AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/09/19 01:36	flow	patch-triage	9m Args: null Results: { "EnableConfigs": [ "BPF_SYSCALL", "USERFAULTFD", "NTSYNC", "AF_KCM", "XFS_FS", "NET_HANDSHAKE", "MEDIA_SUPPORT", "MEDIA_CONTROLLER", "GPIOLIB", "GPIO_CDEV", "GPIO_CDEV_V1" ], "FocusSymbols": [ "receive_fd", "scm_recv_one_fd", "bpf_iter_new_fd", "bpf_token_create", "xfs_open_by_handle", "media_request_alloc", "handshake_nl_accept_doit", "kcm_ioctl", "ntsync_obj_get_fd" ], "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false, "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.", "WorthFuzzing": true }
1/1	2026/09/19 01:36	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 58a61ff73c4736b57ba577d0b474d08304b94c83\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Sat Sep 19 01:36:27 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c\nindex 2b54afb31529f..5c06f69c9f7f9 100644\n--- a/arch/powerpc/platforms/cell/spufs/inode.c\n+++ b/arch/powerpc/platforms/cell/spufs/inode.c\n@@ -266,9 +266,9 @@ spufs_mkdir(struct inode dir, struct dentry dentry, unsigned int flags,\n static int spufs_context_open(const struct path path)\n {\n \tFD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tfd_prepare_file(fdf)-\u003ef_op = \u0026spufs_context_fops;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tfdf-\u003efile-\u003ef_op = \u0026spufs_context_fops;\n \treturn fd_publish(fdf);\n }\n \n@@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path path)\n \t * in error path of _open().\n \t /\n \tFD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tfd_prepare_file(fdf)-\u003ef_op = \u0026spufs_gang_fops;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tfdf-\u003efile-\u003ef_op = \u0026spufs_gang_fops;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c\nindex 9f3b628d57934..6526ce27ea446 100644\n--- a/drivers/gpio/gpiolib-cdev.c\n+++ b/drivers/gpio/gpiolib-cdev.c\n@@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device gdev, void __user ip)\n \tFD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC,\n \t\t anon_inode_getfile(\"gpio-linehandle\", \u0026linehandle_fileops,\n \t\t\t\t lh, O_RDONLY \| O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(lh);\n \n-\thandlereq.fd = fd_prepare_fd(fdf);\n+\thandlereq.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026handlereq, sizeof(handlereq)))\n \t\treturn -EFAULT;\n \n@@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device gdev, void __user ip)\n \tFD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC,\n \t\t anon_inode_getfile(\"gpio-line\", \u0026line_fileops, lr,\n \t\t\t\t O_RDONLY \| O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(lr);\n \n-\tulr.fd = fd_prepare_fd(fdf);\n+\tulr.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026ulr, sizeof(ulr)))\n \t\treturn -EFAULT;\n \n@@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device gdev, void __user ip)\n \tFD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC,\n \t\t anon_inode_getfile(\"gpio-event\", \u0026lineevent_fileops, le,\n \t\t\t\t O_RDONLY \| O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(le);\n \n-\teventreq.fd = fd_prepare_fd(fdf);\n+\teventreq.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026eventreq, sizeof(eventreq)))\n \t\treturn -EFAULT;\n \ndiff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c\nindex ce65b1160955e..7fa2e858bd082 100644\n--- a/drivers/gpu/drm/msm/msm_perfcntr.c\n+++ b/drivers/gpu/drm/msm/msm_perfcntr.c\n@@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device dev, void data, struct drm_file f\n \n \t\tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t\t anon_inode_getfile(\"[msm_perfcntrs]\", \u0026stream_fops, stream, 0));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \n \t\tINIT_WORK(\u0026stream-\u003esel_work, sel_worker);\n \t\tkthread_init_work(\u0026stream-\u003esample_work, sample_worker);\ndiff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c\nindex 13e77648807c2..e1387f039780b 100644\n--- a/drivers/media/mc/mc-request.c\n+++ b/drivers/media/mc/mc-request.c\n@@ -316,15 +316,15 @@ int media_request_alloc(struct media_device mdev, int alloc_fd)\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t anon_inode_getfile(\"request\", \u0026request_fops, NULL,\n \t\t\t\t O_CLOEXEC));\n-\tif (fdf.err) {\n-\t\tret = fdf.err;\n+\tif (fdf-\u003efd \u003c 0) {\n+\t\tret = fdf-\u003efd;\n \t\tgoto err_free_req;\n \t}\n \n-\tfd_prepare_file(fdf)-\u003eprivate_data = req;\n+\tfdf-\u003efile-\u003eprivate_data = req;\n \n \tsnprintf(req-\u003edebug_str, sizeof(req-\u003edebug_str), \"%u:%d\",\n-\t\t atomic_inc_return(\u0026mdev-\u003erequest_id), fd_prepare_fd(fdf));\n+\t\t atomic_inc_return(\u0026mdev-\u003erequest_id), fdf-\u003efd);\n \tatomic_inc(\u0026mdev-\u003enum_requests);\n \tdev_dbg(mdev-\u003edev, \"request: allocated %s\\n\", req-\u003edebug_str);\n \ndiff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c\nindex 4a805919bb0c5..2857ae37d3c81 100644\n--- a/drivers/misc/ntsync.c\n+++ b/drivers/misc/ntsync.c\n@@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj obj)\n {\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t anon_inode_getfile(\"ntsync\", \u0026ntsync_obj_fops, obj, O_RDWR));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tobj-\u003efile = fd_prepare_file(fdf);\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tobj-\u003efile = fdf-\u003efile;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/fs/eventfd.c b/fs/eventfd.c\nindex 9d33a02757d52..52426795752ec 100644\n--- a/fs/eventfd.c\n+++ b/fs/eventfd.c\n@@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags)\n \tFD_PREPARE(fdf, flags,\n \t\t anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n \t\t\t\t\t flags, FMODE_NOWAIT));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tctx-\u003eid = ida_alloc(\u0026eventfd_ida, GFP_KERNEL);\n \tretain_and_null_ptr(ctx);\ndiff --git a/fs/eventpoll.c b/fs/eventpoll.c\nindex e0c4bf88a8383..f48b829a710f7 100644\n--- a/fs/eventpoll.c\n+++ b/fs/eventpoll.c\n@@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags)\n \tFD_PREPARE(fdf, O_RDWR \| (flags \u0026 O_CLOEXEC),\n \t\t anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n \t\t\t\t O_RDWR \| (flags \u0026 O_CLOEXEC)));\n-\tif (fdf.err) {\n+\tif (fdf-\u003efd \u003c 0) {\n \t\tep_clear_and_put(ep);\n-\t\treturn fdf.err;\n+\t\treturn fdf-\u003efd;\n \t}\n-\tep-\u003efile = fd_prepare_file(fdf);\n+\tep-\u003efile = fdf-\u003efile;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/fs/file.c b/fs/file.c\nindex 628ca07dc4b17..2a01b22eb65a1 100644\n--- a/fs/file.c\n+++ b/fs/file.c\n@@ -1391,17 +1391,17 @@ int receive_fd(struct file file, int __user ufd, unsigned int o_flags)\n \t\treturn error;\n \n \tFD_PREPARE(fdf, o_flags, file);\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tget_file(file);\n \n \tif (ufd) {\n-\t\terror = put_user(fd_prepare_fd(fdf), ufd);\n+\t\terror = put_user(fdf-\u003efd, ufd);\n \t\tif (error)\n \t\t\treturn error;\n \t}\n \n-\t__receive_sock(fd_prepare_file(fdf));\n+\t__receive_sock(fdf-\u003efile);\n \treturn fd_publish(fdf);\n }\n EXPORT_SYMBOL_GPL(receive_fd);\ndiff --git a/fs/namespace.c b/fs/namespace.c\nindex 1ecd96c918b33..0f5c00816775b 100644\n--- a/fs/namespace.c\n+++ b/fs/namespace.c\n@@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n \n \tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\n \t\t dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n-\tif (fdf.err) {\n+\tif (fdf-\u003efd \u003c 0) {\n \t\tdissolve_on_fput(new_path.mnt);\n-\t\treturn fdf.err;\n+\t\treturn fdf-\u003efd;\n \t}\n \n \t/\n \t Attach to an apparent O_PATH fd with a note that we\n \t * need to unmount it, not just simply put it.\n \t /\n-\tfd_prepare_file(fdf)-\u003ef_mode \|= FMODE_NEED_UNMOUNT;\n+\tfdf-\u003efile-\u003ef_mode \|= FMODE_NEED_UNMOUNT;\n \treturn fd_publish(fdf);\n }\n \n@@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user , filename,\n \t\treturn -EINVAL;\n \n \tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tif (uattr) {\n \t\tstruct mount_kattr kattr = {};\n-\t\tstruct file file = fd_prepare_file(fdf);\n+\t\tstruct file file = fdf-\u003efile;\n \t\tint ret;\n \n \t\tif (flags \u0026 OPEN_TREE_CLONE)\ndiff --git a/fs/nsfs.c b/fs/nsfs.c\nindex c3b6ae76594a8..56ea0bb9ef3a3 100644\n--- a/fs/nsfs.c\n+++ b/fs/nsfs.c\n@@ -348,8 +348,8 @@ static long ns_ioctl(struct file filp, unsigned int ioctl,\n \t\t\treturn ret;\n \n \t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \t\t/\n \t\t * If @uinfo is passed return all information about the\n \t\t * mount namespace as well.\ndiff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c\nindex 0689cade8f74c..303bcff644596 100644\n--- a/fs/xfs/xfs_handle.c\n+++ b/fs/xfs/xfs_handle.c\n@@ -272,11 +272,11 @@ xfs_open_by_handle(\n \tpath.mnt = mntget(parfilp-\u003ef_path.mnt);\n \n \tFD_PREPARE(fdf, 0, dentry_open(\u0026path, hreq-\u003eoflags, cred));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tif (S_ISREG(inode-\u003ei_mode)) {\n-\t\tstruct file filp = fd_prepare_file(fdf);\n+\t\tstruct file filp = fdf-\u003efile;\n \n \t\tfilp-\u003ef_flags \|= O_NOATIME;\n \t\tfilp-\u003ef_mode \|= FMODE_NOCMTIME;\ndiff --git a/include/linux/cleanup.h b/include/linux/cleanup.h\nindex b1b5698cbf1b6..1fb8058b897d4 100644\n--- a/include/linux/cleanup.h\n+++ b/include/linux/cleanup.h\n@@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void val)\n CLASS(name, var)(args...):\n \tdeclare the variable @var as an instance of the named class\n \n- * CLASS_INIT(name, var, init_expr):\n- \tdeclare the variable @var as an instance of the named class with\n- \tcustom initialization expression.\n- \n Ex.\n \n DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd)\n@@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_\n \tclass_##_name##_t var __cleanup(class_##_name##_destructor) =\t\\\n \t\tclass_##_name##_constructor\n \n-#define CLASS_INIT(_name, _var, _init_expr) \\\n- class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr)\n-\n #define __scoped_class(_name, var, _label, args...) \\\n \tfor (CLASS(_name, var)(args); ; ({ goto _label; })) \\\n \t\tif (0) { \\\ndiff --git a/include/linux/file.h b/include/linux/file.h\nindex 27484b444d315..41c3c0be10644 100644\n--- a/include/linux/file.h\n+++ b/include/linux/file.h\n@@ -12,6 +12,7 @@\n #include \u003clinux/errno.h\u003e\n #include \u003clinux/cleanup.h\u003e\n #include \u003clinux/err.h\u003e\n+#include \u003clinux/vfsdebug.h\u003e\n \n struct file;\n \n@@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;\n \n /\n fd_prepare: Combined fd + file allocation cleanup class.\n- * @err: Error code to indicate if allocation succeeded.\n- * @__fd: Allocated fd (may not be accessed directly)\n- * @__file: Allocated struct file pointer (may not be accessed directly)\n+ * @fd: Allocated fd\n+ * @file: Allocated struct file pointer\n \n Allocates an fd and a file together. On error paths, automatically cleans\n * up whichever resource was successfully allocated. Allows flexible file\n * allocation with different functions per usage.\n \n- Do not use directly.\n+ * Do not declare directly, use FD_PREPARE().\n /\n struct fd_prepare {\n-\ts32 err;\n-\ts32 __fd; / do not access directly /\n-\tstruct file __file; /* do not access directly /\n+\tint fd;\n+\tstruct file file;\n };\n \n-/* Typedef for fd_prepare cleanup guards. /\n-typedef struct fd_prepare class_fd_prepare_t;\n-\n-/\n- * Accessors for fd_prepare class members.\n- * _Generic() is used for zero-cost type safety.\n- /\n-#define fd_prepare_fd(_fdf) \\\n-\t(_Generic((_fdf), struct fd_prepare: (_fdf).__fd))\n-\n-#define fd_prepare_file(_fdf) \\\n-\t(_Generic((_fdf), struct fd_prepare: (_fdf).__file))\n-\n / Do not use directly. /\n-static inline void class_fd_prepare_destructor(const struct fd_prepare fdf)\n+static __always_inline void __fd_prepare_cleanup(const struct fd_prepare fdf)\n {\n-\tif (unlikely(fdf-\u003e__fd \u003e= 0))\n-\t\tput_unused_fd(fdf-\u003e__fd);\n-\tif (unlikely(!IS_ERR_OR_NULL(fdf-\u003e__file)))\n-\t\tfput(fdf-\u003e__file);\n+\tif (unlikely(fdf-\u003efd \u003e= 0)) {\n+\t\tput_unused_fd(fdf-\u003efd);\n+\t\tfput(fdf-\u003efile);\n+\t}\n }\n \n / Do not use directly. /\n-static inline int class_fd_prepare_lock_err(const struct fd_prepare fdf)\n+static __always_inline struct fd_prepare __fd_prepare(int fd, struct file file)\n {\n-\tif (unlikely(fdf-\u003eerr))\n-\t\treturn fdf-\u003eerr;\n-\tif (unlikely(fdf-\u003e__fd \u003c 0))\n-\t\treturn fdf-\u003e__fd;\n-\tif (unlikely(IS_ERR(fdf-\u003e__file)))\n-\t\treturn PTR_ERR(fdf-\u003e__file);\n-\tif (unlikely(!fdf-\u003e__file))\n-\t\treturn -ENOMEM;\n-\treturn 0;\n+\tif (fd \u003e= 0 \u0026\u0026 IS_ERR_OR_NULL(file)) {\n+\t\tint err = file ? PTR_ERR(file) : -ENOMEM;\n+\n+\t\tput_unused_fd(fd);\n+\t\tfd = err;\n+\t\tfile = NULL;\n+\t}\n+\treturn (struct fd_prepare){ .fd = fd, .file = file };\n }\n \n /\n- * __FD_PREPARE_INIT - Helper to initialize fd_prepare class.\n- * @_fd_flags: flags for get_unused_fd_flags()\n- * @_file_owned: expression that returns struct file \n- \n- * Returns a struct fd_prepare with fd, file, and err set.