-\u003eiso_frame_desc[i].status == -EXDEV) {\n--\nsound/usb/line6/playback.c-356-\nsound/usb/line6/playback.c:357:\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running)) {\nsound/usb/line6/playback.c-358-\t\t\tline6pcm-\u003eout.bytes += length;\n--\nsound/usb/line6/playback.c=403=int line6_create_audio_out_urbs(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-417-\t\turb = line6pcm-\u003eout.urbs[i] =\nsound/usb/line6/playback.c:418:\t\t usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);\nsound/usb/line6/playback.c-419-\n--\n\n" }
7/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15708 output: 35 thoughts: 23 Thoughts: Here's my take on the thought process: Diving into the Configuration Landscape Okay, so I need to get a handle on the available configuration options and their dependencies for this Line 6 audio device, specifically within the USB and line-in sound setup. The most logical place to start is the `Kconfig` file, located in the relevant sound directory. I'll need to navigate to `sound/usb/line6/Kconfig` to get the complete picture. This should lay out all the settings, dependencies on other modules or kernel features, and the default values if applicable. Knowing the dependencies is crucial; this will help me understand what other pieces I might need to enable or configure in order to have the Line 6 device function as intended. I'm expecting this `Kconfig` file to hold the key.
8/2	2026/09/21 01:50	tool	read-file	0m Args: { "File": "sound/usb/line6/Kconfig", "FirstLine": 1, "LineCount": 60 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\tconfig SND_USB_LINE6\n 3:\t\ttristate\n 4:\t\tselect SND_RAWMIDI\n 5:\t\tselect SND_PCM\n 6:\t\tselect SND_HWDEP\n 7:\t\n 8:\tconfig SND_USB_POD\n 9:\t\ttristate \"Line 6 POD USB support\"\n 10:\t\tselect SND_USB_LINE6\n 11:\t\thelp\n 12:\t\t This is a driver for PODxt and other similar devices,\n 13:\t\t supporting the following features:\n 14:\t\t * Reading/writing individual parameters\n 15:\t\t * Reading/writing complete channel, effects setup, and amp\n 16:\t\t setup data\n 17:\t\t * Channel switching\n 18:\t\t * Virtual MIDI interface\n 19:\t\t * Tuner access\n 20:\t\t * Playback/capture/mixer device for any ALSA-compatible PCM\n 21:\t\t audio application\n 22:\t\t * Signal routing (record clean/processed guitar signal,\n 23:\t\t re-amping)\n 24:\t\n 25:\tconfig SND_USB_PODHD\n 26:\t\ttristate \"Line 6 POD X3/HD300/400/500 USB support\"\n 27:\t\tselect SND_USB_LINE6\n 28:\t\thelp\n 29:\t\t This is a driver for POD X3, HD300, 400 and 500 devices.\n 30:\t\n 31:\tconfig SND_USB_TONEPORT\n 32:\t\ttristate \"TonePort GX, UX1 and UX2 USB support\"\n 33:\t\tselect SND_USB_LINE6\n 34:\t\tselect NEW_LEDS\n 35:\t\tselect LEDS_CLASS\n 36:\t\thelp\n 37:\t\t This is a driver for TonePort GX, UX1 and UX2 devices.\n 38:\t\n 39:\tconfig SND_USB_VARIAX\n 40:\t\ttristate \"Variax Workbench USB support\"\n 41:\t\tselect SND_USB_LINE6\n 42:\t\thelp\n 43:\t\t This is a driver for Variax Workbench device.\n 44:\t\n" }
9/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16529 output: 26 thoughts: 28 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue: Tracing Kconfig Inclusion Alright, I need to figure out the inclusion path for `sound/usb/line6/Kconfig`. It's almost certainly not a standalone Kconfig file, it's a sub-directory, so there must be another Kconfig somewhere, maybe `sound/usb/Kconfig`, that includes it. This is a common pattern in the kernel's Kconfig structure – a parent config file dictates the build rules for the driver(s). Now, time to confirm my educated guess... I'll check `sound/usb/Kconfig` and see if my hunch is correct.
10/2	2026/09/21 01:50	tool	grepper	0m Args: { "Expression": "line6", "PathPrefix": "sound/usb/" } Results: { "Output": "\nFull output is too long, showing 500 out of 2680 lines.\nUse more precise expression if possible.\n\nsound/usb/Kconfig=191=config SND_USB_AUDIO_QMI\n--\nsound/usb/Kconfig-206-\nsound/usb/Kconfig:207:source \"sound/usb/line6/Kconfig\"\nsound/usb/Kconfig-208-\n--\nsound/usb/Makefile=38=obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/ qcom/\nsound/usb/Makefile:39:obj-$(CONFIG_SND_USB_LINE6)\t+= line6/\n--\nsound/usb/format.c=421=static int parse_uac2_sample_rate_range(struct snd_usb_audio chip,\n--\nsound/usb/format.c-489- /\nsound/usb/format.c:490:static int line6_parse_audio_format_rates_quirk(struct snd_usb_audio chip,\nsound/usb/format.c-491-\t\t\t\t\t\tstruct audioformat fp)\n--\nsound/usb/format.c=621=static int parse_audio_format_rates_v2v3(struct snd_usb_audio chip,\n--\nsound/usb/format.c-645-\tif (ret \u003c 0) {\nsound/usb/format.c:646:\t\t/ line6 helix devices don't support UAC2_CS_CONTROL_SAM_FREQ call /\nsound/usb/format.c:647:\t\tret_l6 = line6_parse_audio_format_rates_quirk(chip, fp);\nsound/usb/format.c-648-\t\tif (ret_l6 == -ENODEV) {\nsound/usb/format.c:649:\t\t\t/ no line6 device found continue showing the error /\nsound/usb/format.c-650-\t\t\tdev_err(\u0026dev-\u003edev,\n--\nsound/usb/line6/Makefile-1-# SPDX-License-Identifier: GPL-2.0\nsound/usb/line6/Makefile:2:snd-usb-line6-y := \t\t\\\nsound/usb/line6/Makefile-3-\t\tcapture.o\t\\\n--\nsound/usb/line6/Makefile=13=snd-usb-variax-y := variax.o\nsound/usb/line6/Makefile-14-\nsound/usb/line6/Makefile:15:obj-$(CONFIG_SND_USB_LINE6)\t+= snd-usb-line6.o\nsound/usb/line6/Makefile-16-obj-$(CONFIG_SND_USB_POD)\t+= snd-usb-pod.o\n--\nsound/usb/line6/capture.c-4- \nsound/usb/line6/capture.c:5: * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)\nsound/usb/line6/capture.c-6- /\n--\nsound/usb/line6/capture.c-18-\tFind a free URB and submit it.\nsound/usb/line6/capture.c:19:\tmust be called in line6pcm-\u003ein.lock context\nsound/usb/line6/capture.c-20-/\nsound/usb/line6/capture.c:21:static int submit_audio_in_urb(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-22-{\n--\nsound/usb/line6/capture.c-27-\nsound/usb/line6/capture.c:28:\tindex = find_first_zero_bit(\u0026line6pcm-\u003ein.active_urbs,\nsound/usb/line6/capture.c:29:\t\t\t\t line6pcm-\u003eline6-\u003eiso_buffers);\nsound/usb/line6/capture.c-30-\nsound/usb/line6/capture.c:31:\tif (index \u003c 0 \|\| index \u003e= line6pcm-\u003eline6-\u003eiso_buffers) {\nsound/usb/line6/capture.c:32:\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"no free URB found\\n\");\nsound/usb/line6/capture.c-33-\t\treturn -EINVAL;\n--\nsound/usb/line6/capture.c-35-\nsound/usb/line6/capture.c:36:\turb_in = line6pcm-\u003ein.urbs[index];\nsound/usb/line6/capture.c-37-\turb_size = 0;\n--\nsound/usb/line6/capture.c-42-\t\tfin-\u003eoffset = urb_size;\nsound/usb/line6/capture.c:43:\t\tfin-\u003elength = line6pcm-\u003emax_packet_size_in;\nsound/usb/line6/capture.c:44:\t\turb_size += line6pcm-\u003emax_packet_size_in;\nsound/usb/line6/capture.c-45-\t}\n--\nsound/usb/line6/capture.c-47-\turb_in-\u003etransfer_buffer =\nsound/usb/line6/capture.c:48:\t line6pcm-\u003ein.buffer +\nsound/usb/line6/capture.c:49:\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_in;\nsound/usb/line6/capture.c-50-\turb_in-\u003etransfer_buffer_length = urb_size;\nsound/usb/line6/capture.c:51:\turb_in-\u003econtext = line6pcm;\nsound/usb/line6/capture.c-52-\n--\nsound/usb/line6/capture.c-55-\tif (ret == 0)\nsound/usb/line6/capture.c:56:\t\tset_bit(index, \u0026line6pcm-\u003ein.active_urbs);\nsound/usb/line6/capture.c-57-\telse\nsound/usb/line6/capture.c:58:\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev,\nsound/usb/line6/capture.c-59-\t\t\t\"URB in #%d submission failed (%d)\\n\", index, ret);\n--\nsound/usb/line6/capture.c-65-\tSubmit all currently available capture URBs.\nsound/usb/line6/capture.c:66:\tmust be called in line6pcm-\u003ein.lock context\nsound/usb/line6/capture.c-67-/\nsound/usb/line6/capture.c:68:int line6_submit_audio_in_all_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-69-{\n--\nsound/usb/line6/capture.c-71-\nsound/usb/line6/capture.c:72:\tfor (i = 0; i \u003c line6pcm-\u003eline6-\u003eiso_buffers; ++i) {\nsound/usb/line6/capture.c:73:\t\tret = submit_audio_in_urb(line6pcm);\nsound/usb/line6/capture.c-74-\t\tif (ret \u003c 0)\n--\nsound/usb/line6/capture.c-83-/\nsound/usb/line6/capture.c:84:void line6_capture_copy(struct snd_line6_pcm line6pcm, char fbuf, int fsize)\nsound/usb/line6/capture.c-85-{\nsound/usb/line6/capture.c-86-\tstruct snd_pcm_substream substream =\nsound/usb/line6/capture.c:87:\t get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE);\nsound/usb/line6/capture.c-88-\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\nsound/usb/line6/capture.c-89-\tconst int bytes_per_frame =\nsound/usb/line6/capture.c:90:\t\tline6pcm-\u003eproperties-\u003ebytes_per_channel \nsound/usb/line6/capture.c:91:\t\tline6pcm-\u003eproperties-\u003ecapture_hw.channels_max;\nsound/usb/line6/capture.c-92-\tint frames = fsize / bytes_per_frame;\n--\nsound/usb/line6/capture.c-96-\nsound/usb/line6/capture.c:97:\tif (line6pcm-\u003ein.pos_done + frames \u003e runtime-\u003ebuffer_size) {\nsound/usb/line6/capture.c-98-\t\t/\n--\nsound/usb/line6/capture.c-103-\nsound/usb/line6/capture.c:104:\t\tlen = runtime-\u003ebuffer_size - line6pcm-\u003ein.pos_done;\nsound/usb/line6/capture.c-105-\n--\nsound/usb/line6/capture.c-107-\t\t\tmemcpy(runtime-\u003edma_area +\nsound/usb/line6/capture.c:108:\t\t\t line6pcm-\u003ein.pos_done bytes_per_frame, fbuf,\nsound/usb/line6/capture.c-109-\t\t\t len * bytes_per_frame);\n--\nsound/usb/line6/capture.c-113-\t\t\t/* this is somewhat paranoid /\nsound/usb/line6/capture.c:114:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev,\nsound/usb/line6/capture.c-115-\t\t\t\t\"driver bug: len = %d\\n\", len);\n--\nsound/usb/line6/capture.c-119-\t\tmemcpy(runtime-\u003edma_area +\nsound/usb/line6/capture.c:120:\t\t line6pcm-\u003ein.pos_done bytes_per_frame, fbuf, fsize);\nsound/usb/line6/capture.c-121-\t}\nsound/usb/line6/capture.c-122-\nsound/usb/line6/capture.c:123:\tline6pcm-\u003ein.pos_done += frames;\nsound/usb/line6/capture.c:124:\tif (line6pcm-\u003ein.pos_done \u003e= runtime-\u003ebuffer_size)\nsound/usb/line6/capture.c:125:\t\tline6pcm-\u003ein.pos_done -= runtime-\u003ebuffer_size;\nsound/usb/line6/capture.c-126-}\nsound/usb/line6/capture.c-127-\nsound/usb/line6/capture.c:128:void line6_capture_check_period(struct snd_line6_pcm line6pcm, int length)\nsound/usb/line6/capture.c-129-{\nsound/usb/line6/capture.c-130-\tstruct snd_pcm_substream substream =\nsound/usb/line6/capture.c:131:\t get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE);\nsound/usb/line6/capture.c-132-\nsound/usb/line6/capture.c:133:\tline6pcm-\u003ein.bytes += length;\nsound/usb/line6/capture.c:134:\tif (line6pcm-\u003ein.bytes \u003e= line6pcm-\u003ein.period) {\nsound/usb/line6/capture.c:135:\t\tline6pcm-\u003ein.bytes %= line6pcm-\u003ein.period;\nsound/usb/line6/capture.c:136:\t\tspin_unlock(\u0026line6pcm-\u003ein.lock);\nsound/usb/line6/capture.c-137-\t\tsnd_pcm_period_elapsed(substream);\nsound/usb/line6/capture.c:138:\t\tspin_lock(\u0026line6pcm-\u003ein.lock);\nsound/usb/line6/capture.c-139-\t}\n--\nsound/usb/line6/capture.c=145=static void audio_in_callback(struct urb urb)\n--\nsound/usb/line6/capture.c-147-\tint i, index, length = 0, shutdown = 0;\nsound/usb/line6/capture.c:148:\tstruct snd_line6_pcm line6pcm = (struct snd_line6_pcm )urb-\u003econtext;\nsound/usb/line6/capture.c-149-\nsound/usb/line6/capture.c:150:\tline6pcm-\u003ein.last_frame = urb-\u003estart_frame;\nsound/usb/line6/capture.c-151-\nsound/usb/line6/capture.c-152-\t/ find index of URB /\nsound/usb/line6/capture.c:153:\tfor (index = 0; index \u003c line6pcm-\u003eline6-\u003eiso_buffers; ++index)\nsound/usb/line6/capture.c:154:\t\tif (urb == line6pcm-\u003ein.urbs[index])\nsound/usb/line6/capture.c-155-\t\t\tbreak;\nsound/usb/line6/capture.c-156-\nsound/usb/line6/capture.c:157:\tguard(spinlock_irqsave)(\u0026line6pcm-\u003ein.lock);\nsound/usb/line6/capture.c-158-\n--\nsound/usb/line6/capture.c-171-\nsound/usb/line6/capture.c:172:\t\tif (fsize \u003e line6pcm-\u003emax_packet_size_in) {\nsound/usb/line6/capture.c:173:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev,\nsound/usb/line6/capture.c-174-\t\t\t\t\"driver and/or device bug: packet too large (%d \u003e %d)\\n\",\nsound/usb/line6/capture.c:175:\t\t\t\tfsize, line6pcm-\u003emax_packet_size_in);\nsound/usb/line6/capture.c-176-\t\t}\n--\nsound/usb/line6/capture.c-188-\nsound/usb/line6/capture.c:189:\t\tline6pcm-\u003eprev_fbuf = fbuf;\nsound/usb/line6/capture.c:190:\t\tline6pcm-\u003eprev_fsize = fsize /\nsound/usb/line6/capture.c:191:\t\t\t(line6pcm-\u003eproperties-\u003ebytes_per_channel \nsound/usb/line6/capture.c:192:\t\t\tline6pcm-\u003eproperties-\u003ecapture_hw.channels_max);\nsound/usb/line6/capture.c-193-\nsound/usb/line6/capture.c:194:\t\tif (!test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c:195:\t\t test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c-196-\t\t fsize \u003e 0)\nsound/usb/line6/capture.c:197:\t\t\tline6_capture_copy(line6pcm, fbuf, fsize);\nsound/usb/line6/capture.c-198-\t}\nsound/usb/line6/capture.c-199-\nsound/usb/line6/capture.c:200:\tclear_bit(index, \u0026line6pcm-\u003ein.active_urbs);\nsound/usb/line6/capture.c-201-\nsound/usb/line6/capture.c:202:\tif (test_and_clear_bit(index, \u0026line6pcm-\u003ein.unlink_urbs))\nsound/usb/line6/capture.c-203-\t\tshutdown = 1;\n--\nsound/usb/line6/capture.c-205-\tif (!shutdown) {\nsound/usb/line6/capture.c:206:\t\tsubmit_audio_in_urb(line6pcm);\nsound/usb/line6/capture.c-207-\nsound/usb/line6/capture.c:208:\t\tif (!test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003ein.running) \u0026\u0026\nsound/usb/line6/capture.c:209:\t\t test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running))\nsound/usb/line6/capture.c:210:\t\t\tline6_capture_check_period(line6pcm, length);\nsound/usb/line6/capture.c-211-\t}\n--\nsound/usb/line6/capture.c-214-/* open capture callback /\nsound/usb/line6/capture.c:215:static int snd_line6_capture_open(struct snd_pcm_substream substream)\nsound/usb/line6/capture.c-216-{\n--\nsound/usb/line6/capture.c-218-\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\nsound/usb/line6/capture.c:219:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/capture.c-220-\n--\nsound/usb/line6/capture.c-222-\t\t\t\t\t SNDRV_PCM_HW_PARAM_RATE,\nsound/usb/line6/capture.c:223:\t\t\t\t\t \u0026line6pcm-\u003eproperties-\u003erates);\nsound/usb/line6/capture.c-224-\tif (err \u003c 0)\n--\nsound/usb/line6/capture.c-226-\nsound/usb/line6/capture.c:227:\tline6_pcm_acquire(line6pcm, LINE6_STREAM_CAPTURE_HELPER, false);\nsound/usb/line6/capture.c-228-\nsound/usb/line6/capture.c:229:\truntime-\u003ehw = line6pcm-\u003eproperties-\u003ecapture_hw;\nsound/usb/line6/capture.c-230-\treturn 0;\n--\nsound/usb/line6/capture.c-233-/* close capture callback /\nsound/usb/line6/capture.c:234:static int snd_line6_capture_close(struct snd_pcm_substream substream)\nsound/usb/line6/capture.c-235-{\nsound/usb/line6/capture.c:236:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/capture.c-237-\nsound/usb/line6/capture.c:238:\tline6_pcm_release(line6pcm, LINE6_STREAM_CAPTURE_HELPER);\nsound/usb/line6/capture.c-239-\treturn 0;\n--\nsound/usb/line6/capture.c-242-/ capture operators /\nsound/usb/line6/capture.c:243:const struct snd_pcm_ops snd_line6_capture_ops = {\nsound/usb/line6/capture.c:244:\t.open = snd_line6_capture_open,\nsound/usb/line6/capture.c:245:\t.close = snd_line6_capture_close,\nsound/usb/line6/capture.c:246:\t.hw_params = snd_line6_hw_params,\nsound/usb/line6/capture.c:247:\t.hw_free = snd_line6_hw_free,\nsound/usb/line6/capture.c:248:\t.prepare = snd_line6_prepare,\nsound/usb/line6/capture.c:249:\t.trigger = snd_line6_trigger,\nsound/usb/line6/capture.c:250:\t.pointer = snd_line6_pointer,\nsound/usb/line6/capture.c-251-};\nsound/usb/line6/capture.c-252-\nsound/usb/line6/capture.c:253:int line6_create_audio_in_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-254-{\nsound/usb/line6/capture.c:255:\tstruct usb_line6 line6 = line6pcm-\u003eline6;\nsound/usb/line6/capture.c-256-\tint i;\nsound/usb/line6/capture.c-257-\nsound/usb/line6/capture.c:258:\tline6pcm-\u003ein.urbs = kzalloc_objs(struct urb , line6-\u003eiso_buffers);\nsound/usb/line6/capture.c:259:\tif (line6pcm-\u003ein.urbs == NULL)\nsound/usb/line6/capture.c-260-\t\treturn -ENOMEM;\n--\nsound/usb/line6/capture.c-262-\t/* create audio URBs and fill in constant values: /\nsound/usb/line6/capture.c:263:\tfor (i = 0; i \u003c line6-\u003eiso_buffers; ++i) {\nsound/usb/line6/capture.c-264-\t\tstruct urb urb;\n--\nsound/usb/line6/capture.c-266-\t\t/* URB for audio in: /\nsound/usb/line6/capture.c:267:\t\turb = line6pcm-\u003ein.urbs[i] =\nsound/usb/line6/capture.c-268-\t\t usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);\n--\nsound/usb/line6/capture.c-272-\nsound/usb/line6/capture.c:273:\t\turb-\u003edev = line6-\u003eusbdev;\nsound/usb/line6/capture.c-274-\t\turb-\u003epipe =\nsound/usb/line6/capture.c:275:\t\t usb_rcvisocpipe(line6-\u003eusbdev,\nsound/usb/line6/capture.c:276:\t\t\t\t line6-\u003eproperties-\u003eep_audio_r \u0026\nsound/usb/line6/capture.c-277-\t\t\t\t USB_ENDPOINT_NUMBER_MASK);\n--\nsound/usb/line6/capture.h-4- \nsound/usb/line6/capture.h:5: * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)\nsound/usb/line6/capture.h-6- /\n--\nsound/usb/line6/capture.h-15-\nsound/usb/line6/capture.h:16:extern const struct snd_pcm_ops snd_line6_capture_ops;\nsound/usb/line6/capture.h-17-\nsound/usb/line6/capture.h:18:extern void line6_capture_copy(struct snd_line6_pcm line6pcm, char fbuf,\nsound/usb/line6/capture.h-19-\t\t\t int fsize);\nsound/usb/line6/capture.h:20:extern void line6_capture_check_period(struct snd_line6_pcm line6pcm,\nsound/usb/line6/capture.h-21-\t\t\t\t int length);\nsound/usb/line6/capture.h:22:extern int line6_create_audio_in_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/capture.h:23:extern int line6_submit_audio_in_all_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/capture.h-24-\n--\nsound/usb/line6/driver.c-4- \nsound/usb/line6/driver.c:5: Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)\nsound/usb/line6/driver.c-6- /\n--\nsound/usb/line6/driver.c-22-\nsound/usb/line6/driver.c:23:#define DRIVER_AUTHOR \"Markus Grabner \u003cline6@grabner-graz.at\u003e\"\nsound/usb/line6/driver.c-24-#define DRIVER_DESC \"Line 6 USB Driver\"\n--\nsound/usb/line6/driver.c-28-/\nsound/usb/line6/driver.c:29:const unsigned char line6_midi_id[3] = {\nsound/usb/line6/driver.c-30-\t0x00, 0x01, 0x0c\nsound/usb/line6/driver.c-31-};\nsound/usb/line6/driver.c:32:EXPORT_SYMBOL_GPL(line6_midi_id);\nsound/usb/line6/driver.c-33-\n--\nsound/usb/line6/driver.c-37-/\nsound/usb/line6/driver.c:38:static const char line6_request_version[] = {\nsound/usb/line6/driver.c-39-\t0xf0, 0x7e, 0x7f, 0x06, 0x01, 0xf7\n--\nsound/usb/line6/driver.c=45=struct message {\nsound/usb/line6/driver.c:46:\tstruct usb_line6 line6;\nsound/usb/line6/driver.c-47-\tconst char buffer;\n--\nsound/usb/line6/driver.c-54-/\nsound/usb/line6/driver.c:55:static void line6_data_received(struct urb urb);\nsound/usb/line6/driver.c:56:static int line6_send_raw_message_async_part(struct message msg,\nsound/usb/line6/driver.c-57-\t\t\t\t\t struct urb urb);\n--\nsound/usb/line6/driver.c-61-/\nsound/usb/line6/driver.c:62:static int line6_start_listen(struct usb_line6 line6)\nsound/usb/line6/driver.c-63-{\n--\nsound/usb/line6/driver.c-65-\nsound/usb/line6/driver.c:66:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c:67:\t\tusb_fill_int_urb(line6-\u003eurb_listen, line6-\u003eusbdev,\nsound/usb/line6/driver.c:68:\t\t\tusb_rcvintpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_r),\nsound/usb/line6/driver.c:69:\t\t\tline6-\u003ebuffer_listen, LINE6_BUFSIZE_LISTEN,\nsound/usb/line6/driver.c:70:\t\t\tline6_data_received, line6, line6-\u003einterval);\nsound/usb/line6/driver.c-71-\t} else {\nsound/usb/line6/driver.c:72:\t\tusb_fill_bulk_urb(line6-\u003eurb_listen, line6-\u003eusbdev,\nsound/usb/line6/driver.c:73:\t\t\tusb_rcvbulkpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_r),\nsound/usb/line6/driver.c:74:\t\t\tline6-\u003ebuffer_listen, LINE6_BUFSIZE_LISTEN,\nsound/usb/line6/driver.c:75:\t\t\tline6_data_received, line6);\nsound/usb/line6/driver.c-76-\t}\n--\nsound/usb/line6/driver.c-78-\t/ sanity checks of EP before actually submitting /\nsound/usb/line6/driver.c:79:\tif (usb_urb_ep_type_check(line6-\u003eurb_listen)) {\nsound/usb/line6/driver.c:80:\t\tdev_err(line6-\u003eifcdev, \"invalid control EP\\n\");\nsound/usb/line6/driver.c-81-\t\treturn -EINVAL;\n--\nsound/usb/line6/driver.c-83-\nsound/usb/line6/driver.c:84:\tline6-\u003eurb_listen-\u003eactual_length = 0;\nsound/usb/line6/driver.c:85:\terr = usb_submit_urb(line6-\u003eurb_listen, GFP_ATOMIC);\nsound/usb/line6/driver.c-86-\treturn err;\n--\nsound/usb/line6/driver.c-91-/\nsound/usb/line6/driver.c:92:static void line6_stop_listen(struct usb_line6 line6)\nsound/usb/line6/driver.c-93-{\nsound/usb/line6/driver.c:94:\tusb_kill_urb(line6-\u003eurb_listen);\nsound/usb/line6/driver.c-95-}\n--\nsound/usb/line6/driver.c-99-/\nsound/usb/line6/driver.c:100:int line6_send_raw_message(struct usb_line6 line6, const char buffer,\nsound/usb/line6/driver.c-101-\t\t\t\t int size)\n--\nsound/usb/line6/driver.c-103-\tint i, done = 0;\nsound/usb/line6/driver.c:104:\tconst struct line6_properties properties = line6-\u003eproperties;\nsound/usb/line6/driver.c-105-\nsound/usb/line6/driver.c:106:\tfor (i = 0; i \u003c size; i += line6-\u003emax_packet_size) {\nsound/usb/line6/driver.c-107-\t\tint partial;\nsound/usb/line6/driver.c-108-\t\tconst char frag_buf = buffer + i;\nsound/usb/line6/driver.c:109:\t\tint frag_size = min(line6-\u003emax_packet_size, size - i);\nsound/usb/line6/driver.c-110-\t\tint retval;\n--\nsound/usb/line6/driver.c-112-\t\tif (properties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c:113:\t\t\tretval = usb_interrupt_msg(line6-\u003eusbdev,\nsound/usb/line6/driver.c:114:\t\t\t\t\t\tusb_sndintpipe(line6-\u003eusbdev, properties-\u003eep_ctrl_w),\nsound/usb/line6/driver.c-115-\t\t\t\t\t\t(char )frag_buf, frag_size,\n--\nsound/usb/line6/driver.c-117-\t\t} else {\nsound/usb/line6/driver.c:118:\t\t\tretval = usb_bulk_msg(line6-\u003eusbdev,\nsound/usb/line6/driver.c:119:\t\t\t\t\t\tusb_sndbulkpipe(line6-\u003eusbdev, properties-\u003eep_ctrl_w),\nsound/usb/line6/driver.c-120-\t\t\t\t\t\t(char )frag_buf, frag_size,\n--\nsound/usb/line6/driver.c-124-\t\tif (retval) {\nsound/usb/line6/driver.c:125:\t\t\tdev_err(line6-\u003eifcdev,\nsound/usb/line6/driver.c-126-\t\t\t\t\"usb_bulk_msg failed (%d)\\n\", retval);\n--\nsound/usb/line6/driver.c-134-}\nsound/usb/line6/driver.c:135:EXPORT_SYMBOL_GPL(line6_send_raw_message);\nsound/usb/line6/driver.c-136-\n--\nsound/usb/line6/driver.c-139-/\nsound/usb/line6/driver.c:140:static void line6_async_request_sent(struct urb urb)\nsound/usb/line6/driver.c-141-{\n--\nsound/usb/line6/driver.c-147-\t} else\nsound/usb/line6/driver.c:148:\t\tline6_send_raw_message_async_part(msg, urb);\nsound/usb/line6/driver.c-149-}\n--\nsound/usb/line6/driver.c-153-/\nsound/usb/line6/driver.c:154:static int line6_send_raw_message_async_part(struct message msg,\nsound/usb/line6/driver.c-155-\t\t\t\t\t struct urb urb)\n--\nsound/usb/line6/driver.c-157-\tint retval;\nsound/usb/line6/driver.c:158:\tstruct usb_line6 line6 = msg-\u003eline6;\nsound/usb/line6/driver.c-159-\tint done = msg-\u003edone;\nsound/usb/line6/driver.c:160:\tint bytes = min(msg-\u003esize - done, line6-\u003emax_packet_size);\nsound/usb/line6/driver.c-161-\nsound/usb/line6/driver.c:162:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c:163:\t\tusb_fill_int_urb(urb, line6-\u003eusbdev,\nsound/usb/line6/driver.c:164:\t\t\tusb_sndintpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_w),\nsound/usb/line6/driver.c-165-\t\t\t(char )msg-\u003ebuffer + done, bytes,\nsound/usb/line6/driver.c:166:\t\t\tline6_async_request_sent, msg, line6-\u003einterval);\nsound/usb/line6/driver.c-167-\t} else {\nsound/usb/line6/driver.c:168:\t\tusb_fill_bulk_urb(urb, line6-\u003eusbdev,\nsound/usb/line6/driver.c:169:\t\t\tusb_sndbulkpipe(line6-\u003eusbdev, line6-\u003eproperties-\u003eep_ctrl_w),\nsound/usb/line6/driver.c-170-\t\t\t(char )msg-\u003ebuffer + done, bytes,\nsound/usb/line6/driver.c:171:\t\t\tline6_async_request_sent, msg);\nsound/usb/line6/driver.c-172-\t}\n--\nsound/usb/line6/driver.c-187- error:\nsound/usb/line6/driver.c:188:\tdev_err(line6-\u003eifcdev, \"%s: usb_submit_urb failed (%d)\\n\",\nsound/usb/line6/driver.c-189-\t\t__func__, retval);\n--\nsound/usb/line6/driver.c-197-/\nsound/usb/line6/driver.c:198:int line6_send_raw_message_async(struct usb_line6 line6, const char buffer,\nsound/usb/line6/driver.c-199-\t\t\t\t int size)\n--\nsound/usb/line6/driver.c-217-\t/ set message data: /\nsound/usb/line6/driver.c:218:\tmsg-\u003eline6 = line6;\nsound/usb/line6/driver.c-219-\tmsg-\u003ebuffer = buffer;\n--\nsound/usb/line6/driver.c-223-\t/ start sending: /\nsound/usb/line6/driver.c:224:\treturn line6_send_raw_message_async_part(msg, urb);\nsound/usb/line6/driver.c-225-}\nsound/usb/line6/driver.c:226:EXPORT_SYMBOL_GPL(line6_send_raw_message_async);\nsound/usb/line6/driver.c-227-\n--\nsound/usb/line6/driver.c-230-/\nsound/usb/line6/driver.c:231:int line6_version_request_async(struct usb_line6 line6)\nsound/usb/line6/driver.c-232-{\n--\nsound/usb/line6/driver.c-235-\nsound/usb/line6/driver.c:236:\tbuffer = kmemdup(line6_request_version,\nsound/usb/line6/driver.c:237:\t\t\tsizeof(line6_request_version), GFP_ATOMIC);\nsound/usb/line6/driver.c-238-\tif (buffer == NULL)\n--\nsound/usb/line6/driver.c-240-\nsound/usb/line6/driver.c:241:\tretval = line6_send_raw_message_async(line6, buffer,\nsound/usb/line6/driver.c:242:\t\t\t\t\t sizeof(line6_request_version));\nsound/usb/line6/driver.c-243-\tkfree(buffer);\n--\nsound/usb/line6/driver.c-245-}\nsound/usb/line6/driver.c:246:EXPORT_SYMBOL_GPL(line6_version_request_async);\nsound/usb/line6/driver.c-247-\n--\nsound/usb/line6/driver.c-250-/\nsound/usb/line6/driver.c:251:int line6_send_sysex_message(struct usb_line6 line6, const char buffer,\nsound/usb/line6/driver.c-252-\t\t\t int size)\nsound/usb/line6/driver.c-253-{\nsound/usb/line6/driver.c:254:\treturn line6_send_raw_message(line6, buffer,\nsound/usb/line6/driver.c-255-\t\t\t\t size + SYSEX_EXTRA_SIZE) -\n--\nsound/usb/line6/driver.c-257-}\nsound/usb/line6/driver.c:258:EXPORT_SYMBOL_GPL(line6_send_sysex_message);\nsound/usb/line6/driver.c-259-\n--\nsound/usb/line6/driver.c-264-/\nsound/usb/line6/driver.c:265:char line6_alloc_sysex_buffer(struct usb_line6 line6, int code1, int code2,\nsound/usb/line6/driver.c-266-\t\t\t int