\n- * If fd allocation fails, fd will be negative and err will be set. If\n- * fd succeeds but file_init_expr fails, file will be ERR_PTR and err\n- * will be set. The err field is the single source of truth for error\n- * checking.\n- /\n-#define __FD_PREPARE_INIT(_fd_flags, _file_owned) \\\n-\t({ \\\n-\t\tstruct fd_prepare fdf = { \\\n-\t\t\t.__fd = get_unused_fd_flags((_fd_flags)), \\\n-\t\t}; \\\n-\t\tif (likely(fdf.__fd \u003e= 0)) \\\n-\t\t\tfdf.__file = (_file_owned); \\\n-\t\tfdf.err = ACQUIRE_ERR(fd_prepare, \u0026fdf); \\\n-\t\tfdf; \\\n-\t})\n-\n-/\n- * FD_PREPARE - Macro to declare and initialize an fd_prepare variable.\n+ * FD_PREPARE - Declare and initialize an fd_prepare instance.\n \n- Declares and initializes an fd_prepare variable with automatic\n- * cleanup. No separate scope required - cleanup happens when variable\n- * goes out of scope.\n+ * This allocates a new fd and only evaluates @_file_owned if the\n+ * allocation succeeded. Cleanup happens when the variable goes out of\n+ * scope and the guard releases whichever of the descriptor and the file\n+ * was allocated. If fd_publish() was called the fd and file are\n+ * published and cleanup becomes a nop.\n \n- @_fdf: name of struct fd_prepare variable to define\n+ * @_fdf: name of the const struct fd_prepare pointer to define\n * @_fd_flags: flags for get_unused_fd_flags()\n * @_file_owned: struct file to take ownership of (can be expression)\n /\n+#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)\t\t\\\n+\tstruct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({\t\\\n+\t\tint __fd = get_unused_fd_flags(_fd_flags);\t\t\\\n+\t\t__fd_prepare(__fd, __fd \u003c 0 ? NULL : (_file_owned));\t\\\n+\t});\t\t\t\t\t\t\t\t\\\n+\tconst struct fd_prepare const _fdf = \u0026_guard\n+\n #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \\\n-\tCLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))\n+\t__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)\n \n /\n fd_publish - Publish prepared fd and file to the fd table.\n- * @_fdf: struct fd_prepare variable\n+ * @fdf: struct fd_prepare pointer defined by FD_PREPARE()\n /\n-#define fd_publish(_fdf) \\\n-\t({ \\\n-\t\tstruct fd_prepare fdp = \u0026(_fdf); \\\n-\t\tVFS_WARN_ON_ONCE(fdp-\u003eerr); \\\n-\t\tVFS_WARN_ON_ONCE(fdp-\u003e__fd \u003c 0); \\\n-\t\tVFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp-\u003e__file)); \\\n-\t\tfd_install(fdp-\u003e__fd, fdp-\u003e__file); \\\n-\t\tretain_and_null_ptr(fdp-\u003e__file); \\\n-\t\ttake_fd(fdp-\u003e__fd); \\\n-\t})\n+static __always_inline int fd_publish(const struct fd_prepare fdf)\n+{\n+\t/ Callers only get a const view, the guard itself is writable. /\n+\tstruct fd_prepare guard = (struct fd_prepare )fdf;\n+\n+\tVFS_WARN_ON_ONCE(guard-\u003efd \u003c 0);\n+\tfd_install(guard-\u003efd, guard-\u003efile);\n+\treturn take_fd(guard-\u003efd);\n+}\n \n / Do not use directly. /\n-#define __FD_ADD(_fdf, _fd_flags, _file_owned) \\\n-\t({ \\\n-\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned); \\\n-\t\ts32 ret = _fdf.err; \\\n-\t\tif (likely(!ret)) \\\n-\t\t\tret = fd_publish(_fdf); \\\n-\t\tret; \\\n+#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\n+\t({\t\t\t\t\t\t\t\\\n+\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned);\t\\\n+\t\t_fdf-\u003efd \u003c 0 ? _fdf-\u003efd : fd_publish(_fdf);\t\\\n \t})\n \n /\ndiff --git a/io_uring/mock_file.c b/io_uring/mock_file.c\nindex b318ed697998e..9f0b4d850c12f 100644\n--- a/io_uring/mock_file.c\n+++ b/io_uring/mock_file.c\n@@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd cmd, unsigned int issue_flag\n \tFD_PREPARE(fdf, O_RDWR \| O_CLOEXEC,\n \t\t anon_inode_create_getfile(\"[io_uring_mock]\", fops, mf,\n \t\t\t\t\t O_RDWR \| O_CLOEXEC, NULL));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tretain_and_null_ptr(mf);\n-\tfile = fd_prepare_file(fdf);\n+\tfile = fdf-\u003efile;\n \tfile-\u003ef_mode \|= FMODE_READ \| FMODE_CAN_READ \| FMODE_WRITE \|\n \t\t\tFMODE_CAN_WRITE \| FMODE_LSEEK;\n \tif (mc.flags \u0026 IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)\n \t\tfile-\u003ef_mode \|= FMODE_NOWAIT;\n \n-\tmc.out_fd = fd_prepare_fd(fdf);\n+\tmc.out_fd = fdf-\u003efd;\n \tif (copy_to_user(uarg, \u0026mc, uarg_size))\n \t\treturn -EFAULT;\n \ndiff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c\nindex 14a5fdfa04214..5f790d12f72e1 100644\n--- a/kernel/bpf/bpf_iter.c\n+++ b/kernel/bpf/bpf_iter.c\n@@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link link)\n \tflags = O_RDONLY \| O_CLOEXEC;\n \n \tFD_PREPARE(fdf, flags, anon_inode_getfile(\"bpf_iter\", \u0026bpf_iter_fops, NULL, flags));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \titer_link = container_of(link, struct bpf_iter_link, link);\n-\terr = prepare_seq_file(fd_prepare_file(fdf), iter_link);\n+\terr = prepare_seq_file(fdf-\u003efile, iter_link);\n \tif (err)\n \t\treturn err; /* Automatic cleanup handles fput /\n \ndiff --git a/kernel/bpf/token.c b/kernel/bpf/token.c\nindex e85a179523f02..da915a4f972b1 100644\n--- a/kernel/bpf/token.c\n+++ b/kernel/bpf/token.c\n@@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr attr)\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME,\n \t\t\t\t O_RDWR, \u0026bpf_token_fops));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \ttoken = kzalloc_obj(token, GFP_USER);\n \tif (!token)\n@@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr attr)\n \t\treturn err;\n \n \tget_user_ns(token-\u003euserns);\n-\tfd_prepare_file(fdf)-\u003eprivate_data = no_free_ptr(token);\n+\tfdf-\u003efile-\u003eprivate_data = no_free_ptr(token);\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/mm/userfaultfd.c b/mm/userfaultfd.c\nindex 23fb68fce000e..ea382aedfc90d 100644\n--- a/mm/userfaultfd.c\n+++ b/mm/userfaultfd.c\n@@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags)\n \t\t anon_inode_create_getfile(\"[userfaultfd]\", \u0026userfaultfd_fops, ctx,\n \t\t\t\t\t O_RDONLY \| (flags \u0026 UFFD_SHARED_FCNTL_FLAGS),\n \t\t\t\t\t NULL));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \t/* prevent the mm struct to be freed /\n \tmmgrab(ctx-\u003emm);\n-\tfd_prepare_file(fdf)-\u003ef_mode \|= FMODE_NOWAIT;\n+\tfdf-\u003efile-\u003ef_mode \|= FMODE_NOWAIT;\n \tretain_and_null_ptr(ctx);\n \treturn fd_publish(fdf);\n }\ndiff --git a/net/core/scm.c b/net/core/scm.c\nindex f0d44ecdb11fc..15c330784a699 100644\n--- a/net/core/scm.c\n+++ b/net/core/scm.c\n@@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file f, int __user ufd, unsigned int flags,\n \t\treturn notrunc ? put_user(error, ufd) : error;\n \n \tFD_PREPARE(fdf, flags, get_file(f));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n-\terror = put_user(fd_prepare_fd(fdf), ufd);\n+\terror = put_user(fdf-\u003efd, ufd);\n \tif (error)\n \t\treturn error;\n \n-\t__receive_sock(fd_prepare_file(fdf));\n+\t__receive_sock(fdf-\u003efile);\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/net/handshake/netlink.c b/net/handshake/netlink.c\nindex 3fd4fef9bab1a..73b8314d9010c 100644\n--- a/net/handshake/netlink.c\n+++ b/net/handshake/netlink.c\n@@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff skb, struct genl_info info)\n \treq = handshake_req_next(hn, class);\n \tif (req) {\n \t\tFD_PREPARE(fdf, O_CLOEXEC, req-\u003ehr_file);\n-\t\tif (fdf.err) {\n+\t\tif (fdf-\u003efd \u003c 0) {\n \t\t\tfput(req-\u003ehr_file); / drop ref from handshake_req_next() /\n-\t\t\terr = fdf.err;\n+\t\t\terr = fdf-\u003efd;\n \t\t\tgoto out_complete;\n \t\t}\n \n-\t\terr = req-\u003ehr_proto-\u003ehp_accept(req, info, fd_prepare_fd(fdf));\n+\t\terr = req-\u003ehr_proto-\u003ehp_accept(req, info, fdf-\u003efd);\n \t\tif (err)\n \t\t\tgoto out_complete; / Automatic cleanup handles fput /\n \n-\t\ttrace_handshake_cmd_accept(net, req, req-\u003ehr_sk, fd_prepare_fd(fdf));\n+\t\ttrace_handshake_cmd_accept(net, req, req-\u003ehr_sk, fdf-\u003efd);\n \t\tfd_publish(fdf);\n \t\treturn 0;\n \t}\ndiff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c\nindex 71af69d442f21..962ee2c4acd2f 100644\n--- a/net/kcm/kcmsock.c\n+++ b/net/kcm/kcmsock.c\n@@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket sock, unsigned int cmd, unsigned long arg)\n \t\tstruct kcm_clone info;\n \n \t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \n-\t\tinfo.fd = fd_prepare_fd(fdf);\n+\t\tinfo.fd = fdf-\u003efd;\n \t\tif (copy_to_user((void __user *)arg, \u0026info, sizeof(info)))\n \t\t\treturn -EFAULT;\n \n" }
2/1	2026/09/19 01:36	agent	patch-evaluator	5m Model: core Args: null Results: { "EnableConfigs": [ "BPF_SYSCALL", "USERFAULTFD", "NTSYNC", "AF_KCM", "XFS_FS", "NET_HANDSHAKE", "MEDIA_SUPPORT", "MEDIA_CONTROLLER", "GPIOLIB", "GPIO_CDEV", "GPIO_CDEV_V1" ], "FocusSymbols": [ "receive_fd", "scm_recv_one_fd", "bpf_iter_new_fd", "bpf_token_create", "xfs_open_by_handle", "media_request_alloc", "handshake_nl_accept_doit", "kcm_ioctl", "ntsync_obj_get_fd" ], "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.", "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 58a61ff73c4736b57ba577d0b474d08304b94c83 Author: syz-cluster <triage@syzkaller.com> Date: Sat Sep 19 01:36:27 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c index 2b54afb31529f..5c06f69c9f7f9 100644 --- a/arch/powerpc/platforms/cell/spufs/inode.c +++ b/arch/powerpc/platforms/cell/spufs/inode.c @@ -266,9 +266,9 @@ spufs_mkdir(struct inode dir, struct dentry dentry, unsigned int flags, static int spufs_context_open(const struct path path) { FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; - fd_prepare_file(fdf)->f_op = &spufs_context_fops; + if (fdf->fd < 0) + return fdf->fd; + fdf->file->f_op = &spufs_context_fops; return fd_publish(fdf); } @@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path path) * in error path of _open(). / FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; - fd_prepare_file(fdf)->f_op = &spufs_gang_fops; + if (fdf->fd < 0) + return fdf->fd; + fdf->file->f_op = &spufs_gang_fops; return fd_publish(fdf); } diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 9f3b628d57934..6526ce27ea446 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-linehandle", &linehandle_fileops, lh, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(lh); - handlereq.fd = fd_prepare_fd(fdf); + handlereq.fd = fdf->fd; if (copy_to_user(ip, &handlereq, sizeof(handlereq))) return -EFAULT; @@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-line", &line_fileops, lr, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(lr); - ulr.fd = fd_prepare_fd(fdf); + ulr.fd = fdf->fd; if (copy_to_user(ip, &ulr, sizeof(ulr))) return -EFAULT; @@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-event", &lineevent_fileops, le, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(le); - eventreq.fd = fd_prepare_fd(fdf); + eventreq.fd = fdf->fd; if (copy_to_user(ip, &eventreq, sizeof(eventreq))) return -EFAULT; diff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c index ce65b1160955e..7fa2e858bd082 100644 --- a/drivers/gpu/drm/msm/msm_perfcntr.c +++ b/drivers/gpu/drm/msm/msm_perfcntr.c @@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device dev, void data, struct drm_file f FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("[msm_perfcntrs]", &stream_fops, stream, 0)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; INIT_WORK(&stream->sel_work, sel_worker); kthread_init_work(&stream->sample_work, sample_worker); diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c index 13e77648807c2..e1387f039780b 100644 --- a/drivers/media/mc/mc-request.c +++ b/drivers/media/mc/mc-request.c @@ -316,15 +316,15 @@ int media_request_alloc(struct media_device mdev, int alloc_fd) FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC)); - if (fdf.err) { - ret = fdf.err; + if (fdf->fd < 0) { + ret = fdf->fd; goto err_free_req; } - fd_prepare_file(fdf)->private_data = req; + fdf->file->private_data = req; snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d", - atomic_inc_return(&mdev->request_id), fd_prepare_fd(fdf)); + atomic_inc_return(&mdev->request_id), fdf->fd); atomic_inc(&mdev->num_requests); dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str); diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 4a805919bb0c5..2857ae37d3c81 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj obj) { FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR)); - if (fdf.err) - return fdf.err; - obj->file = fd_prepare_file(fdf); + if (fdf->fd < 0) + return fdf->fd; + obj->file = fdf->file; return fd_publish(fdf); } diff --git a/fs/eventfd.c b/fs/eventfd.c index 9d33a02757d52..52426795752ec 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags) FD_PREPARE(fdf, flags, anon_inode_getfile_fmode("[eventfd]", &eventfd_fops, ctx, flags, FMODE_NOWAIT)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL); retain_and_null_ptr(ctx); diff --git a/fs/eventpoll.c b/fs/eventpoll.c index e0c4bf88a8383..f48b829a710f7 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags) FD_PREPARE(fdf, O_RDWR \| (flags & O_CLOEXEC), anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep, O_RDWR \| (flags & O_CLOEXEC))); - if (fdf.err) { + if (fdf->fd < 0) { ep_clear_and_put(ep); - return fdf.err; + return fdf->fd; } - ep->file = fd_prepare_file(fdf); + ep->file = fdf->file; return fd_publish(fdf); } diff --git