size)\n--\nsound/usb/line6/driver.c-273-\tbuffer[0] = LINE6_SYSEX_BEGIN;\nsound/usb/line6/driver.c:274:\tmemcpy(buffer + 1, line6_midi_id, sizeof(line6_midi_id));\nsound/usb/line6/driver.c:275:\tbuffer[sizeof(line6_midi_id) + 1] = code1;\nsound/usb/line6/driver.c:276:\tbuffer[sizeof(line6_midi_id) + 2] = code2;\nsound/usb/line6/driver.c:277:\tbuffer[sizeof(line6_midi_id) + 3 + size] = LINE6_SYSEX_END;\nsound/usb/line6/driver.c-278-\treturn buffer;\nsound/usb/line6/driver.c-279-}\nsound/usb/line6/driver.c:280:EXPORT_SYMBOL_GPL(line6_alloc_sysex_buffer);\nsound/usb/line6/driver.c-281-\n--\nsound/usb/line6/driver.c-284-/\nsound/usb/line6/driver.c:285:static void line6_data_received(struct urb urb)\nsound/usb/line6/driver.c-286-{\nsound/usb/line6/driver.c:287:\tstruct usb_line6 line6 = (struct usb_line6 )urb-\u003econtext;\nsound/usb/line6/driver.c:288:\tstruct midi_buffer mb = \u0026line6-\u003eline6midi-\u003emidibuf_in;\nsound/usb/line6/driver.c-289-\tint done;\n--\nsound/usb/line6/driver.c-293-\nsound/usb/line6/driver.c:294:\tif (line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_CONTROL_MIDI) {\nsound/usb/line6/driver.c:295:\t\tscoped_guard(spinlock_irqsave, \u0026line6-\u003eline6midi-\u003elock) {\nsound/usb/line6/driver.c-296-\t\t\tdone =\nsound/usb/line6/driver.c:297:\t\t\t\tline6_midibuf_write(mb, urb-\u003etransfer_buffer, urb-\u003eactual_length);\nsound/usb/line6/driver.c-298-\nsound/usb/line6/driver.c-299-\t\t\tif (done \u003c urb-\u003eactual_length) {\nsound/usb/line6/driver.c:300:\t\t\t\tline6_midibuf_ignore(mb, done);\nsound/usb/line6/driver.c:301:\t\t\t\tdev_dbg(line6-\u003eifcdev, \"%d %d buffer overflow - message skipped\\n\",\nsound/usb/line6/driver.c-302-\t\t\t\t\tdone, urb-\u003eactual_length);\n--\nsound/usb/line6/driver.c-306-\t\tfor (;;) {\nsound/usb/line6/driver.c:307:\t\t\tscoped_guard(spinlock_irqsave, \u0026line6-\u003eline6midi-\u003elock) {\nsound/usb/line6/driver.c-308-\t\t\t\tdone =\nsound/usb/line6/driver.c:309:\t\t\t\t\tline6_midibuf_read(mb, line6-\u003ebuffer_message,\nsound/usb/line6/driver.c-310-\t\t\t\t\t\t\t LINE6_MIDI_MESSAGE_MAXLEN,\n--\nsound/usb/line6/driver.c-316-\nsound/usb/line6/driver.c:317:\t\t\tline6-\u003emessage_length = done;\nsound/usb/line6/driver.c:318:\t\t\tline6_midi_receive(line6, line6-\u003ebuffer_message, done);\nsound/usb/line6/driver.c-319-\nsound/usb/line6/driver.c:320:\t\t\tif (line6-\u003eprocess_message)\nsound/usb/line6/driver.c:321:\t\t\t\tline6-\u003eprocess_message(line6);\nsound/usb/line6/driver.c-322-\t\t}\nsound/usb/line6/driver.c-323-\t} else {\nsound/usb/line6/driver.c:324:\t\tline6-\u003ebuffer_message = urb-\u003etransfer_buffer;\nsound/usb/line6/driver.c:325:\t\tline6-\u003emessage_length = urb-\u003eactual_length;\nsound/usb/line6/driver.c:326:\t\tif (line6-\u003eprocess_message)\nsound/usb/line6/driver.c:327:\t\t\tline6-\u003eprocess_message(line6);\nsound/usb/line6/driver.c:328:\t\tline6-\u003ebuffer_message = NULL;\nsound/usb/line6/driver.c-329-\t}\nsound/usb/line6/driver.c-330-\nsound/usb/line6/driver.c:331:\tline6_start_listen(line6);\nsound/usb/line6/driver.c-332-}\n--\nsound/usb/line6/driver.c-339-/\nsound/usb/line6/driver.c:340:int line6_read_data(struct usb_line6 line6, unsigned address, void data,\nsound/usb/line6/driver.c-341-\t\t unsigned datalen)\nsound/usb/line6/driver.c-342-{\nsound/usb/line6/driver.c:343:\tstruct usb_device usbdev = line6-\u003eusbdev;\nsound/usb/line6/driver.c-344-\tint ret;\n--\nsound/usb/line6/driver.c-356-\tif (ret) {\nsound/usb/line6/driver.c:357:\t\tdev_err(line6-\u003eifcdev, \"read request failed (error %d)\\n\", ret);\nsound/usb/line6/driver.c-358-\t\tgoto exit;\n--\nsound/usb/line6/driver.c-369-\t\tif (ret) {\nsound/usb/line6/driver.c:370:\t\t\tdev_err(line6-\u003eifcdev,\nsound/usb/line6/driver.c-371-\t\t\t\t\"receive length failed (error %d)\\n\", ret);\n--\nsound/usb/line6/driver.c-380-\tif (len == 0xff) {\nsound/usb/line6/driver.c:381:\t\tdev_err(line6-\u003eifcdev, \"read failed after %d retries\\n\",\nsound/usb/line6/driver.c-382-\t\t\tcount);\n--\nsound/usb/line6/driver.c-385-\t\t/* should be equal or something went wrong */\n\n" }
11/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 28007 output: 38 thoughts: 418 Thoughts: Analyzing the Commit and Code Change Okay, let's dive into this. I need to understand what this commit is doing. My initial instinct is to check the `git log` to get a quick overview with something like `git log -1` but I don't have that tool available, I see I only have `read-file`, `grepper`, `codesearch-dir-index`, and `set-results`. Since I'm presented with the commit message and the diff, I can use that and the other tools. The user has given me the commit details: commit hash, author, date, and message: "syz-cluster: applied patch under review". That's a helpful starting point, although not super descriptive. The diff is what's really interesting here. I can see a change within the `sound/usb/line6/playback.c` file. Specifically, a new line was added within the `submit_audio_out_urb` function to restrict `fsize` (frame size) with the `min` function and `line6pcm->max_packet_size_out`. Given that I don't have the standard `git` tools, I should now read `sound/usb/line6/playback.c` to understand the context of this change in more detail. That will give me a better understanding of why they are limiting the `fsize`.
12/2	2026/09/21 01:50	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 140, "LineCount": 80 } Results: { "Contents": " 140:\tstatic int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n 141:\t{\n 142:\t\tint index;\n 143:\t\tint i, urb_size, urb_frames;\n 144:\t\tint ret;\n 145:\t\tconst int bytes_per_frame =\n 146:\t\t\tline6pcm-\u003eproperties-\u003ebytes_per_channel \n 147:\t\t\tline6pcm-\u003eproperties-\u003eplayback_hw.channels_max;\n 148:\t\tconst int frame_increment =\n 149:\t\t\tline6pcm-\u003eproperties-\u003erates.rats[0].num_min;\n 150:\t\tconst int frame_factor =\n 151:\t\t\tline6pcm-\u003eproperties-\u003erates.rats[0].den \n 152:\t\t\t(line6pcm-\u003eline6-\u003eintervals_per_second / LINE6_ISO_INTERVAL);\n 153:\t\tstruct urb urb_out;\n 154:\t\n 155:\t\tindex = find_first_zero_bit(\u0026line6pcm-\u003eout.active_urbs,\n 156:\t\t\t\t\t line6pcm-\u003eline6-\u003eiso_buffers);\n 157:\t\n 158:\t\tif (index \u003c 0 \|\| index \u003e= line6pcm-\u003eline6-\u003eiso_buffers) {\n 159:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"no free URB found\\n\");\n 160:\t\t\treturn -EINVAL;\n 161:\t\t}\n 162:\t\n 163:\t\turb_out = line6pcm-\u003eout.urbs[index];\n 164:\t\turb_size = 0;\n 165:\t\n 166:\t\t/* TODO: this may not work for LINE6_ISO_PACKETS != 1 /\n 167:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\n 168:\t\t\t/ compute frame size for given sampling rate /\n 169:\t\t\tint fsize = 0;\n 170:\t\t\tstruct usb_iso_packet_descriptor fout =\n 171:\t\t\t \u0026urb_out-\u003eiso_frame_desc[i];\n 172:\t\n 173:\t\t\tfsize = line6pcm-\u003eprev_fsize;\n 174:\t\t\tif (fsize == 0) {\n 175:\t\t\t\tint n;\n 176:\t\n 177:\t\t\t\tline6pcm-\u003eout.count += frame_increment;\n 178:\t\t\t\tn = line6pcm-\u003eout.count / frame_factor;\n 179:\t\t\t\tline6pcm-\u003eout.count -= n * frame_factor;\n 180:\t\t\t\tfsize = n;\n 181:\t\t\t}\n 182:\t\n 183:\t\t\tfsize = bytes_per_frame;\n 184:\t\t\tfsize = min(fsize, line6pcm-\u003emax_packet_size_out);\n 185:\t\n 186:\t\t\tfout-\u003eoffset = urb_size;\n 187:\t\t\tfout-\u003elength = fsize;\n 188:\t\t\turb_size += fsize;\n 189:\t\t}\n 190:\t\n 191:\t\tif (urb_size == 0) {\n 192:\t\t\t/ can't determine URB size /\n 193:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"driver bug: urb_size = 0\\n\");\n 194:\t\t\treturn -EINVAL;\n 195:\t\t}\n 196:\t\n 197:\t\turb_frames = urb_size / bytes_per_frame;\n 198:\t\turb_out-\u003etransfer_buffer =\n 199:\t\t line6pcm-\u003eout.buffer +\n 200:\t\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\n 201:\t\turb_out-\u003etransfer_buffer_length = urb_size;\n 202:\t\turb_out-\u003econtext = line6pcm;\n 203:\t\n 204:\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running) \u0026\u0026\n 205:\t\t !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags)) {\n 206:\t\t\tstruct snd_pcm_runtime runtime =\n 207:\t\t\t get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK)-\u003eruntime;\n 208:\t\n 209:\t\t\tif (line6pcm-\u003eout.pos + urb_frames \u003e runtime-\u003ebuffer_size) {\n 210:\t\t\t\t/\n 211:\t\t\t\t The transferred area goes over buffer boundary,\n 212:\t\t\t\t copy the data to the temp buffer.\n 213:\t\t\t\t */\n 214:\t\t\t\tint len;\n 215:\t\n 216:\t\t\t\tlen = runtime-\u003ebuffer_size - line6pcm-\u003eout.pos;\n 217:\t\n 218:\t\t\t\tif (len \u003e 0) {\n 219:\t\t\t\t\tmemcpy(urb_out-\u003etransfer_buffer,\n" }
13/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30075 output: 30 thoughts: 574 Thoughts: My Analysis of a Potential Buffer Overflow in the Line6 Audio Driver Okay, so I'm looking at this code and immediately see a potential problem in how `urb_out->transfer_buffer` is being handled. Specifically, the lines where they calculate the buffer pointer and size, namely: `urb_out->transfer_buffer = line6pcm->out.buffer + index * LINE6_ISO_PACKETS * line6pcm->max_packet_size_out;` and `urb_size += fsize;` The core issue seems to be that if the size of the data (`fsize`) exceeds the maximum packet size (`line6pcm->max_packet_size_out`), we're going to have an overflow, either when writing to the buffer or during USB transmission. This could happen if a previous frame size calculation (`line6pcm->prev_fsize * bytes_per_frame`) was incorrectly large. It also looks like a larger than expected value for `n * bytes_per_frame` can also cause this overflow. Now, looking at the capture side, it looks like there is a check to see if a packet received is too large. However, if a corrupted or large packet is sent in the capture path, the value of `line6pcm->prev_fsize` might get updated to a bad value. The problem then propagates to the output path via: `fsize = line6pcm->prev_fsize; fsize *= bytes_per_frame;` which makes the out path vulnerable to an overflow condition. The proposed solution - `fsize = min(fsize, line6pcm->max_packet_size_out);` - looks like a clean and effective way to clamp the size and prevent the overflow. It's a classic and good defense mechanism. Now, the question is, how easily can we trigger this in a realistic scenario, and does syzkaller help us? I need to understand if the code path is reachable through fuzzing. Can we force `fsize` to be larger than `line6pcm->max_packet_size_out` with a maliciously crafted input? My initial thought is syzkaller, which is perfect for this. I know it supports USB emulation using `raw_gadget`, `vhci`, and `syz_usb_connect`. The key questions are: Does syzkaller already have descriptors for Line6 devices, or can it connect arbitrary USB devices? If we can connect any device, all we need is the correct VID/PID or the class of the Line6 devices. I need to go check the kernel sources and find the VID/PID of the Line6 device to confirm and assess the feasibility of triggering this bug using syzkaller. If that checks out, we can craft a test case to exploit the buffer overflow condition.
14/2	2026/09/21 01:50	tool	grepper	0m Args: { "Expression": "USB_DEVICE", "PathPrefix": "sound/usb/line6/" } Results: { "Output": "sound/usb/line6/pod.c=366=static int pod_init(struct usb_line6 line6,\n--\nsound/usb/line6/pod.c-407-\nsound/usb/line6/pod.c:408:#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)\nsound/usb/line6/pod.c:409:#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)\nsound/usb/line6/pod.c-410-\n--\nsound/usb/line6/podhd.c=367=static int podhd_init(struct usb_line6 line6,\n--\nsound/usb/line6/podhd.c-431-\nsound/usb/line6/podhd.c:432:#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)\nsound/usb/line6/podhd.c:433:#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)\nsound/usb/line6/podhd.c-434-\n--\nsound/usb/line6/toneport.c=462=static int toneport_reset_resume(struct usb_interface interface)\n--\nsound/usb/line6/toneport.c-472-\nsound/usb/line6/toneport.c:473:#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)\nsound/usb/line6/toneport.c:474:#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)\nsound/usb/line6/toneport.c-475-\n--\nsound/usb/line6/variax.c=158=static int variax_init(struct usb_line6 line6,\n--\nsound/usb/line6/variax.c-179-\nsound/usb/line6/variax.c:180:#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)\nsound/usb/line6/variax.c:181:#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)\nsound/usb/line6/variax.c-182-\n" }
15/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 31911 output: 34 thoughts: 47 Thoughts: Here's my thought process, as if I were analyzing this code: Analyzing the Call Stack: `submit_audio_out_urb` Okay, so I need to understand where `submit_audio_out_urb` is being called from. That function is pretty crucial, and I need to figure out the context of its execution. My immediate focus is on the `sound/usb/line6/playback.c` file. This tells me the relevant audio playback code for a Line 6 USB device is my point of focus. I'm assuming that it is responsible for moving audio data to the output. Let me check the callers of `submit_audio_out_urb` within that file, and then I'll be able to work out why the callstack is a relevant concern.