a/fs/file.c b/fs/file.c index 628ca07dc4b17..2a01b22eb65a1 100644 --- a/fs/file.c +++ b/fs/file.c @@ -1391,17 +1391,17 @@ int receive_fd(struct file file, int __user ufd, unsigned int o_flags) return error; FD_PREPARE(fdf, o_flags, file); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; get_file(file); if (ufd) { - error = put_user(fd_prepare_fd(fdf), ufd); + error = put_user(fdf->fd, ufd); if (error) return error; } - __receive_sock(fd_prepare_file(fdf)); + __receive_sock(fdf->file); return fd_publish(fdf); } EXPORT_SYMBOL_GPL(receive_fd); diff --git a/fs/namespace.c b/fs/namespace.c index 1ecd96c918b33..0f5c00816775b 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0, dentry_open(&new_path, O_PATH, fc->cred)); - if (fdf.err) { + if (fdf->fd < 0) { dissolve_on_fput(new_path.mnt); - return fdf.err; + return fdf->fd; } /* * Attach to an apparent O_PATH fd with a note that we * need to unmount it, not just simply put it. / - fd_prepare_file(fdf)->f_mode \|= FMODE_NEED_UNMOUNT; + fdf->file->f_mode \|= FMODE_NEED_UNMOUNT; return fd_publish(fdf); } @@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user , filename, return -EINVAL; FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; if (uattr) { struct mount_kattr kattr = {}; - struct file file = fd_prepare_file(fdf); + struct file file = fdf->file; int ret; if (flags & OPEN_TREE_CLONE) diff --git a/fs/nsfs.c b/fs/nsfs.c index c3b6ae76594a8..56ea0bb9ef3a3 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -348,8 +348,8 @@ static long ns_ioctl(struct file filp, unsigned int ioctl, return ret; FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; / * If @uinfo is passed return all information about the * mount namespace as well. diff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c index 0689cade8f74c..303bcff644596 100644 --- a/fs/xfs/xfs_handle.c +++ b/fs/xfs/xfs_handle.c @@ -272,11 +272,11 @@ xfs_open_by_handle( path.mnt = mntget(parfilp->f_path.mnt); FD_PREPARE(fdf, 0, dentry_open(&path, hreq->oflags, cred)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; if (S_ISREG(inode->i_mode)) { - struct file filp = fd_prepare_file(fdf); + struct file filp = fdf->file; filp->f_flags \|= O_NOATIME; filp->f_mode \|= FMODE_NOCMTIME; diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index b1b5698cbf1b6..1fb8058b897d4 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void val) CLASS(name, var)(args...): * declare the variable @var as an instance of the named class * - * CLASS_INIT(name, var, init_expr): - * declare the variable @var as an instance of the named class with - * custom initialization expression. - * * Ex. * * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd) @@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_ class_##_name##_t var __cleanup(class_##_name##_destructor) = \ class_##_name##_constructor -#define CLASS_INIT(_name, _var, _init_expr) \ - class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr) - #define __scoped_class(_name, var, _label, args...) \ for (CLASS(_name, var)(args); ; ({ goto _label; })) \ if (0) { \ diff --git a/include/linux/file.h b/include/linux/file.h index 27484b444d315..41c3c0be10644 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -12,6 +12,7 @@ #include <linux/errno.h> #include <linux/cleanup.h> #include <linux/err.h> +#include <linux/vfsdebug.h> struct file; @@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; /* * fd_prepare: Combined fd + file allocation cleanup class. - * @err: Error code to indicate if allocation succeeded. - * @__fd: Allocated fd (may not be accessed directly) - * @__file: Allocated struct file pointer (may not be accessed directly) + * @fd: Allocated fd + * @file: Allocated struct file pointer * * Allocates an fd and a file together. On error paths, automatically cleans * up whichever resource was successfully allocated. Allows flexible file * allocation with different functions per usage. * - * Do not use directly. + * Do not declare directly, use FD_PREPARE(). / struct fd_prepare { - s32 err; - s32 __fd; / do not access directly / - struct file __file; /* do not access directly / + int fd; + struct file file; }; -/* Typedef for fd_prepare cleanup guards. / -typedef struct fd_prepare class_fd_prepare_t; - -/ - * Accessors for fd_prepare class members. - * _Generic() is used for zero-cost type safety. - / -#define fd_prepare_fd(_fdf) \ - (_Generic((_fdf), struct fd_prepare: (_fdf).__fd)) - -#define fd_prepare_file(_fdf) \ - (_Generic((_fdf), struct fd_prepare: (_fdf).__file)) - / Do not use directly. / -static inline void class_fd_prepare_destructor(const struct fd_prepare fdf) +static __always_inline void __fd_prepare_cleanup(const struct fd_prepare fdf) { - if (unlikely(fdf->__fd >= 0)) - put_unused_fd(fdf->__fd); - if (unlikely(!IS_ERR_OR_NULL(fdf->__file))) - fput(fdf->__file); + if (unlikely(fdf->fd >= 0)) { + put_unused_fd(fdf->fd); + fput(fdf->file); + } } / Do not use directly. / -static inline int class_fd_prepare_lock_err(const struct fd_prepare fdf) +static __always_inline struct fd_prepare __fd_prepare(int fd, struct file file) { - if (unlikely(fdf->err)) - return fdf->err; - if (unlikely(fdf->__fd < 0)) - return fdf->__fd; - if (unlikely(IS_ERR(fdf->__file))) - return PTR_ERR(fdf->__file); - if (unlikely(!fdf->__file)) - return -ENOMEM; - return 0; + if (fd >= 0 && IS_ERR_OR_NULL(file)) { + int err = file ? PTR_ERR(file) : -ENOMEM; + + put_unused_fd(fd); + fd = err; + file = NULL; + } + return (struct fd_prepare){ .fd = fd, .file = file }; } / - * __FD_PREPARE_INIT - Helper to initialize fd_prepare class. - * @_fd_flags: flags for get_unused_fd_flags() - * @_file_owned: expression that returns struct file * - * - * Returns a struct fd_prepare with fd, file, and err set. - * If fd allocation fails, fd will be negative and err will be set. If - * fd succeeds but file_init_expr fails, file will be ERR_PTR and err - * will be set. The err field is the single source of truth for error - * checking. - / -#define __FD_PREPARE_INIT(_fd_flags, _file_owned) \ - ({ \ - struct fd_prepare fdf = { \ - .__fd = get_unused_fd_flags((_fd_flags)), \ - }; \ - if (likely(fdf.__fd >= 0)) \ - fdf.__file = (_file_owned); \ - fdf.err = ACQUIRE_ERR(fd_prepare, &fdf); \ - fdf; \ - }) - -/ - * FD_PREPARE - Macro to declare and initialize an fd_prepare variable. + * FD_PREPARE - Declare and initialize an fd_prepare instance. * - * Declares and initializes an fd_prepare variable with automatic - * cleanup. No separate scope required - cleanup happens when variable - * goes out of scope. + * This allocates a new fd and only evaluates @_file_owned if the + * allocation succeeded. Cleanup happens when the variable goes out of + * scope and the guard releases whichever of the descriptor and the file + * was allocated. If fd_publish() was called the fd and file are + * published and cleanup becomes a nop. * - * @_fdf: name of struct fd_prepare variable to define + * @_fdf: name of the const struct fd_prepare pointer to define * @_fd_flags: flags for get_unused_fd_flags() * @_file_owned: struct file to take ownership of (can be expression) / +#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned) \ + struct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({ \ + int __fd = get_unused_fd_flags(_fd_flags); \ + __fd_prepare(__fd, __fd < 0 ? NULL : (_file_owned)); \ + }); \ + const struct fd_prepare const _fdf = &_guard + #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \ - CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned)) + __FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned) /* * fd_publish - Publish prepared fd and file to the fd table. - * @_fdf: struct fd_prepare variable + * @fdf: struct fd_prepare pointer defined by FD_PREPARE() / -#define fd_publish(_fdf) \ - ({ \ - struct fd_prepare fdp = &(_fdf); \ - VFS_WARN_ON_ONCE(fdp->err); \ - VFS_WARN_ON_ONCE(fdp->__fd < 0); \ - VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \ - fd_install(fdp->__fd, fdp->__file); \ - retain_and_null_ptr(fdp->__file); \ - take_fd(fdp->__fd); \ - }) +static __always_inline int fd_publish(const struct fd_prepare fdf) +{ + / Callers only get a const view, the guard itself is writable. / + struct fd_prepare guard = (struct fd_prepare )fdf; + + VFS_WARN_ON_ONCE(guard->fd < 0); + fd_install(guard->fd, guard->file); + return take_fd(guard->fd); +} / Do not use directly. / -#define __FD_ADD(_fdf, _fd_flags, _file_owned) \ - ({ \ - FD_PREPARE(_fdf, _fd_flags, _file_owned); \ - s32 ret = _fdf.err; \ - if (likely(!ret)) \ - ret = fd_publish(_fdf); \ - ret; \ +#define __FD_ADD(_fdf, _fd_flags, _file_owned) \ + ({ \ + FD_PREPARE(_fdf, _fd_flags, _file_owned); \ + _fdf->fd < 0 ? _fdf->fd : fd_publish(_fdf); \ }) / diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c index b318ed697998e..9f0b4d850c12f 100644 --- a/io_uring/mock_file.c +++ b/io_uring/mock_file.c @@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd cmd, unsigned int issue_flag FD_PREPARE(fdf, O_RDWR \| O_CLOEXEC, anon_inode_create_getfile("[io_uring_mock]", fops, mf, O_RDWR \| O_CLOEXEC, NULL)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(mf); - file = fd_prepare_file(fdf); + file = fdf->file; file->f_mode \|= FMODE_READ \| FMODE_CAN_READ \| FMODE_WRITE \| FMODE_CAN_WRITE \| FMODE_LSEEK; if (mc.flags & IORING_MOCK_CREATE_F_SUPPORT_NOWAIT) file->f_mode \|= FMODE_NOWAIT; - mc.out_fd = fd_prepare_fd(fdf); + mc.out_fd = fdf->fd; if (copy_to_user(uarg, &mc, uarg_size)) return -EFAULT; diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 14a5fdfa04214..5f790d12f72e1 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link link) flags = O_RDONLY \| O_CLOEXEC; FD_PREPARE(fdf, flags, anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; iter_link = container_of(link, struct bpf_iter_link, link); - err = prepare_seq_file(fd_prepare_file(fdf), iter_link); + err = prepare_seq_file(fdf->file, iter_link); if (err) return err; /* Automatic cleanup handles fput / diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c index e85a179523f02..da915a4f972b1 100644 --- a/kernel/bpf/token.c +++ b/kernel/bpf/token.c @@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr attr) FD_PREPARE(fdf, O_CLOEXEC, alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME, O_RDWR, &bpf_token_fops)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; token = kzalloc_obj(token, GFP_USER); if (!token) @@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr attr) return err; get_user_ns(token->userns); - fd_prepare_file(fdf)->private_data = no_free_ptr(token); + fdf->file->private_data = no_free_ptr(token); return fd_publish(fdf); } diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 23fb68fce000e..ea382aedfc90d 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags) anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx, O_RDONLY \| (flags & UFFD_SHARED_FCNTL_FLAGS), NULL)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; /* prevent the mm struct to be freed / mmgrab(ctx->mm); - fd_prepare_file(fdf)->f_mode \|= FMODE_NOWAIT; + fdf->file->f_mode \|= FMODE_NOWAIT; retain_and_null_ptr(ctx); return fd_publish(fdf); } diff --git a/net/core/scm.c b/net/core/scm.c index f0d44ecdb11fc..15c330784a699 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file f, int __user ufd, unsigned int flags, return notrunc ? put_user(error, ufd) : error; FD_PREPARE(fdf, flags, get_file(f)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; - error = put_user(fd_prepare_fd(fdf), ufd); + error = put_user(fdf->fd, ufd); if (error) return error; - __receive_sock(fd_prepare_file(fdf)); + __receive_sock(fdf->file); return fd_publish(fdf); } diff --git a/net/handshake/netlink.c b/net/handshake/netlink.c index 3fd4fef9bab1a..73b8314d9010c 100644 --- a/net/handshake/netlink.c +++ b/net/handshake/netlink.c @@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff skb, struct genl_info info) req = handshake_req_next(hn, class); if (req) { FD_PREPARE(fdf, O_CLOEXEC, req->hr_file); - if (fdf.err) { + if (fdf->fd < 0) { fput(req->hr_file); / drop ref from handshake_req_next() / - err = fdf.err; + err = fdf->fd; goto out_complete; } - err = req->hr_proto->hp_accept(req, info, fd_prepare_fd(fdf)); + err = req->hr_proto->hp_accept(req, info, fdf->fd); if (err) goto out_complete; / Automatic cleanup handles fput / - trace_handshake_cmd_accept(net, req, req->hr_sk, fd_prepare_fd(fdf)); + trace_handshake_cmd_accept(net, req, req->hr_sk, fdf->fd); fd_publish(fdf); return 0; } diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index 71af69d442f21..962ee2c4acd2f 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket sock, unsigned int cmd, unsigned long arg) struct kcm_clone info; FD_PREPARE(fdf, 0, kcm_clone(sock)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; - info.fd = fd_prepare_fd(fdf); + info.fd = fdf->fd; if (copy_to_user((void __user *)arg, &info, sizeof(info))) return -EFAULT;