16/2	2026/09/21 01:50	tool	grepper	0m Args: { "Expression": "submit_audio_out_urb", "PathPrefix": "sound/usb/line6/" } Results: { "Output": "sound/usb/line6/playback.c=108=static void add_monitor_signal(struct urb urb_out, unsigned char signal,\n--\nsound/usb/line6/playback.c-139-/\nsound/usb/line6/playback.c:140:static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\nsound/usb/line6/playback.c-141-{\n--\nsound/usb/line6/playback.c=287=int line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-291-\tfor (i = 0; i \u003c line6pcm-\u003eline6-\u003eiso_buffers; ++i) {\nsound/usb/line6/playback.c:292:\t\tret = submit_audio_out_urb(line6pcm);\nsound/usb/line6/playback.c-293-\t\tif (ret \u003c 0)\n--\nsound/usb/line6/playback.c=303=static void audio_out_callback(struct urb urb)\n--\nsound/usb/line6/playback.c-354-\tif (!shutdown) {\nsound/usb/line6/playback.c:355:\t\tsubmit_audio_out_urb(line6pcm);\nsound/usb/line6/playback.c-356-\n" }
17/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 32523 output: 39 thoughts: 20 Thoughts: Here's a breakdown of my thought process, as if I were analyzing calls to `line6_submit_audio_out_all_urbs`: Diving into the `line6_submit_audio_out_all_urbs` Calls Alright, let's start dissecting the callers of `line6_submit_audio_out_all_urbs`. My first instinct is to understand the context. What's driving this function? I need to figure out the architectural layer it sits within. Is it low-level audio hardware interaction? Network communication? Or something further up, closer to an application level? That determines my approach. I'll be looking for patterns. Are there specific modules or threads that consistently invoke it? Are the call sites clustered around a particular feature or functionality? Understanding the calling context is key. Then, I'll need to consider what information is passed to `line6_submit_audio_out_all_urbs`. That's going to tell me what data this function is actually acting on. Are we talking about audio buffers? Configuration parameters? URB data as the name suggests? The data types and their structures will provide crucial insights into its purpose and potential bottlenecks. Next, I need to look at any preconditions. Are there specific states or initializations that must be in place before calling this function? Are there any obvious locks or synchronization primitives involved? Ignoring this detail will bite me later. Finally, I'll be thinking about the expected outcome. What does the system do after this function call? Does it immediately trigger audio output? Does it queue something for later processing? The subsequent actions will define the role of this function in the audio system. Where is the data going after this call? Is this the last stop, or are we just preparing a data structure? Is there an obvious latency aspect to consider? I'm ready to dig in and unravel this function!
18/2	2026/09/21 01:50	tool	grepper	0m Args: { "Expression": "line6_submit_audio_out_all_urbs", "PathPrefix": "sound/usb/line6/" } Results: { "Output": "sound/usb/line6/pcm.c=182=static int line6_stream_start(struct snd_line6_pcm line6pcm, int direction,\n--\nsound/usb/line6/pcm.c-193-\t\tif (direction == SNDRV_PCM_STREAM_PLAYBACK)\nsound/usb/line6/pcm.c:194:\t\t\tret = line6_submit_audio_out_all_urbs(line6pcm);\nsound/usb/line6/pcm.c-195-\t\telse\n--\nsound/usb/line6/playback.c=140=static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-286- /\nsound/usb/line6/playback.c:287:int line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/playback.c-288-{\n--\nsound/usb/line6/playback.h=28=extern int line6_create_audio_out_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/playback.h:29:extern int line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/playback.h-30-\n" }
19/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33343 output: 34 thoughts: 696 Thoughts: Analyzing the Reachability and Fuzzing Potential of the Line6 Audio Driver Okay, so the ALSA PCM trigger starts the stream by calling `line6_stream_start`. Let's trace this: it goes through `snd_line6_trigger`, then `line6_stream_start` which is responsible for setting up the stream and type. The meat of the output is in `line6_submit_audio_out_all_urbs` then ultimately `submit_audio_out_urb`. The cycle continues with the completion of the URB. The `audio_out_callback` is called, and a new `submit_audio_out_urb` is triggered. Similarly, the same happens on the input side with `audio_in_callback` and use of `line6pcm->prev_fsize` during playback. Now, the crucial question: can this code be executed within a standard virtualized environment, like QEMU, which is critical for fuzzing? I know from experience that virtual USB devices can be connected. Specifically, we can use USB Raw Gadget or the USB dummy HCD / vhci_hcd, both supported by syzkaller. This is excellent news because, once the device is probed, ALSA PCM playback operations using the standard `/dev/snd/pcm` ioctls directly exercise the code path I just traced: `snd_line6_trigger` -> `line6_submit_audio_out_all_urbs` -> `submit_audio_out_urb`. So, we're good there. Wait a second, let's circle back to the core principle. The instructions are clear: reachability is the primary gate! If the code's structurally unreachable in a standard environment, it's a no-go for fuzzing, regardless of how complex it is. But in this case, the code is reachable. Virtual buses such as virtio and USB Gadget are mentioned as being accessible. Is the modified code reachable? Yes! It's right in `sound/usb/line6/playback.c`, inside that `submit_audio_out_urb()` function. So this confirms it. Is this patch worth fuzzing? Absolutely. It modifies the logic around this `fsize = min(fsize, line6pcm->max_packet_size_out);` clamp. This is a critical area, potentially preventing buffer overflows. Okay, let's step back and consider what the consequences are if `fsize` wasn't* clamped. We have: `fout->length = fsize;`, `urb_size += fsize;`, and `urb_out->transfer_buffer_length = urb_size;`. If the clamp isn't there, we're talking about calculations that are directly and immediately affecting the size of outgoing audio URBs. This clamp is directly related to the calculation to keep it within the `line6pcm->max_packet_size_out`. Finally, to be completely sure, I should double-check the configuration options. I'll need to examine `sound/usb/line6/Makefile` and `sound/usb/line6/Kconfig` carefully to see what configurations enable this specific functionality. This will provide a solid assurance that the code is built when the relevant features are enabled.
20/2	2026/09/21 01:50	tool	read-file	0m Args: { "File": "sound/usb/line6/Makefile", "FirstLine": 1, "LineCount": 30 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0\n 2:\tsnd-usb-line6-y := \t\t\\\n 3:\t\t\tcapture.o\t\\\n 4:\t\t\tdriver.o\t\\\n 5:\t\t\tmidi.o\t\t\\\n 6:\t\t\tmidibuf.o\t\\\n 7:\t\t\tpcm.o\t\t\\\n 8:\t\t\tplayback.o\n 9:\t\n 10:\tsnd-usb-pod-y := pod.o\n 11:\tsnd-usb-podhd-y := podhd.o\n 12:\tsnd-usb-toneport-y := toneport.o\n 13:\tsnd-usb-variax-y := variax.o\n 14:\t\n 15:\tobj-$(CONFIG_SND_USB_LINE6)\t+= snd-usb-line6.o\n 16:\tobj-$(CONFIG_SND_USB_POD)\t+= snd-usb-pod.o\n 17:\tobj-$(CONFIG_SND_USB_PODHD)\t+= snd-usb-podhd.o\n 18:\tobj-$(CONFIG_SND_USB_TONEPORT)\t+= snd-usb-toneport.o\n 19:\tobj-$(CONFIG_SND_USB_VARIAX)\t+= snd-usb-variax.o\n" }
21/2	2026/09/21 01:50	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35131 output: 33 thoughts: 148 Thoughts: Investigating the Configuration of Line 6 USB Audio Devices Okay, so I've stumbled upon `CONFIG_SND_USB_LINE6`, and immediately something jumps out – it's a tristate option but lacks a prompt. That's a bit unusual, and warrants further investigation. I can see the configuration snippet now: ``` config SND_USB_LINE6 tristate select SND_RAWMIDI select SND_PCM select SND_HWDEP ``` It's dependent on `SND_RAWMIDI`, `SND_PCM` and `SND_HWDEP`, as one would expect. But what really piques my interest is the selection. It's being pulled in by `SND_USB_POD`, `SND_USB_PODHD`, `SND_USB_TONEPORT`, and `SND_USB_VARIAX`. My next thought is, do these Line 6 devices actually support PCM playback? If they do, then it would be a critical path for audio processing. I need to confirm this. To do that, I'm going to quickly search the `sound/usb/line6/` directory for any references to `LINE6_CAP_PCM`. This should give me a clear indication of whether these devices are capable of PCM audio, and how they implement it in the driver.
22/2	2026/09/21 01:51	tool	grepper	0m Args: { "Expression": "LINE6_CAP_PCM", "PathPrefix": "sound/usb/line6/" } Results: { "Output": "sound/usb/line6/driver.h=98=enum {\n--\nsound/usb/line6/driver.h-101-\t/* device supports PCM input/output via USB /\nsound/usb/line6/driver.h:102:\tLINE6_CAP_PCM =\t\t1 \u003c\u003c 1,\nsound/usb/line6/driver.h-103-\t/ device supports hardware monitoring /\n--\nsound/usb/line6/pcm.c=515=int line6_init_pcm(struct usb_line6 line6,\n--\nsound/usb/line6/pcm.c-523-\nsound/usb/line6/pcm.c:524:\tif (!(line6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_PCM))\nsound/usb/line6/pcm.c-525-\t\treturn 0;\t/* skip PCM initialization and report success /\n--\nsound/usb/line6/pod.c=425=static const struct line6_properties pod_properties_table[] = {\n--\nsound/usb/line6/pod.c-430-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:431:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-432-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/pod.c-443-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:444:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-445-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/pod.c-456-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:457:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-458-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/pod.c-479-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:480:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-481-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/pod.c-492-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:493:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-494-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/pod.c-505-\t\t\t\t\| LINE6_CAP_CONTROL_MIDI\nsound/usb/line6/pod.c:506:\t\t\t\t\| LINE6_CAP_PCM\nsound/usb/line6/pod.c-507-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/podhd.c=367=static int podhd_init(struct usb_line6 line6,\n--\nsound/usb/line6/podhd.c-401-\nsound/usb/line6/podhd.c:402:\tif (pod-\u003eline6.properties-\u003ecapabilities \u0026 LINE6_CAP_PCM) {\nsound/usb/line6/podhd.c-403-\t\t/* initialize PCM subsystem: /\n--\nsound/usb/line6/podhd.c=452=static const struct line6_properties podhd_properties_table[] = {\n--\nsound/usb/line6/podhd.c-455-\t\t.name = \"POD HD300\",\nsound/usb/line6/podhd.c:456:\t\t.capabilities\t= LINE6_CAP_PCM\nsound/usb/line6/podhd.c-457-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/podhd.c-466-\t\t.name = \"POD HD400\",\nsound/usb/line6/podhd.c:467:\t\t.capabilities\t= LINE6_CAP_PCM\nsound/usb/line6/podhd.c-468-\t\t\t\t\| LINE6_CAP_HWMON,\n--\nsound/usb/line6/podhd.c-477-\t\t.name = \"POD HD500\",\nsound/usb/line6/podhd.c:478:\t\t.capabilities\t= LINE6_CAP_PCM \| LINE6_CAP_CONTROL\nsound/usb/line6/podhd.c-479-\t\t\t\t\| LINE6_CAP_HWMON \| LINE6_CAP_HWMON_CTL,\n--\nsound/usb/line6/podhd.c-490-\t\t.capabilities\t= LINE6_CAP_CONTROL \| LINE6_CAP_CONTROL_INFO\nsound/usb/line6/podhd.c:491:\t\t\t\t\| LINE6_CAP_PCM \| LINE6_CAP_HWMON \| LINE6_CAP_IN_NEEDS_OUT,\nsound/usb/line6/podhd.c-492-\t\t.altsetting = 1,\n--\nsound/usb/line6/podhd.c-502-\t\t.capabilities\t= LINE6_CAP_CONTROL \| LINE6_CAP_CONTROL_INFO\nsound/usb/line6/podhd.c:503:\t\t\t\t\| LINE6_CAP_PCM \| LINE6_CAP_HWMON \| LINE6_CAP_IN_NEEDS_OUT,\nsound/usb/line6/podhd.c-504-\t\t.altsetting = 1,\n--\nsound/usb/line6/podhd.c-514-\t\t.capabilities\t= LINE6_CAP_CONTROL \| LINE6_CAP_HWMON_CTL\nsound/usb/line6/podhd.c:515:\t\t\t\t\| LINE6_CAP_PCM \| LINE6_CAP_HWMON,\nsound/usb/line6/podhd.c-516-\t\t.altsetting = 1,\n--\nsound/usb/line6/podhd.c-526-\t\t.capabilities = LINE6_CAP_CONTROL\nsound/usb/line6/podhd.c:527:\t\t\t\| LINE6_CAP_PCM \| LINE6_CAP_HWMON,\nsound/usb/line6/podhd.c-528-\t\t.altsetting = 1,\n--\nsound/usb/line6/podhd.c-538-\t\t.capabilities\t= LINE6_CAP_CONTROL \| LINE6_CAP_CONTROL_INFO\nsound/usb/line6/podhd.c:539:\t\t\t\t\| LINE6_CAP_PCM \| LINE6_CAP_HWMON \| LINE6_CAP_IN_NEEDS_OUT,\nsound/usb/line6/podhd.c-540-\t\t.altsetting = 1,\n--\nsound/usb/line6/podhd.c-549-\t\t.name = \"POD HD PRO\",\nsound/usb/line6/podhd.c:550:\t\t.capabilities\t= LINE6_CAP_PCM \| LINE6_CAP_CONTROL\nsound/usb/line6/podhd.c-551-\t\t\t\t\| LINE6_CAP_HWMON \| LINE6_CAP_HWMON_CTL \| LINE6_CAP_IN_NEEDS_OUT,\n--\nsound/usb/line6/toneport.c=490=static const struct line6_properties toneport_properties_table[] = {\n--\nsound/usb/line6/toneport.c-493-\t\t.name = \"GuitarPort\",\nsound/usb/line6/toneport.c:494:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-495-\t\t.altsetting = 2, / 1..4 seem to be ok /\n--\nsound/usb/line6/toneport.c-502-\t\t.name = \"POD Studio GX\",\nsound/usb/line6/toneport.c:503:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-504-\t\t.altsetting = 2, / 1..4 seem to be ok /\n--\nsound/usb/line6/toneport.c-511-\t\t.name = \"POD Studio UX1\",\nsound/usb/line6/toneport.c:512:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-513-\t\t.altsetting = 2, / 1..4 seem to be ok /\n--\nsound/usb/line6/toneport.c-520-\t\t.name = \"POD Studio UX2\",\nsound/usb/line6/toneport.c:521:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-522-\t\t.altsetting = 2, / defaults to 44.1kHz, 16-bit /\n--\nsound/usb/line6/toneport.c-529-\t\t.name = \"TonePort GX\",\nsound/usb/line6/toneport.c:530:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-531-\t\t.altsetting = 2, / 1..4 seem to be ok /\n--\nsound/usb/line6/toneport.c-538-\t\t.name = \"TonePort UX1\",\nsound/usb/line6/toneport.c:539:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-540-\t\t.altsetting = 2, / 1..4 seem to be ok /\n--\nsound/usb/line6/toneport.c-547-\t\t.name = \"TonePort UX2\",\nsound/usb/line6/toneport.c:548:\t\t.capabilities\t= LINE6_CAP_PCM,\nsound/usb/line6/toneport.c-549-\t\t.altsetting = 2, / defaults to 44.1kHz, 16-bit */\n" }
23/2	2026/09/21 01:51	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 38110 output: 32 thoughts: 92 Thoughts: Okay, here's my summary, presented as a stream of thought: Checking the Line 6 USB Audio Module Dependencies Right, so I'm looking at these Line 6 USB audio drivers: `CONFIG_SND_USB_POD`, `CONFIG_SND_USB_PODHD`, and `CONFIG_SND_USB_TONEPORT`. They all seem to rely on the `snd-usb-line6.ko` module, and from what I recall, they present PCM audio capabilities, which is what I'd expect. Now, I need to confirm this understanding and, more importantly, figure out the underlying dependencies. I need to dive into the Kconfig files, specifically `sound/usb/Kconfig` and `sound/Kconfig`, to see precisely what other options or modules are required for `SND_USB_POD`, `SND_USB_TONEPORT`, and the others to function correctly. This will give me a clear picture of the build configuration and any potential conflicts or shared dependencies. Time to dig in.
24/2	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/Kconfig", "FirstLine": 1, "LineCount": 40 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\t# ALSA USB drivers\n 3:\t\n 4:\tmenuconfig SND_USB\n 5:\t\tbool \"USB sound devices\"\n 6:\t\tdepends on USB\n 7:\t\tdefault y\n 8:\t\thelp\n 9:\t\t Support for sound devices connected via the USB bus.\n 10:\t\n 11:\tif SND_USB \u0026\u0026 USB\n 12:\t\n 13:\tconfig SND_USB_AUDIO\n 14:\t\ttristate \"USB Audio/MIDI driver\"\n 15:\t\tselect SND_HWDEP\n 16:\t\tselect SND_RAWMIDI\n 17:\t\tselect SND_PCM\n 18:\t\tselect SND_UMP if SND_USB_AUDIO_MIDI_V2\n 19:\t\tselect BITREVERSE\n 20:\t\tselect SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER \u0026\u0026 (MEDIA_SUPPORT=y \|\| MEDIA_SUPPORT=SND_USB_AUDIO)\n 21:\t\thelp\n 22:\t\t Say Y here to include support for USB audio and USB MIDI\n 23:\t\t devices.\n 24:\t\n 25:\t\t To compile this driver as a module, choose M here: the module\n 26:\t\t will be called snd-usb-audio.\n 27:\t\n 28:\tconfig SND_USB_AUDIO_MIDI_V2\n 29:\t\tbool \"MIDI 2.0 support by USB Audio driver\"\n 30:\t\tdepends on SND_USB_AUDIO\n 31:\t\thelp\n 32:\t\t Say Y here to include the support for MIDI 2.0 by USB Audio driver.\n 33:\t\t When the config is set, the driver tries to probe MIDI 2.0 interface\n 34:\t\t at first, then falls back to MIDI 1.0 interface as default.\n 35:\t\t The MIDI 2.0 support can be disabled dynamically via midi2_enable\n 36:\t\t module option, too.\n 37:\t\n 38:\tconfig SND_USB_AUDIO_USE_MEDIA_CONTROLLER\n 39:\t\tbool\n 40:\t\n" }
25/2	2026/09/21 01:51	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39006 output: 37 thoughts: 1268 Thoughts: Line 6 USB Audio Module Analysis Okay, let's break this down. First, I need to understand how the Line 6 USB audio support is configured within the kernel. The `if SND_USB && USB` guard in `sound/usb/Kconfig` is key; it determines whether the entire `sound/usb/line6/Kconfig` branch is even considered. Now I'll check how `SND_USB_LINE6` itself works, and its dependencies. It seems that `SND_USB_LINE6` doesn't have a visible prompt, so it's directly enabled. Looking at `sound/usb/line6/Kconfig`, enabling `SND_USB_POD`, `SND_USB_PODHD`, `SND_USB_TONEPORT`, or even directly selecting `SND_USB_LINE6` will all compile `snd-usb-line6.o`, and specifically that includes `playback.o`. Given that `SND_USB_LINE6` isn't directly user-visible, and is implicitly selected, it will be selected through another config, like the ones mentioned. So, now, what's best to include in `EnableConfigs`? The best approach seems to be to include `SND_USB_LINE6` and either `SND_USB_POD`, or `SND_USB_TONEPORT` since these are direct configurations. `Syzkaller` will then enable these, which is important for configurations without visible prompts. I'm going with `SND_USB_LINE6` and a few of the device-specific ones. This ensures the module is compiled. Now, let's shift to the `FocusSymbols`. The function modified is `submit_audio_out_urb`, which is defined as `static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm)`. The "static" keyword is a potential issue, as these often get inlined by the compiler. It's called in two locations in `playback.c`: `line6_submit_audio_out_all_urbs` and `audio_out_callback`. I need to check if `line6_submit_audio_out_all_urbs` is exported or in a header. Yup, `line6_submit_audio_out_all_urbs` is declared as an external symbol in `sound/usb/line6/playback.h`. Since `submit_audio_out_urb` is about 60 lines long, and is called from multiple locations, it might not be inlined. If not, it'll show up in the object file as a symbol, which is what I need. Syzkaller documentation indicates that compiler-inlined static functions (like static inlines) lack distinct symbol addresses in `vmlinux`. However, `submit_audio_out_urb` is a `static` function in a `.c` file and not a static inline in `.h`, so it may or may not be inlined. Therefore, to cover all bases, I should include `line6_submit_audio_out_all_urbs` and `audio_out_callback` as focus symbols. Also, it's a good idea to thoroughly read `playback.c` itself to get a complete picture.
26/2	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 1, "LineCount": 100 } Results: { "Contents": " 1:\t// SPDX-License-Identifier: GPL-2.0-only\n 2:\t/\n 3:\t Line 6 Linux USB driver\n 4:\t \n 5:\t Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)\n 6:\t /\n 7:\t\n 8:\t#include \u003clinux/slab.h\u003e\n 9:\t#include \u003csound/core.h\u003e\n 10:\t#include \u003csound/pcm.h\u003e\n 11:\t#include \u003csound/pcm_params.h\u003e\n 12:\t\n 13:\t#include \"capture.h\"\n 14:\t#include \"driver.h\"\n 15:\t#include \"pcm.h\"\n 16:\t#include \"playback.h\"\n 17:\t\n 18:\t/\n 19:\t\tSoftware stereo volume control.\n 20:\t/\n 21:\tstatic void change_volume(struct urb urb_out, int volume[],\n 22:\t\t\t\t int bytes_per_frame)\n 23:\t{\n 24:\t\tint chn = 0;\n 25:\t\n 26:\t\tif (volume[0] == 256 \u0026\u0026 volume[1] == 256)\n 27:\t\t\treturn;\t\t/* maximum volume - no change /\n 28:\t\n 29:\t\tif (bytes_per_frame == 4) {\n 30:\t\t\t__le16 p, buf_end;\n 31:\t\n 32:\t\t\tp = (__le16 )urb_out-\u003etransfer_buffer;\n 33:\t\t\tbuf_end = p + urb_out-\u003etransfer_buffer_length / sizeof(p);\n 34:\t\n 35:\t\t\tfor (; p \u003c buf_end; ++p) {\n 36:\t\t\t\tshort pv = le16_to_cpu(p);\n 37:\t\t\t\tint val = (pv * volume[chn \u0026 1]) \u003e\u003e 8;\n 38:\t\t\t\tpv = clamp(val, -0x8000, 0x7fff);\n 39:\t\t\t\tp = cpu_to_le16(pv);\n 40:\t\t\t\t++chn;\n 41:\t\t\t}\n 42:\t\t} else if (bytes_per_frame == 6) {\n 43:\t\t\tunsigned char p, buf_end;\n 44:\t\n 45:\t\t\tp = (unsigned char )urb_out-\u003etransfer_buffer;\n 46:\t\t\tbuf_end = p + urb_out-\u003etransfer_buffer_length;\n 47:\t\n 48:\t\t\tfor (; p \u003c buf_end; p += 3) {\n 49:\t\t\t\tint val;\n 50:\t\n 51:\t\t\t\tval = p[0] + (p[1] \u003c\u003c 8) + ((signed char)p[2] \u003c\u003c 16);\n 52:\t\t\t\tval = (val * volume[chn \u0026 1]) \u003e\u003e 8;\n 53:\t\t\t\tval = clamp(val, -0x800000, 0x7fffff);\n 54:\t\t\t\tp[0] = val;\n 55:\t\t\t\tp[1] = val \u003e\u003e 8;\n 56:\t\t\t\tp[2] = val \u003e\u003e 16;\n 57:\t\t\t\t++chn;\n 58:\t\t\t}\n 59:\t\t}\n 60:\t}\n 61:\t\n 62:\t/\n 63:\t\tCreate signal for impulse response test.\n 64:\t/\n 65:\tstatic void create_impulse_test_signal(struct snd_line6_pcm line6pcm,\n 66:\t\t\t\t\t struct urb urb_out, int bytes_per_frame)\n 67:\t{\n 68:\t\tint frames = urb_out-\u003etransfer_buffer_length / bytes_per_frame;\n 69:\t\n 70:\t\tif (bytes_per_frame == 4) {\n 71:\t\t\tint i;\n 72:\t\t\tshort pi = (short )line6pcm-\u003eprev_fbuf;\n 73:\t\t\tshort po = (short )urb_out-\u003etransfer_buffer;\n 74:\t\n 75:\t\t\tfor (i = 0; i \u003c frames; ++i) {\n 76:\t\t\t\tpo[0] = pi[0];\n 77:\t\t\t\tpo[1] = 0;\n 78:\t\t\t\tpi += 2;\n 79:\t\t\t\tpo += 2;\n 80:\t\t\t}\n 81:\t\t} else if (bytes_per_frame == 6) {\n 82:\t\t\tint i, j;\n 83:\t\t\tunsigned char pi = line6pcm-\u003eprev_fbuf;\n 84:\t\t\tunsigned char po = urb_out-\u003etransfer_buffer;\n 85:\t\n 86:\t\t\tfor (i = 0; i \u003c frames; ++i) {\n 87:\t\t\t\tfor (j = 0; j \u003c bytes_per_frame / 2; ++j)\n 88:\t\t\t\t\tpo[j] = pi[j];\n 89:\t\n 90:\t\t\t\tfor (; j \u003c bytes_per_frame; ++j)\n 91:\t\t\t\t\tpo[j] = 0;\n 92:\t\n 93:\t\t\t\tpi += bytes_per_frame;\n 94:\t\t\t\tpo += bytes_per_frame;\n 95:\t\t\t}\n 96:\t\t}\n 97:\t\tif (--line6pcm-\u003eimpulse_count \u003c= 0) {\n 98:\t\t\t((unsigned char *)(urb_out-\u003etransfer_buffer))[bytes_per_frame -\n 99:\t\t\t\t\t\t\t\t 1] =\n 100:\t\t\t line6pcm-\u003eimpulse_volume;\n" }
27/2	2026/09/21 01:51	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42464 output: 39 thoughts: 12 Thoughts: Okay, here's my interpretation of that thought process, assuming I'm deeply familiar with `playback.c` and its context. Diving Back into Playback.c Alright, time to get back to it. Let's see... the focus is clearly on the implementation of the playback functionality, and what's next? Probably some subtle interactions or less-obvious bugs. It's a complex beast, and I know where I left off, but I need a fresh look. I've been working on this code long enough to have a good sense of how things are laid out, but I have to carefully consider the whole process of playback. I know I have a bunch of ideas, thoughts, and areas where problems are likely. Let's get reading and see what's happening.
28/2	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 280, "LineCount": 100 } Results: { "Contents": " 280:\t\treturn 0;\n 281:\t}\n 282:\t\n 283:\t/\n 284:\t\tSubmit all currently available playback URBs.\n 285:\t\tmust be called in line6pcm-\u003eout.lock context\n 286:\t /\n 287:\tint line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm)\n 288:\t{\n 289:\t\tint ret = 0, i;\n 290:\t\n 291:\t\tfor (i = 0; i \u003c line6pcm-\u003eline6-\u003eiso_buffers; ++i) {\n 292:\t\t\tret = submit_audio_out_urb(line6pcm);\n 293:\t\t\tif (ret \u003c 0)\n 294:\t\t\t\tbreak;\n 295:\t\t}\n 296:\t\n 297:\t\treturn ret;\n 298:\t}\n 299:\t\n 300:\t/\n 301:\t\tCallback for completed playback URB.\n 302:\t/\n 303:\tstatic void audio_out_callback(struct urb urb)\n 304:\t{\n 305:\t\tint i, index, length = 0, shutdown = 0;\n 306:\t\tunsigned long flags;\n 307:\t\tstruct snd_line6_pcm line6pcm = (struct snd_line6_pcm )urb-\u003econtext;\n 308:\t\tstruct snd_pcm_substream substream =\n 309:\t\t get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK);\n 310:\t\tconst int bytes_per_frame =\n 311:\t\t\tline6pcm-\u003eproperties-\u003ebytes_per_channel \n 312:\t\t\tline6pcm-\u003eproperties-\u003eplayback_hw.channels_max;\n 313:\t\n 314:\t#if USE_CLEAR_BUFFER_WORKAROUND\n 315:\t\tmemset(urb-\u003etransfer_buffer, 0, urb-\u003etransfer_buffer_length);\n 316:\t#endif\n 317:\t\n 318:\t\tline6pcm-\u003eout.last_frame = urb-\u003estart_frame;\n 319:\t\n 320:\t\t/* find index of URB /\n 321:\t\tfor (index = 0; index \u003c line6pcm-\u003eline6-\u003eiso_buffers; index++)\n 322:\t\t\tif (urb == line6pcm-\u003eout.urbs[index])\n 323:\t\t\t\tbreak;\n 324:\t\n 325:\t\tif (index \u003e= line6pcm-\u003eline6-\u003eiso_buffers)\n 326:\t\t\treturn;\t\t/ URB has been unlinked asynchronously /\n 327:\t\n 328:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; i++)\n 329:\t\t\tlength += urb-\u003eiso_frame_desc[i].length;\n 330:\t\n 331:\t\tspin_lock_irqsave(\u0026line6pcm-\u003eout.lock, flags);\n 332:\t\n 333:\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running)) {\n 334:\t\t\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\n 335:\t\n 336:\t\t\tline6pcm-\u003eout.pos_done +=\n 337:\t\t\t length / bytes_per_frame;\n 338:\t\n 339:\t\t\tif (line6pcm-\u003eout.pos_done \u003e= runtime-\u003ebuffer_size)\n 340:\t\t\t\tline6pcm-\u003eout.pos_done -= runtime-\u003ebuffer_size;\n 341:\t\t}\n 342:\t\n 343:\t\tclear_bit(index, \u0026line6pcm-\u003eout.active_urbs);\n 344:\t\n 345:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; i++)\n 346:\t\t\tif (urb-\u003eiso_frame_desc[i].status == -EXDEV) {\n 347:\t\t\t\tshutdown = 1;\n 348:\t\t\t\tbreak;\n 349:\t\t\t}\n 350:\t\n 351:\t\tif (test_and_clear_bit(index, \u0026line6pcm-\u003eout.unlink_urbs))\n 352:\t\t\tshutdown = 1;\n 353:\t\n 354:\t\tif (!shutdown) {\n 355:\t\t\tsubmit_audio_out_urb(line6pcm);\n 356:\t\n 357:\t\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running)) {\n 358:\t\t\t\tline6pcm-\u003eout.bytes += length;\n 359:\t\t\t\tif (line6pcm-\u003eout.bytes \u003e= line6pcm-\u003eout.period) {\n 360:\t\t\t\t\tline6pcm-\u003eout.bytes %= line6pcm-\u003eout.period;\n 361:\t\t\t\t\tspin_unlock(\u0026line6pcm-\u003eout.lock);\n 362:\t\t\t\t\tsnd_pcm_period_elapsed(substream);\n 363:\t\t\t\t\tspin_lock(\u0026line6pcm-\u003eout.lock);\n 364:\t\t\t\t}\n 365:\t\t\t}\n 366:\t\t}\n 367:\t\tspin_unlock_irqrestore(\u0026line6pcm-\u003eout.lock, flags);\n 368:\t}\n 369:\t\n 370:\t/* open playback callback /\n 371:\tstatic int snd_line6_playback_open(struct snd_pcm_substream substream)\n 372:\t{\n 373:\t\tint err;\n 374:\t\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\n 375:\t\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\n 376:\t\n 377:\t\terr = snd_pcm_hw_constraint_ratdens(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,\n 378:\t\t\t\t\t\t \u0026line6pcm-\u003eproperties-\u003erates);\n 379:\t\tif (err \u003c 0)\n" }
29/2	2026/09/21 01:51	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 44254 output: 190 thoughts: 1200 Thoughts: Analysis of the Line6 USB Audio Driver for Fuzzing Okay, let's break this down. My goal is to assess the fuzzing potential of this specific code modification. I'm focusing on the `submit_audio_out_urb` function within the Line6 USB audio driver. It seems this function is the core of the audio output process. I see that `submit_audio_out_urb` is called from two main places: `line6_submit_audio_out_all_urbs`, used during stream startup via `snd_line6_trigger`, and `audio_out_callback`, which handles URB completion. The `snd_line6_playback_ops` struct provides the necessary ALSA PCM callbacks for the playback. The patch itself alters how the URB packet length (`fsize`) is calculated. The critical part is this: the packet size `fsize` is now capped by `line6pcm->max_packet_size_out` after being multiplied by `bytes_per_frame`. This looks like a classic clamp, which could potentially expose edge cases. The question then is, can this code be executed reliably? Absolutely. I know that standard virtualization environments (QEMU, syzkaller) can emulate USB devices using Raw Gadget or VHCI. This means I can connect and probe a Line6 USB audio device in those environments. I can trigger ALSA PCM playback using standard ioctls, so getting the code path exercised is definitely feasible. Is it worth fuzzing? Yes, without a doubt. Fuzzing the USB audio playback path, especially with unusual sample rates, frame sizes, and buffer configurations, is a good idea. This is because the clamping logic might introduce invariants, buffer underflows/overflows, or other issues related to edge cases. So, let's define the required parameters for `set-results`: 1. `WorthFuzzing`: True. 2. `Reasoning`: The patch modifies URB packet length calculation, introducing clamping logic that is reachable via standard USB device emulation and ALSA PCM playback, making it susceptible to edge case issues through fuzzing unusual configurations. 3. `FocusSymbols`: I need to include symbols to pinpoint the change: * `submit_audio_out_urb`: This is the function where the clamping logic resides. * `line6_submit_audio_out_all_urbs`: The function that starts streams. * `audio_out_callback`: The completion callback, critical for re-submitting URBs. * `snd_line6_trigger`: The ALSA PCM trigger function that starts the playback stream. 4. `EnableConfigs`: I need to ensure the correct kernel modules are compiled and linked. I have confirmed that the following configs are needed: * `SND_USB_LINE6` * `SND_USB_POD` * `SND_USB_TONEPORT` * `SND_USB_PODHD` No negative criteria apply here; the code is directly relevant, accessible, and executable. All is clear, and verified. Let's call `set-results`.