3/2	2026/09/19 01:36	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 11715 output: 30 thoughts: 1279 Thoughts: Analyzing the `fd_prepare` Abstraction Refactor Okay, let's dive into this patch. The target architecture is amd64, so we need to keep that in mind. The commit touches quite a few subsystems, which suggests this is a relatively widespread, core change. We have `arch/powerpc/platforms/cell/spufs/inode.c`, `drivers/gpio/gpiolib-cdev.c`, `drivers/gpu/drm/msm/msm_perfcntr.c`, and so on. That means this has the potential to impact a good chunk of the kernel. The key seems to be the refactoring of the `fd_prepare` abstraction in `include/linux/file.h`. Let's compare the before and after versions. It appears they've streamlined the struct itself. Previously, there were these internal members `__fd` and `__file`, which were hidden. Now, we have direct members: `int fd` and `struct file file`. This looks cleaner and more direct. The original had a `class_fd_prepare_t` alias and a destructor `class_fd_prepare_destructor`. The destructor handled releasing the file descriptor and the file itself. Now, this seems to have been broken into two functions, an inline `__fd_prepare_cleanup` and `__fd_prepare` to deal with the `fd` and the `file`. Now, the macro `FD_PREPARE` is the point of interest. What does `__FD_PREPARE` do? It creates a temporary variable, uses a `__cleanup` attribute to call `__fd_prepare_cleanup`, and then assigns a struct to `_fdf`. Seems safe. And what's this? They've also refactored the `fd_publish` macro. This is where things get interesting. Previously, `fd_publish` used `retain_and_null_ptr(fdp->__file)`. Where the previous implementation relied on a set of `VFS_WARN_ON_ONCE` and `retain_and_null_ptr`, the current version, the caller gets a `const` view of the `_fdf`, and that `fd_publish` function uses `fd_install` and `take_fd`. I need to understand what `take_fd` actually* does. Let's dig into that `take_fd` function in `include/linux/file.h`. That's where the real magic happens, so let's see exactly what's changed there.
4/2	2026/09/19 01:36	tool	grepper	0m Args: { "Expression": "take_fd", "PathPrefix": "include/linux/file.h" } Results: { "Output": "include/linux/file.h=98=DEFINE_FREE(fput, struct file , if (!IS_ERR_OR_NULL(_T)) fput(_T))\n--\ninclude/linux/file.h-100-/\ninclude/linux/file.h:101: * take_fd() will take care to set @fd to -EBADF ensuring that\ninclude/linux/file.h-102- * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it\n--\ninclude/linux/file.h-115- * fd_install(fd, f);\ninclude/linux/file.h:116: * return take_fd(fd);\ninclude/linux/file.h-117- /\ninclude/linux/file.h:118:#define take_fd(fd) __get_and_null(fd, -EBADF)\ninclude/linux/file.h-119-\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare fdf)\n--\ninclude/linux/file.h-202-\tfd_install(guard-\u003efd, guard-\u003efile);\ninclude/linux/file.h:203:\treturn take_fd(guard-\u003efd);\ninclude/linux/file.h-204-}\n" }
5/2	2026/09/19 01:36	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13916 output: 34 thoughts: 1546 Thoughts: Analyzing Potential Kernel File Descriptor Vulnerabilities Okay, let's break this down. My initial thought process revolves around a specific pattern in the Linux kernel: the use of `FD_PREPARE` and `fd_publish` for file descriptor management, along with the associated cleanup functions, namely `__fd_prepare_cleanup`. I immediately recognize the importance of meticulously tracing the execution paths and potential error conditions within this specific design. My first observation is the `take_fd(guard->fd)` macro, which sets the file descriptor `guard->fd` to -EBADF if the FD is not valid. That's my starting point. The crucial question is: under what circumstances does the kernel not publish an FD, and what happens during the subsequent cleanup? I'm looking for race conditions and vulnerabilities, where the intended FD management might be bypassed. The code for `__fd_prepare_cleanup` is clear: it will check if `fdf->fd` is greater than or equal to zero and if so call `put_unused_fd` and `fput`. But, what if an error occurs before `fd_publish` is called? The initial FD might be valid, but then get set to a negative error code. If so, and the error happens before publish, `put_unused_fd` and `fput` will be called, as the check `fdf->fd >= 0` is still true at this stage. I immediately realize that this might lead to a double-free or use-after-free, if that FD has been released by the error handling. The interesting thing is if `_file_owned` fails. This is handled by `__fd_prepare`, but the key here is what happens if `file` is NULL or an error pointer. If it is, then `put_unused_fd(fd)` is called immediately, `fd` is set to negative, and `file` is set to NULL. My thought is, on cleanup, the cleanup function will see a negative FD, and do nothing, but the FD could have already been put back into the unused FD table. That means that the FD could potentially have been cleaned up twice. I'm thinking about whether this could be reached in amd64. I recognize that there are several core system calls that use `FD_PREPARE`. Specifically, eventfd, epoll_create, fsmount, open_tree, receive_fd, userfaultfd, and bpf_iter_new_fd are among the many syscalls and subsystems in Linux that use this. It is quite clear that any logic modifications in memory management, synchronization/locking, BPF, scheduler, core networking, VFS, or syscall handling should be carefully examined. Refactorings and code cleanups also need to be very carefully reviewed because they are frequently the sources of subtle bugs. The cleanup function `__fd_prepare_cleanup` is worth examining. The interesting part here is that `fdf->file` could be NULL or an ERR_PTR if it was prepared that way. It is important to know that if `fdf->fd >= 0`, `fdf->file` must be a valid file pointer, which I am comfortable with because of the logic. I immediately start to look for vulnerable code paths that might result in `fd_publish` not being called, especially situations after a valid FD preparation. `drivers/gpio/gpiolib-cdev.c` immediately catches my eye. If `copy_to_user` fails in the code there, the scope ends, `__fd_prepare_cleanup` is called. That means that `put_unused_fd(fdf->fd)` and `fput(fdf->file)` are called! I shift my attention to `drivers/media/mc/mc-request.c`. It's another potential location, but I notice that the code sets `fdf->file->private_data = req`. I start to wonder if there could be a case where the file is cleaned up, but the data is not. Now I'm looking at `fs/eventfd.c` and specifically `do_eventfd`. What happens if the `ida_alloc` call fails? Is there a path to a double free, or a missed cleanup? I need to dig into the eventfd code to see what that branch does, and what state it leaves the file descriptor and associated data in. I'm focusing on the exact sequence of events, and where errors can interrupt the normal `fd_publish` flow.