30/2	2026/09/21 01:51	tool	set-results	0m Args: { "EnableConfigs": [ "SND_USB_LINE6", "SND_USB_POD", "SND_USB_PODHD", "SND_USB_TONEPORT" ], "FocusSymbols": [ "submit_audio_out_urb", "line6_submit_audio_out_all_urbs", "audio_out_callback", "snd_line6_trigger" ], "Reasoning": "The patch modifies the calculation of playback URB packet size in the Line6 USB sound driver by clamping fsize to max_packet_size_out, preventing buffer overflows. Line6 USB audio devices can be emulated via USB gadget/raw-gadget in virtualized environments and exercised via standard ALSA PCM interfaces, making this reachable code worth fuzzing for boundary conditions and playback stability.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "SND_USB_LINE6", "SND_USB_POD", "SND_USB_PODHD", "SND_USB_TONEPORT" ], "FocusSymbols": [ "submit_audio_out_urb", "line6_submit_audio_out_all_urbs", "audio_out_callback", "snd_line6_trigger" ], "Reasoning": "The patch modifies the calculation of playback URB packet size in the Line6 USB sound driver by clamping fsize to max_packet_size_out, preventing buffer overflows. Line6 USB audio devices can be emulated via USB gadget/raw-gadget in virtualized environments and exercised via standard ALSA PCM interfaces, making this reachable code worth fuzzing for boundary conditions and playback stability.", "WorthFuzzing": true }
31/1	2026/09/21 01:51	action	If	0m Args: { "WorthFuzzing": true } Results: null
32/2	2026/09/21 01:51	agent	kmsan-evaluator	0m Model: core Args: null Results: { "KMSANReasoning": "The patch adds a bounds check (`fsize = min(fsize, line6pcm-\u003emax_packet_size_out)`) in `submit_audio_out_urb()` in `sound/usb/line6/playback.c`. \n\nPrior to this fix, if `fsize` exceeded `max_packet_size_out`, the cumulative `urb_size` could exceed the buffer allocated for each URB (`LINE6_ISO_PACKETS * max_packet_size_out`), resulting in slab out-of-bounds reads/writes during `memcpy()`, `memset()`, or USB transmission. Out-of-bounds accesses and buffer overflows are explicitly within the domain of KASAN, not KMSAN.\n\nThe patch does not introduce new allocations, does not read or branch on uninitialized variables, does not expose kernel memory to user space (info-leak), and does not cause surrounding code to read uninitialized buffer bytes. The buffer contents are explicitly populated either from the PCM runtime DMA buffer or zeroed with `memset()` for the full length of the transfer. Therefore, standard KASAN fuzzing is sufficient and a dedicated KMSAN session is not required.", "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 606a17c192944e903dd539eb7ac1d6c57c0b7e89 Author: syz-cluster <triage@syzkaller.com> Date: Mon Sep 21 01:50:07 2026 +0000 syz-cluster: applied patch under review diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c index 7ebaf125f9692..cfb20585c5ead 100644 --- a/sound/usb/line6/playback.c +++ b/sound/usb/line6/playback.c @@ -181,6 +181,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm line6pcm) } fsize = bytes_per_frame; + fsize = min(fsize, line6pcm->max_packet_size_out); fout->offset = urb_size; fout->length = fsize;
33/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 2066 output: 38 thoughts: 291 Thoughts: KMSAN Justification: Line6 Playback Patch Okay, so I've got this patch for `sound/usb/line6/playback.c` and the question is, does it warrant firing up a dedicated KMSAN session? Let's dissect this. Right, the diff... it's a `min()` operation being added to `submit_audio_out_urb`. Specifically, they're limiting `fsize` to `line6pcm->max_packet_size_out`. Hmm, making sure the frame size doesn't exceed the device's maximum packet size. Good defensive programming, potentially preventing some kind of buffer overflow or DMA overrun on the USB bus. Now, I need to get a better sense of the context around this change. I'm going to quickly check around the `submit_audio_out_urb` function in `sound/usb/line6/playback.c`, probably using something like `read-file` or `grepper` to see if there's any obvious vulnerability. Are there any other places in this function where we could run into issues? Are there existing checks in place that make this change more or less significant? I'll check the surrounding code for similar patterns of memory access and packet size calculations. The key here is to determine if this addition is critical in preventing a data race or memory corruption issue that KMSAN would catch, or if it's more of a good-practice, but low-risk, addition. If this `min()` operation prevents a read from potentially invalid memory which might be accessed in a tight loop I'd say that would be sufficient to justify the use of KMSAN.
34/3	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 140, "LineCount": 90 } Results: { "Contents": " 140:\tstatic int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n 141:\t{\n 142:\t\tint index;\n 143:\t\tint i, urb_size, urb_frames;\n 144:\t\tint ret;\n 145:\t\tconst int bytes_per_frame =\n 146:\t\t\tline6pcm-\u003eproperties-\u003ebytes_per_channel \n 147:\t\t\tline6pcm-\u003eproperties-\u003eplayback_hw.channels_max;\n 148:\t\tconst int frame_increment =\n 149:\t\t\tline6pcm-\u003eproperties-\u003erates.rats[0].num_min;\n 150:\t\tconst int frame_factor =\n 151:\t\t\tline6pcm-\u003eproperties-\u003erates.rats[0].den \n 152:\t\t\t(line6pcm-\u003eline6-\u003eintervals_per_second / LINE6_ISO_INTERVAL);\n 153:\t\tstruct urb urb_out;\n 154:\t\n 155:\t\tindex = find_first_zero_bit(\u0026line6pcm-\u003eout.active_urbs,\n 156:\t\t\t\t\t line6pcm-\u003eline6-\u003eiso_buffers);\n 157:\t\n 158:\t\tif (index \u003c 0 \|\| index \u003e= line6pcm-\u003eline6-\u003eiso_buffers) {\n 159:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"no free URB found\\n\");\n 160:\t\t\treturn -EINVAL;\n 161:\t\t}\n 162:\t\n 163:\t\turb_out = line6pcm-\u003eout.urbs[index];\n 164:\t\turb_size = 0;\n 165:\t\n 166:\t\t/* TODO: this may not work for LINE6_ISO_PACKETS != 1 /\n 167:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\n 168:\t\t\t/ compute frame size for given sampling rate /\n 169:\t\t\tint fsize = 0;\n 170:\t\t\tstruct usb_iso_packet_descriptor fout =\n 171:\t\t\t \u0026urb_out-\u003eiso_frame_desc[i];\n 172:\t\n 173:\t\t\tfsize = line6pcm-\u003eprev_fsize;\n 174:\t\t\tif (fsize == 0) {\n 175:\t\t\t\tint n;\n 176:\t\n 177:\t\t\t\tline6pcm-\u003eout.count += frame_increment;\n 178:\t\t\t\tn = line6pcm-\u003eout.count / frame_factor;\n 179:\t\t\t\tline6pcm-\u003eout.count -= n * frame_factor;\n 180:\t\t\t\tfsize = n;\n 181:\t\t\t}\n 182:\t\n 183:\t\t\tfsize = bytes_per_frame;\n 184:\t\t\tfsize = min(fsize, line6pcm-\u003emax_packet_size_out);\n 185:\t\n 186:\t\t\tfout-\u003eoffset = urb_size;\n 187:\t\t\tfout-\u003elength = fsize;\n 188:\t\t\turb_size += fsize;\n 189:\t\t}\n 190:\t\n 191:\t\tif (urb_size == 0) {\n 192:\t\t\t/ can't determine URB size /\n 193:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"driver bug: urb_size = 0\\n\");\n 194:\t\t\treturn -EINVAL;\n 195:\t\t}\n 196:\t\n 197:\t\turb_frames = urb_size / bytes_per_frame;\n 198:\t\turb_out-\u003etransfer_buffer =\n 199:\t\t line6pcm-\u003eout.buffer +\n 200:\t\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\n 201:\t\turb_out-\u003etransfer_buffer_length = urb_size;\n 202:\t\turb_out-\u003econtext = line6pcm;\n 203:\t\n 204:\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003eout.running) \u0026\u0026\n 205:\t\t !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, \u0026line6pcm-\u003eflags)) {\n 206:\t\t\tstruct snd_pcm_runtime runtime =\n 207:\t\t\t get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK)-\u003eruntime;\n 208:\t\n 209:\t\t\tif (line6pcm-\u003eout.pos + urb_frames \u003e runtime-\u003ebuffer_size) {\n 210:\t\t\t\t/\n 211:\t\t\t\t The transferred area goes over buffer boundary,\n 212:\t\t\t\t copy the data to the temp buffer.\n 213:\t\t\t\t /\n 214:\t\t\t\tint len;\n 215:\t\n 216:\t\t\t\tlen = runtime-\u003ebuffer_size - line6pcm-\u003eout.pos;\n 217:\t\n 218:\t\t\t\tif (len \u003e 0) {\n 219:\t\t\t\t\tmemcpy(urb_out-\u003etransfer_buffer,\n 220:\t\t\t\t\t runtime-\u003edma_area +\n 221:\t\t\t\t\t line6pcm-\u003eout.pos bytes_per_frame,\n 222:\t\t\t\t\t len * bytes_per_frame);\n 223:\t\t\t\t\tmemcpy(urb_out-\u003etransfer_buffer +\n 224:\t\t\t\t\t len * bytes_per_frame, runtime-\u003edma_area,\n 225:\t\t\t\t\t (urb_frames - len) * bytes_per_frame);\n 226:\t\t\t\t} else\n 227:\t\t\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"driver bug: len = %d\\n\",\n 228:\t\t\t\t\t\tlen);\n 229:\t\t\t} else {\n" }
35/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 4238 output: 38 thoughts: 15 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person: Diving into `submit_audio_out_urb` Right, let's drill down into `submit_audio_out_urb`. My initial thought is probably, "Okay, this is where the audio output chain likely hands off data to the USB subsystem." Given the context of audio, I'm expecting to see calls related to URB (USB Request Block) management. I'll need to figure out exactly how it's doing it. Is it using isochronous transfers? Bulk transfers with some kind of buffering? Or something more specialized, perhaps tied to a particular audio class driver? The specifics here will tell me a lot about the system's performance characteristics, latency profile, and power usage. I need to understand how the audio data itself is being formatted and packed into the URB, and how error conditions (like buffer underruns) are handled. Understanding this section will allow me to pinpoint potential bottlenecks and optimizations.
36/3	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 230, "LineCount": 50 } Results: { "Contents": " 230:\t\t\t\tmemcpy(urb_out-\u003etransfer_buffer,\n 231:\t\t\t\t runtime-\u003edma_area +\n 232:\t\t\t\t line6pcm-\u003eout.pos * bytes_per_frame,\n 233:\t\t\t\t urb_out-\u003etransfer_buffer_length);\n 234:\t\t\t}\n 235:\t\n 236:\t\t\tline6pcm-\u003eout.pos += urb_frames;\n 237:\t\t\tif (line6pcm-\u003eout.pos \u003e= runtime-\u003ebuffer_size)\n 238:\t\t\t\tline6pcm-\u003eout.pos -= runtime-\u003ebuffer_size;\n 239:\t\n 240:\t\t\tchange_volume(urb_out, line6pcm-\u003evolume_playback,\n 241:\t\t\t\t bytes_per_frame);\n 242:\t\t} else {\n 243:\t\t\tmemset(urb_out-\u003etransfer_buffer, 0,\n 244:\t\t\t urb_out-\u003etransfer_buffer_length);\n 245:\t\t}\n 246:\t\n 247:\t\tspin_lock_nested(\u0026line6pcm-\u003ein.lock, SINGLE_DEPTH_NESTING);\n 248:\t\tif (line6pcm-\u003eprev_fbuf) {\n 249:\t\t\tif (test_bit(LINE6_STREAM_IMPULSE, \u0026line6pcm-\u003eout.running)) {\n 250:\t\t\t\tcreate_impulse_test_signal(line6pcm, urb_out,\n 251:\t\t\t\t\t\t\t bytes_per_frame);\n 252:\t\t\t\tif (test_bit(LINE6_STREAM_PCM, \u0026line6pcm-\u003ein.running)) {\n 253:\t\t\t\t\tline6_capture_copy(line6pcm,\n 254:\t\t\t\t\t\t\t urb_out-\u003etransfer_buffer,\n 255:\t\t\t\t\t\t\t urb_out-\u003e\n 256:\t\t\t\t\t\t\t transfer_buffer_length);\n 257:\t\t\t\t\tline6_capture_check_period(line6pcm,\n 258:\t\t\t\t\t\turb_out-\u003etransfer_buffer_length);\n 259:\t\t\t\t}\n 260:\t\t\t} else {\n 261:\t\t\t\tif (!(line6pcm-\u003eline6-\u003eproperties-\u003ecapabilities \u0026 LINE6_CAP_HWMON)\n 262:\t\t\t\t \u0026\u0026 line6pcm-\u003eout.running \u0026\u0026 line6pcm-\u003ein.running)\n 263:\t\t\t\t\tadd_monitor_signal(urb_out, line6pcm-\u003eprev_fbuf,\n 264:\t\t\t\t\t\t\t line6pcm-\u003evolume_monitor,\n 265:\t\t\t\t\t\t\t bytes_per_frame);\n 266:\t\t\t}\n 267:\t\t\tline6pcm-\u003eprev_fbuf = NULL;\n 268:\t\t\tline6pcm-\u003eprev_fsize = 0;\n 269:\t\t}\n 270:\t\tspin_unlock(\u0026line6pcm-\u003ein.lock);\n 271:\t\n 272:\t\tret = usb_submit_urb(urb_out, GFP_ATOMIC);\n 273:\t\n 274:\t\tif (ret == 0)\n 275:\t\t\tset_bit(index, \u0026line6pcm-\u003eout.active_urbs);\n 276:\t\telse\n 277:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev,\n 278:\t\t\t\t\"URB out #%d submission failed (%d)\\n\", index, ret);\n 279:\t\n" }
37/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 5368 output: 29 thoughts: 263 Thoughts: Analyzing Potential Buffer Overflow in `submit_audio_out_urb` Okay, let's dissect this `submit_audio_out_urb` function. It looks like we're dealing with audio data output, probably using USB. My immediate concern is buffer overruns. The code allocates a buffer for each URB (`urb_out`) using `LINE6_ISO_PACKETS * line6pcm->max_packet_size_out` bytes. The crucial part is this line: ```c urb_out->transfer_buffer = line6pcm->out.buffer + index * LINE6_ISO_PACKETS * line6pcm->max_packet_size_out; ``` This suggests that `urb_out->transfer_buffer` is a slice within a larger buffer, `line6pcm->out.buffer`. Now, if the calculated frame size (`fsize` which is not shown, but referred to, I assume for the transfer size) is greater than `max_packet_size_out`, and the `index` variable is involved in the buffer calculation, we're staring at a potential buffer overflow. Specifically, `urb_size` could exceed the allocated space for a given URB. This means that when copying data into `urb_out->transfer_buffer` (via a `memcpy` or `memset` call, as is typical), it could either overrun the allocated space for this specific buffer (`LINE6_ISO_PACKETS * line6pcm->max_packet_size_out`), or, with a larger `index` value, write into memory that isn't allocated for this URB, potentially corrupting other parts of `line6pcm->out.buffer` or worse. The `index` variable gives me concern, since it suggests a loop, and repeated write operations. I'm going to track down where `line6pcm->out.buffer` is allocated to get a clearer picture of how big this buffer actually is and see how much the code trusts `max_packet_size_out`. I'll run a quick `grep` for "out.buffer" within the codebase to figure out its size and initialization. Let's see if we can trigger the issue.
38/3	2026/09/21 01:51	tool	grepper	0m Args: { "Expression": "out\\.buffer", "PathPrefix": "sound/usb/line6" } Results: { "Output": "sound/usb/line6/playback.c=140=static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-198-\turb_out-\u003etransfer_buffer =\nsound/usb/line6/playback.c:199:\t line6pcm-\u003eout.buffer +\nsound/usb/line6/playback.c-200-\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\n" }
39/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 6282 output: 28 thoughts: 16 Thoughts: Here's my summary, as if I were thinking these thoughts: Diving into the Line 6 PCM Code Okay, time to get to work. Based on the problem report, it's looking like the issue could be stemming from the audio driver for that Line 6 interface. Let's start digging into the code and see if we can identify the root cause. My instinct is to focus on the PCM aspects, so I'll start with the file path `sound/usb/line6/pcm.c`. That seems like the logical starting point. Let's see what we can find in there.
40/3	2026/09/21 01:51	tool	grepper	0m Args: { "Expression": "\\.buffer", "PathPrefix": "sound/usb/line6" } Results: { "Output": "sound/usb/line6/capture.c=21=static int submit_audio_in_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/capture.c-47-\turb_in-\u003etransfer_buffer =\nsound/usb/line6/capture.c:48:\t line6pcm-\u003ein.buffer +\nsound/usb/line6/capture.c-49-\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_in;\n--\nsound/usb/line6/playback.c=140=static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\n--\nsound/usb/line6/playback.c-198-\turb_out-\u003etransfer_buffer =\nsound/usb/line6/playback.c:199:\t line6pcm-\u003eout.buffer +\nsound/usb/line6/playback.c-200-\t index LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_out;\n--\nsound/usb/line6/pod.c=120=static struct line6_pcm_properties pod_pcm_properties = {\n--\nsound/usb/line6/pod.c-133-\t\t\t\t .channels_max = 2,\nsound/usb/line6/pod.c:134:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/pod.c-135-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/pod.c-150-\t\t\t\t .channels_max = 2,\nsound/usb/line6/pod.c:151:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/pod.c-152-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/pod.c=177=static void line6_pod_process_message(struct usb_line6 line6)\n--\nsound/usb/line6/pod.c-179-\tstruct usb_line6_pod pod = line6_to_pod(line6);\nsound/usb/line6/pod.c:180:\tconst unsigned char buf = pod-\u003eline6.buffer_message;\nsound/usb/line6/pod.c-181-\n--\nsound/usb/line6/podhd.c=57=static struct line6_pcm_properties podhd_pcm_properties = {\n--\nsound/usb/line6/podhd.c-70-\t\t\t\t .channels_max = 2,\nsound/usb/line6/podhd.c:71:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/podhd.c-72-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/podhd.c-87-\t\t\t\t .channels_max = 2,\nsound/usb/line6/podhd.c:88:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/podhd.c-89-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/podhd.c=99=static struct line6_pcm_properties podx3_pcm_properties = {\n--\nsound/usb/line6/podhd.c-112-\t\t\t\t .channels_max = 2,\nsound/usb/line6/podhd.c:113:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/podhd.c-114-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/podhd.c-132-\t\t\t\t .channels_max = 8,\nsound/usb/line6/podhd.c:133:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/podhd.c-134-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/toneport.c=73=static struct line6_pcm_properties toneport_pcm_properties = {\n--\nsound/usb/line6/toneport.c-86-\t\t\t\t .channels_max = 2,\nsound/usb/line6/toneport.c:87:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/toneport.c-88-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/toneport.c-103-\t\t\t\t .channels_max = 2,\nsound/usb/line6/toneport.c:104:\t\t\t\t .buffer_bytes_max = 60000,\nsound/usb/line6/toneport.c-105-\t\t\t\t .period_bytes_min = 64,\n--\nsound/usb/line6/variax.c=114=static void line6_variax_process_message(struct usb_line6 line6)\n--\nsound/usb/line6/variax.c-116-\tstruct usb_line6_variax variax = line6_to_variax(line6);\nsound/usb/line6/variax.c:117:\tconst unsigned char buf = variax-\u003eline6.buffer_message;\nsound/usb/line6/variax.c-118-\n" }
41/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 7833 output: 32 thoughts: 18 Thoughts: Here's my thought process, as requested: Tracing the Source of `snd_line6_pcm` Okay, so I need to figure out where the `snd_line6_pcm` variable or object is being defined or initialized in this audio driver. My approach is pretty standard here – I'm going to start by looking for its declaration. That probably means I'll be searching for a definition, whether it's a global variable, part of a structure, or possibly even allocated dynamically. I need to understand where this thing originates to understand its behavior and how it relates to the overall audio pipeline. Knowing its scope and initial state are crucial first steps. Let's dig in.
42/3	2026/09/21 01:51	tool	grepper	0m Args: { "Expression": "snd_line6_pcm", "PathPrefix": "sound/usb/line6" } Results: { "Output": "sound/usb/line6/capture.c-20-/\nsound/usb/line6/capture.c:21:static int submit_audio_in_urb(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-22-{\n--\nsound/usb/line6/capture.c-67-/\nsound/usb/line6/capture.c:68:int line6_submit_audio_in_all_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-69-{\n--\nsound/usb/line6/capture.c-83-/\nsound/usb/line6/capture.c:84:void line6_capture_copy(struct snd_line6_pcm line6pcm, char fbuf, int fsize)\nsound/usb/line6/capture.c-85-{\n--\nsound/usb/line6/capture.c-127-\nsound/usb/line6/capture.c:128:void line6_capture_check_period(struct snd_line6_pcm line6pcm, int length)\nsound/usb/line6/capture.c-129-{\n--\nsound/usb/line6/capture.c=145=static void audio_in_callback(struct urb urb)\n--\nsound/usb/line6/capture.c-147-\tint i, index, length = 0, shutdown = 0;\nsound/usb/line6/capture.c:148:\tstruct snd_line6_pcm line6pcm = (struct snd_line6_pcm )urb-\u003econtext;\nsound/usb/line6/capture.c-149-\n--\nsound/usb/line6/capture.c=215=static int snd_line6_capture_open(struct snd_pcm_substream substream)\n--\nsound/usb/line6/capture.c-218-\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\nsound/usb/line6/capture.c:219:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/capture.c-220-\n--\nsound/usb/line6/capture.c=234=static int snd_line6_capture_close(struct snd_pcm_substream substream)\nsound/usb/line6/capture.c-235-{\nsound/usb/line6/capture.c:236:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/capture.c-237-\n--\nsound/usb/line6/capture.c=243=const struct snd_pcm_ops snd_line6_capture_ops = {\n--\nsound/usb/line6/capture.c-252-\nsound/usb/line6/capture.c:253:int line6_create_audio_in_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/capture.c-254-{\n--\nsound/usb/line6/capture.h=16=extern const struct snd_pcm_ops snd_line6_capture_ops;\nsound/usb/line6/capture.h-17-\nsound/usb/line6/capture.h:18:extern void line6_capture_copy(struct snd_line6_pcm line6pcm, char fbuf,\nsound/usb/line6/capture.h-19-\t\t\t int fsize);\nsound/usb/line6/capture.h:20:extern void line6_capture_check_period(struct snd_line6_pcm line6pcm,\nsound/usb/line6/capture.h-21-\t\t\t\t int length);\nsound/usb/line6/capture.h:22:extern int line6_create_audio_in_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/capture.h:23:extern int line6_submit_audio_in_all_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/capture.h-24-\n--\nsound/usb/line6/driver.c=863=int line6_suspend(struct usb_interface interface, pm_message_t message)\n--\nsound/usb/line6/driver.c-865-\tstruct usb_line6 line6 = usb_get_intfdata(interface);\nsound/usb/line6/driver.c:866:\tstruct snd_line6_pcm line6pcm = line6-\u003eline6pcm;\nsound/usb/line6/driver.c-867-\n--\nsound/usb/line6/driver.h=119=struct usb_line6 {\n--\nsound/usb/line6/driver.h-145-\t/ Line 6 PCM device data structure /\nsound/usb/line6/driver.h:146:\tstruct snd_line6_pcm line6pcm;\nsound/usb/line6/driver.h-147-\n--\nsound/usb/line6/pcm.c=30=static int snd_line6_impulse_volume_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-32-{\nsound/usb/line6/pcm.c:33:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-34-\n--\nsound/usb/line6/pcm.c=39=static int snd_line6_impulse_volume_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-41-{\nsound/usb/line6/pcm.c:42:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-43-\tint value = ucontrol-\u003evalue.integer.value[0];\n--\nsound/usb/line6/pcm.c=73=static int snd_line6_impulse_period_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-75-{\nsound/usb/line6/pcm.c:76:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-77-\n--\nsound/usb/line6/pcm.c=82=static int snd_line6_impulse_period_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-84-{\nsound/usb/line6/pcm.c:85:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-86-\tint value = ucontrol-\u003evalue.integer.value[0];\n--\nsound/usb/line6/pcm.c-97-/\nsound/usb/line6/pcm.c:98:static void line6_unlink_audio_urbs(struct snd_line6_pcm line6pcm,\nsound/usb/line6/pcm.c-99-\t\t\t\t struct line6_pcm_stream pcms)\n--\nsound/usb/line6/pcm.c-113-/\nsound/usb/line6/pcm.c:114:static void line6_wait_clear_audio_urbs(struct snd_line6_pcm line6pcm,\nsound/usb/line6/pcm.c-115-\t\t\t\t\tstruct line6_pcm_stream pcms)\n--\nsound/usb/line6/pcm.c=137=static inline struct line6_pcm_stream \nsound/usb/line6/pcm.c:138:get_stream(struct snd_line6_pcm line6pcm, int direction)\nsound/usb/line6/pcm.c-139-{\n--\nsound/usb/line6/pcm.c-146- /\nsound/usb/line6/pcm.c:147:static int line6_buffer_acquire(struct snd_line6_pcm line6pcm,\nsound/usb/line6/pcm.c-148-\t\t\t\tstruct line6_pcm_stream pstr, int direction, int type)\n--\nsound/usb/line6/pcm.c-169- /\nsound/usb/line6/pcm.c:170:static void line6_buffer_release(struct snd_line6_pcm line6pcm,\nsound/usb/line6/pcm.c-171-\t\t\t\t struct line6_pcm_stream pstr, int type)\n--\nsound/usb/line6/pcm.c-181-/* start a PCM stream /\nsound/usb/line6/pcm.c:182:static int line6_stream_start(struct snd_line6_pcm line6pcm, int direction,\nsound/usb/line6/pcm.c-183-\t\t\t int type)\n--\nsound/usb/line6/pcm.c-204-/* stop a PCM stream; this doesn't sync with the unlinked URBs /\nsound/usb/line6/pcm.c:205:static void line6_stream_stop(struct snd_line6_pcm line6pcm, int direction,\nsound/usb/line6/pcm.c-206-\t\t\t int type)\n--\nsound/usb/line6/pcm.c=225=int snd_line6_trigger(struct snd_pcm_substream substream, int cmd)\nsound/usb/line6/pcm.c-226-{\nsound/usb/line6/pcm.c:227:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/pcm.c-228-\tstruct snd_pcm_substream s;\n--\nsound/usb/line6/pcm.c=287=snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream substream)\nsound/usb/line6/pcm.c-288-{\nsound/usb/line6/pcm.c:289:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/pcm.c-290-\tstruct line6_pcm_stream pstr = get_stream(line6pcm, substream-\u003estream);\n--\nsound/usb/line6/pcm.c-295-/* Stop and release duplex streams /\nsound/usb/line6/pcm.c:296:static void __line6_pcm_release(struct snd_line6_pcm line6pcm, int type)\nsound/usb/line6/pcm.c-297-{\n--\nsound/usb/line6/pcm.c-309-/* Stop and release duplex streams /\nsound/usb/line6/pcm.c:310:void line6_pcm_release(struct snd_line6_pcm line6pcm, int type)\nsound/usb/line6/pcm.c-311-{\n--\nsound/usb/line6/pcm.c=315=EXPORT_SYMBOL_GPL(line6_pcm_release);\n--\nsound/usb/line6/pcm.c-319- /\nsound/usb/line6/pcm.c:320:int line6_pcm_acquire(struct snd_line6_pcm line6pcm, int type, bool start)\nsound/usb/line6/pcm.c-321-{\n--\nsound/usb/line6/pcm.c=350=int snd_line6_hw_params(struct snd_pcm_substream substream,\n--\nsound/usb/line6/pcm.c-353-\tint ret;\nsound/usb/line6/pcm.c:354:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/pcm.c-355-\tstruct line6_pcm_stream pstr = get_stream(line6pcm, substream-\u003estream);\n--\nsound/usb/line6/pcm.c=368=int snd_line6_hw_free(struct snd_pcm_substream substream)\nsound/usb/line6/pcm.c-369-{\nsound/usb/line6/pcm.c:370:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/pcm.c-371-\tstruct line6_pcm_stream pstr = get_stream(line6pcm, substream-\u003estream);\n--\nsound/usb/line6/pcm.c=391=static int snd_line6_control_playback_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-394-\tint i;\nsound/usb/line6/pcm.c:395:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-396-\n--\nsound/usb/line6/pcm.c=404=static int snd_line6_control_playback_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pcm.c-407-\tint i, changed = 0;\nsound/usb/line6/pcm.c:408:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pcm.c-409-\n--\nsound/usb/line6/pcm.c=467=static void line6_cleanup_pcm(struct snd_pcm pcm)\nsound/usb/line6/pcm.c-468-{\nsound/usb/line6/pcm.c:469:\tstruct snd_line6_pcm line6pcm = snd_pcm_chip(pcm);\nsound/usb/line6/pcm.c-470-\n--\nsound/usb/line6/pcm.c=477=static int snd_line6_new_pcm(struct usb_line6 line6, struct snd_pcm pcm_ret)\n--\nsound/usb/line6/pcm.c-502-/\nsound/usb/line6/pcm.c:503:void line6_pcm_disconnect(struct snd_line6_pcm line6pcm)\nsound/usb/line6/pcm.c-504-{\n--\nsound/usb/line6/pcm.c=515=int line6_init_pcm(struct usb_line6 line6,\n--\nsound/usb/line6/pcm.c-521-\tstruct snd_pcm pcm;\nsound/usb/line6/pcm.c:522:\tstruct snd_line6_pcm line6pcm;\nsound/usb/line6/pcm.c-523-\n--\nsound/usb/line6/pcm.c=584=int snd_line6_prepare(struct snd_pcm_substream substream)\nsound/usb/line6/pcm.c-585-{\nsound/usb/line6/pcm.c:586:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/pcm.c-587-\tstruct line6_pcm_stream pstr = get_stream(line6pcm, substream-\u003estream);\n--\nsound/usb/line6/pcm.h=87=struct line6_pcm_stream {\n--\nsound/usb/line6/pcm.h-135-\nsound/usb/line6/pcm.h:136:struct snd_line6_pcm {\nsound/usb/line6/pcm.h-137-\t/ Pointer back to the Line 6 driver data structure /\n--\nsound/usb/line6/pcm.h=189=extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream substream);\nsound/usb/line6/pcm.h:190:extern void line6_pcm_disconnect(struct snd_line6_pcm line6pcm);\nsound/usb/line6/pcm.h:191:extern int line6_pcm_acquire(struct snd_line6_pcm line6pcm, int type,\nsound/usb/line6/pcm.h-192-\t\t\t bool start);\nsound/usb/line6/pcm.h:193:extern void line6_pcm_release(struct snd_line6_pcm line6pcm, int type);\nsound/usb/line6/pcm.h-194-\n--\nsound/usb/line6/playback.c=21=static void change_volume(struct urb urb_out, int volume[],\n--\nsound/usb/line6/playback.c-64-/\nsound/usb/line6/playback.c:65:static void create_impulse_test_signal(struct snd_line6_pcm line6pcm,\nsound/usb/line6/playback.c-66-\t\t\t\t struct urb urb_out, int bytes_per_frame)\n--\nsound/usb/line6/playback.c=108=static void add_monitor_signal(struct urb urb_out, unsigned char signal,\n--\nsound/usb/line6/playback.c-139-/\nsound/usb/line6/playback.c:140:static int submit_audio_out_urb(struct snd_line6_pcm line6pcm)\nsound/usb/line6/playback.c-141-{\n--\nsound/usb/line6/playback.c-286- /\nsound/usb/line6/playback.c:287:int line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/playback.c-288-{\n--\nsound/usb/line6/playback.c=303=static void audio_out_callback(struct urb urb)\n--\nsound/usb/line6/playback.c-306-\tunsigned long flags;\nsound/usb/line6/playback.c:307:\tstruct snd_line6_pcm line6pcm = (struct snd_line6_pcm )urb-\u003econtext;\nsound/usb/line6/playback.c-308-\tstruct snd_pcm_substream substream =\n--\nsound/usb/line6/playback.c=371=static int snd_line6_playback_open(struct snd_pcm_substream substream)\n--\nsound/usb/line6/playback.c-374-\tstruct snd_pcm_runtime runtime = substream-\u003eruntime;\nsound/usb/line6/playback.c:375:\tstruct snd_line6_pcm line6pcm = snd_pcm_substream_chip(substream);\nsound/usb/line6/playback.c-376-\n--\nsound/usb/line6/playback.c=393=const struct snd_pcm_ops snd_line6_playback_ops = {\n--\nsound/usb/line6/playback.c-402-\nsound/usb/line6/playback.c:403:int line6_create_audio_out_urbs(struct snd_line6_pcm line6pcm)\nsound/usb/line6/playback.c-404-{\n--\nsound/usb/line6/playback.h=26=extern const struct snd_pcm_ops snd_line6_playback_ops;\nsound/usb/line6/playback.h-27-\nsound/usb/line6/playback.h:28:extern int line6_create_audio_out_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/playback.h:29:extern int line6_submit_audio_out_all_urbs(struct snd_line6_pcm line6pcm);\nsound/usb/line6/playback.h-30-\n--\nsound/usb/line6/pod.c=326=static int snd_pod_control_monitor_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pod.c-328-{\nsound/usb/line6/pod.c:329:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pod.c-330-\tstruct usb_line6_pod pod = line6_to_pod(line6pcm-\u003eline6);\n--\nsound/usb/line6/pod.c=337=static int snd_pod_control_monitor_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/pod.c-339-{\nsound/usb/line6/pod.c:340:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/pod.c-341-\tstruct usb_line6_pod pod = line6_to_pod(line6pcm-\u003eline6);\n--\nsound/usb/line6/podhd.c=329=static int snd_podhd_control_monitor_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/podhd.c-331-{\nsound/usb/line6/podhd.c:332:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/podhd.c-333-\tstruct usb_line6_podhd podhd = line6_to_podhd(line6pcm-\u003eline6);\n--\nsound/usb/line6/podhd.c=340=static int snd_podhd_control_monitor_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/podhd.c-342-{\nsound/usb/line6/podhd.c:343:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/podhd.c-344-\tstruct usb_line6_podhd podhd = line6_to_podhd(line6pcm-\u003eline6);\n--\nsound/usb/line6/toneport.c=154=static int snd_toneport_monitor_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/toneport.c-156-{\nsound/usb/line6/toneport.c:157:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/toneport.c-158-\n--\nsound/usb/line6/toneport.c=164=static int snd_toneport_monitor_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/toneport.c-166-{\nsound/usb/line6/toneport.c:167:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/toneport.c-168-\tint err;\n--\nsound/usb/line6/toneport.c=209=static int snd_toneport_source_get(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/toneport.c-211-{\nsound/usb/line6/toneport.c:212:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/toneport.c-213-\tstruct usb_line6_toneport toneport = line6_to_toneport(line6pcm-\u003eline6);\n--\nsound/usb/line6/toneport.c=220=static int snd_toneport_source_put(struct snd_kcontrol kcontrol,\n--\nsound/usb/line6/toneport.c-222-{\nsound/usb/line6/toneport.c:223:\tstruct snd_line6_pcm line6pcm = snd_kcontrol_chip(kcontrol);\nsound/usb/line6/toneport.c-224-\tstruct usb_line6_toneport *toneport = line6_to_toneport(line6pcm-\u003eline6);\n" }
43/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14088 output: 38 thoughts: 35 Thoughts: Here's my take: Investigating the Line6 Audio Playback Okay, let's dive right in. The issue must be connected to how the audio data gets from the Line6 device to the system. Specifically, I need to check the function `line6_create_audio_out_urbs` at line 403 in `sound/usb/line6/playback.c`. That's where the critical connection happens – where the USB Request Blocks (URBs) are set up for audio output. This is the likely point of failure, or at least the point where the problem manifests. Let's see how they're being created and populated. I need to understand the data flow precisely, especially the URB setup. It all starts here, doesn't it?
44/3	2026/09/21 01:51	tool	read-file	0m Args: { "File": "sound/usb/line6/playback.c", "FirstLine": 400, "LineCount": 40 } Results: { "Contents": " 400:\t\t.pointer = snd_line6_pointer,\n 401:\t};\n 402:\t\n 403:\tint line6_create_audio_out_urbs(struct snd_line6_pcm line6pcm)\n 404:\t{\n 405:\t\tstruct usb_line6 line6 = line6pcm-\u003eline6;\n 406:\t\tint i;\n 407:\t\n 408:\t\tline6pcm-\u003eout.urbs = kzalloc_objs(struct urb , line6-\u003eiso_buffers);\n 409:\t\tif (line6pcm-\u003eout.urbs == NULL)\n 410:\t\t\treturn -ENOMEM;\n 411:\t\n 412:\t\t/ create audio URBs and fill in constant values: /\n 413:\t\tfor (i = 0; i \u003c line6-\u003eiso_buffers; ++i) {\n 414:\t\t\tstruct urb urb;\n 415:\t\n 416:\t\t\t/* URB for audio out: */\n 417:\t\t\turb = line6pcm-\u003eout.urbs[i] =\n 418:\t\t\t usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);\n 419:\t\n 420:\t\t\tif (urb == NULL)\n 421:\t\t\t\treturn -ENOMEM;\n 422:\t\n 423:\t\t\turb-\u003edev = line6-\u003eusbdev;\n 424:\t\t\turb-\u003epipe =\n 425:\t\t\t usb_sndisocpipe(line6-\u003eusbdev,\n 426:\t\t\t\t\t line6-\u003eproperties-\u003eep_audio_w \u0026\n 427:\t\t\t\t\t USB_ENDPOINT_NUMBER_MASK);\n 428:\t\t\turb-\u003etransfer_flags = URB_ISO_ASAP;\n 429:\t\t\turb-\u003estart_frame = -1;\n 430:\t\t\turb-\u003enumber_of_packets = LINE6_ISO_PACKETS;\n 431:\t\t\turb-\u003einterval = LINE6_ISO_INTERVAL;\n 432:\t\t\turb-\u003eerror_count = 0;\n 433:\t\t\turb-\u003ecomplete = audio_out_callback;\n 434:\t\t\tif (usb_urb_ep_type_check(urb))\n 435:\t\t\t\treturn -EINVAL;\n 436:\t\t}\n 437:\t\n 438:\t\treturn 0;\n 439:\t}\n" }
45/3	2026/09/21 01:51	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14953 output: 38 thoughts: 29 Thoughts: Okay, let's dive in. Checking `line6_buffer_acquire` Alright, time to get my hands dirty. I need to refresh my memory on the buffer acquisition process in the Line 6 USB audio driver. Specifically, I'm going to head straight for `sound/usb/line6/pcm.c:147` and take a look at the `line6_buffer_acquire` function. This is where the core interaction with the USB audio buffer happens, and understanding the nuances there is likely key to troubleshooting whatever I'm working on. I'll need to remember the typical flow, the locking mechanisms it uses, the error handling, and how it interacts with the DMA engine. Hopefully, this refresh will give me the insights I need.
46/3	2026/09/21 01:52	tool	read-file	0m Args: { "File": "sound/usb/line6/pcm.c", "FirstLine": 145, "LineCount": 40 } Results: { "Contents": " 145:\t * call this in line6pcm.state_mutex\n 146:\t /\n 147:\tstatic int line6_buffer_acquire(struct snd_line6_pcm line6pcm,\n 148:\t\t\t\t\tstruct line6_pcm_stream pstr, int direction, int type)\n 149:\t{\n 150:\t\tconst int pkt_size =\n 151:\t\t\t(direction == SNDRV_PCM_STREAM_PLAYBACK) ?\n 152:\t\t\t\tline6pcm-\u003emax_packet_size_out :\n 153:\t\t\t\tline6pcm-\u003emax_packet_size_in;\n 154:\t\n 155:\t\t/ Invoked multiple times in a row so allocate once only /\n 156:\t\tif (!test_and_set_bit(type, \u0026pstr-\u003eopened) \u0026\u0026 !pstr-\u003ebuffer) {\n 157:\t\t\tpstr-\u003ebuffer =\n 158:\t\t\t\tkmalloc(array3_size(line6pcm-\u003eline6-\u003eiso_buffers,\n 159:\t\t\t\t\t\t LINE6_ISO_PACKETS, pkt_size),\n 160:\t\t\t\t\tGFP_KERNEL);\n 161:\t\t\tif (!pstr-\u003ebuffer)\n 162:\t\t\t\treturn -ENOMEM;\n 163:\t\t}\n 164:\t\treturn 0;\n 165:\t}\n 166:\t\n 167:\t/ free a buffer if all streams are closed;\n 168:\t * call this in line6pcm.state_mutex\n 169:\t /\n 170:\tstatic void line6_buffer_release(struct snd_line6_pcm line6pcm,\n 171:\t\t\t\t\t struct line6_pcm_stream pstr, int type)\n 172:\t{\n 173:\t\tclear_bit(type, \u0026pstr-\u003eopened);\n 174:\t\tif (!pstr-\u003eopened) {\n 175:\t\t\tline6_wait_clear_audio_urbs(line6pcm, pstr);\n 176:\t\t\tkfree(pstr-\u003ebuffer);\n 177:\t\t\tpstr-\u003ebuffer = NULL;\n 178:\t\t}\n 179:\t}\n 180:\t\n 181:\t/ start a PCM stream /\n 182:\tstatic int line6_stream_start(struct snd_line6_pcm line6pcm, int direction,\n 183:\t\t\t\t int type)\n 184:\t{\n" }
47/3	2026/09/21 01:52	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15819 output: 37 thoughts: 492 Thoughts: Analyzing Potential USB Audio Buffer Overflow Okay, let's dive into this `line6_buffer_acquire` function. The key line here is the `kmalloc` call: it's allocating a buffer for the audio data, and the size is determined by `array3_size`, based on the number of `LINE6_ISO_PACKETS` and `pkt_size`, which comes from `line6pcm->max_packet_size_out`. Makes sense so far. Now, I'm turning my attention to `submit_audio_out_urb`. Specifically, the loop that calculates `fsize` (frame size). It looks like before this commit, there's a potential issue. The original code computes `fsize` and then uses it to determine the `transfer_buffer` offset and length. But, crucially, there's no limit. If the calculated `fsize` exceeds `max_packet_size_out`, the subsequent `memcpy` or `memset` operations could cause an out-of-bounds read or write. It’s a classic slab buffer overflow, yikes! My immediate question is: Is this a general issue or specific to the syzbot report that possibly triggered this fix? And does this affect capture as well? We need to make sure this fix is consistent across the driver. So, my next steps are to check the capture path for similar vulnerabilities. I'm going to search the Git history for analogous commits or dive into `sound/usb/line6/capture.c` to see if a comparable check exists there. Gotta be thorough. This is a critical area, so we need to be very sure the fix is complete.
48/3	2026/09/21 01:52	tool	read-file	0m Args: { "File": "sound/usb/line6/capture.c", "FirstLine": 20, "LineCount": 45 } Results: { "Contents": " 20:\t/\n 21:\tstatic int submit_audio_in_urb(struct snd_line6_pcm line6pcm)\n 22:\t{\n 23:\t\tint index;\n 24:\t\tint i, urb_size;\n 25:\t\tint ret;\n 26:\t\tstruct urb urb_in;\n 27:\t\n 28:\t\tindex = find_first_zero_bit(\u0026line6pcm-\u003ein.active_urbs,\n 29:\t\t\t\t\t line6pcm-\u003eline6-\u003eiso_buffers);\n 30:\t\n 31:\t\tif (index \u003c 0 \|\| index \u003e= line6pcm-\u003eline6-\u003eiso_buffers) {\n 32:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev, \"no free URB found\\n\");\n 33:\t\t\treturn -EINVAL;\n 34:\t\t}\n 35:\t\n 36:\t\turb_in = line6pcm-\u003ein.urbs[index];\n 37:\t\turb_size = 0;\n 38:\t\n 39:\t\tfor (i = 0; i \u003c LINE6_ISO_PACKETS; ++i) {\n 40:\t\t\tstruct usb_iso_packet_descriptor fin =\n 41:\t\t\t \u0026urb_in-\u003eiso_frame_desc[i];\n 42:\t\t\tfin-\u003eoffset = urb_size;\n 43:\t\t\tfin-\u003elength = line6pcm-\u003emax_packet_size_in;\n 44:\t\t\turb_size += line6pcm-\u003emax_packet_size_in;\n 45:\t\t}\n 46:\t\n 47:\t\turb_in-\u003etransfer_buffer =\n 48:\t\t line6pcm-\u003ein.buffer +\n 49:\t\t index * LINE6_ISO_PACKETS * line6pcm-\u003emax_packet_size_in;\n 50:\t\turb_in-\u003etransfer_buffer_length = urb_size;\n 51:\t\turb_in-\u003econtext = line6pcm;\n 52:\t\n 53:\t\tret = usb_submit_urb(urb_in, GFP_ATOMIC);\n 54:\t\n 55:\t\tif (ret == 0)\n 56:\t\t\tset_bit(index, \u0026line6pcm-\u003ein.active_urbs);\n 57:\t\telse\n 58:\t\t\tdev_err(line6pcm-\u003eline6-\u003eifcdev,\n 59:\t\t\t\t\"URB in #%d submission failed (%d)\\n\", index, ret);\n 60:\t\n 61:\t\treturn 0;\n 62:\t}\n 63:\t\n 64:\t/*\n" }
49/3	2026/09/21 01:52	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 17370 output: 272 thoughts: 1959 Thoughts: Analysis of a USB Audio Driver Patch: KMSAN Applicability Okay, let's break this down. I'm looking at a patch in `sound/usb/line6/playback.c` that seems to be fixing a potential buffer overflow vulnerability. The core issue is that `fsize`, the size of data being written to a USB transfer buffer (`urb_out->transfer_buffer`), was being calculated dynamically. This could, in some cases, exceed the buffer's allocated size (`line6pcm->max_packet_size_out` multiplied by `LINE6_ISO_PACKETS`), leading to writes outside of the buffer boundary during operations like `memcpy`, `memset`, or volume adjustments. This could cause issues when submitting the URB to the USB host controller. The patch introduces a `min()` operation: `fsize = min(fsize, line6pcm->max_packet_size_out);`. This essentially clamps `fsize`, ensuring it never exceeds the buffer's capacity. Good. This is a classic bounds check and, therefore, good practice. Now, my primary concern, as always, is whether this change introduces any uninitialized memory risks. Let's analyze. The patch itself doesn't directly create new data structures, introduce conditional logic based on uninitialized variables, or send uninitialized data to userspace. The critical part is how `fsize` and the subsequent `urb_size` are used after the clamp. I meticulously traced how those variables are used: they're involved in calculating offsets and lengths for `memcpy` operations from the user-space DMA area to the `urb_out->transfer_buffer` or when the buffer is cleared. The important thing to consider is whether this clamping might lead to reading uninitialized memory in the `transfer_buffer`. It doesn't. Before transmission, the entire `transfer_buffer` is always initialized, either by a `memcpy` from the user-space DMA buffer, or by a `memset`. The key here is that the problem before the patch was an out-of-bounds write. This patch fixes that write, as now `urb_size` is always within the bounds of `pstr->buffer`. Thus, clamping `fsize` prevents out-of-bounds slab access. Given this, the KMSAN (Kernel Memory Sanitizer) consideration is straightforward. KMSAN is primarily for catching uninitialized memory usage and information leaks to user space. This patch primarily addresses an out-of-bounds memory access issue, which is precisely what KASAN (Kernel Address Sanitizer) excels at detecting. There is no new risk of uninitialized memory access here; the patch removes a bug that could be triggered by KASAN. Therefore, `NeedsKMSAN` should be set to `false`. KASAN is sufficient for this. The KMSAN reasoning is: this patch adds a simple bounds check to prevent out-of-bounds writes during USB audio playback. This fixes a buffer overflow, which is a KASAN issue, and it does not introduce any risks of uninitialized memory usage, nor does it create any information leaks.
50/3	2026/09/21 01:52	tool	set-results	0m Args: { "KMSANReasoning": "The patch adds a bounds check (`fsize = min(fsize, line6pcm-\u003emax_packet_size_out)`) in `submit_audio_out_urb()` in `sound/usb/line6/playback.c`. \n\nPrior to this fix, if `fsize` exceeded `max_packet_size_out`, the cumulative `urb_size` could exceed the buffer allocated for each URB (`LINE6_ISO_PACKETS * max_packet_size_out`), resulting in slab out-of-bounds reads/writes during `memcpy()`, `memset()`, or USB transmission. Out-of-bounds accesses and buffer overflows are explicitly within the domain of KASAN, not KMSAN.\n\nThe patch does not introduce new allocations, does not read or branch on uninitialized variables, does not expose kernel memory to user space (info-leak), and does not cause surrounding code to read uninitialized buffer bytes. The buffer contents are explicitly populated either from the PCM runtime DMA buffer or zeroed with `memset()` for the full length of the transfer. Therefore, standard KASAN fuzzing is sufficient and a dedicated KMSAN session is not required.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch adds a bounds check (`fsize = min(fsize, line6pcm-\u003emax_packet_size_out)`) in `submit_audio_out_urb()` in `sound/usb/line6/playback.c`. \n\nPrior to this fix, if `fsize` exceeded `max_packet_size_out`, the cumulative `urb_size` could exceed the buffer allocated for each URB (`LINE6_ISO_PACKETS * max_packet_size_out`), resulting in slab out-of-bounds reads/writes during `memcpy()`, `memset()`, or USB transmission. Out-of-bounds accesses and buffer overflows are explicitly within the domain of KASAN, not KMSAN.\n\nThe patch does not introduce new allocations, does not read or branch on uninitialized variables, does not expose kernel memory to user space (info-leak), and does not cause surrounding code to read uninitialized buffer bytes. The buffer contents are explicitly populated either from the PCM runtime DMA buffer or zeroed with `memset()` for the full length of the transfer. Therefore, standard KASAN fuzzing is sufficient and a dedicated KMSAN session is not required.", "NeedsKMSAN": false }

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