6/2	2026/09/19 01:37	tool	read-file	0m Args: { "File": "fs/eventfd.c", "FirstLine": 390, "LineCount": 40 } Results: { "Contents": " 390:\t\n 391:\t\tctx = kmalloc_obj(*ctx);\n 392:\t\tif (!ctx)\n 393:\t\t\treturn -ENOMEM;\n 394:\t\n 395:\t\tkref_init(\u0026ctx-\u003ekref);\n 396:\t\tinit_waitqueue_head(\u0026ctx-\u003ewqh);\n 397:\t\tctx-\u003ecount = count;\n 398:\t\tctx-\u003eflags = flags;\n 399:\t\n 400:\t\tflags \u0026= EFD_SHARED_FCNTL_FLAGS;\n 401:\t\tflags \|= O_RDWR;\n 402:\t\n 403:\t\tFD_PREPARE(fdf, flags,\n 404:\t\t\t anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n 405:\t\t\t\t\t\t flags, FMODE_NOWAIT));\n 406:\t\tif (fdf-\u003efd \u003c 0)\n 407:\t\t\treturn fdf-\u003efd;\n 408:\t\n 409:\t\tctx-\u003eid = ida_alloc(\u0026eventfd_ida, GFP_KERNEL);\n 410:\t\tretain_and_null_ptr(ctx);\n 411:\t\treturn fd_publish(fdf);\n 412:\t}\n 413:\t\n 414:\tSYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)\n 415:\t{\n 416:\t\treturn do_eventfd(count, flags);\n 417:\t}\n 418:\t\n 419:\tSYSCALL_DEFINE1(eventfd, unsigned int, count)\n 420:\t{\n 421:\t\treturn do_eventfd(count, 0);\n 422:\t}\n 423:\t\n" }
7/2	2026/09/19 01:37	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16947 output: 34 thoughts: 39 Thoughts: Okay, here's my interpretation of that thought process, assuming I'm deep in the code: Diving into `retain_and_null_ptr(ctx)` Alright, let's dissect this `retain_and_null_ptr(ctx)` call. Hold on a sec... ctx. Hmm, I need to immediately understand the context of `ctx`. Let's skip to the declaration real quick. Line numbers 380 to 395 should hold the key, I'll go check those lines. That's where I need to start to understand what's actually going on here with this call.
8/2	2026/09/19 01:37	tool	read-file	0m Args: { "File": "fs/eventfd.c", "FirstLine": 380, "LineCount": 15 } Results: { "Contents": " 380:\t{\n 381:\t\tstruct eventfd_ctx ctx __free(kfree) = NULL;\n 382:\t\n 383:\t\t/ Check the EFD_* constants for consistency. /\n 384:\t\tBUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);\n 385:\t\tBUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);\n 386:\t\tBUILD_BUG_ON(EFD_SEMAPHORE != (1 \u003c\u003c 0));\n 387:\t\n 388:\t\tif (flags \u0026 ~EFD_FLAGS_SET)\n 389:\t\t\treturn -EINVAL;\n 390:\t\n 391:\t\tctx = kmalloc_obj(ctx);\n 392:\t\tif (!ctx)\n 393:\t\t\treturn -ENOMEM;\n 394:\t\n" }
9/2	2026/09/19 01:37	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 17395 output: 35 thoughts: 38 Thoughts: Okay, let's dive into this. Examining `do_epoll_create` Right, so I need to understand the initial setup for epoll. Let's head over to `fs/eventpoll.c` and specifically focus on the `do_epoll_create` function. I want to zero in on lines 2500 through 2530. Those lines should cover the core initialization. I'll be looking for how the data structures are allocated and initialized, any security checks, and how the file descriptor is assigned. My experience tells me this is where the groundwork is laid, so this is the best place to find the kernel's first steps in setting up an epoll instance. Let's see what we're working with here!
10/2	2026/09/19 01:37	tool	read-file	0m Args: { "File": "fs/eventpoll.c", "FirstLine": 2500, "LineCount": 30 } Results: { "Contents": "2500:\t\tBUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);\n2501:\t\n2502:\t\tif (flags \u0026 ~EPOLL_CLOEXEC)\n2503:\t\t\treturn -EINVAL;\n2504:\t\t/\n2505:\t\t Create the internal data structure (\"struct eventpoll\").\n2506:\t\t /\n2507:\t\terror = ep_alloc(\u0026ep);\n2508:\t\tif (error \u003c 0)\n2509:\t\t\treturn error;\n2510:\t\t/\n2511:\t\t * Creates all the items needed to setup an eventpoll file. That is,\n2512:\t\t * a file structure and a free file descriptor.\n2513:\t\t */\n2514:\t\tFD_PREPARE(fdf, O_RDWR \| (flags \u0026 O_CLOEXEC),\n2515:\t\t\t anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n2516:\t\t\t\t\t O_RDWR \| (flags \u0026 O_CLOEXEC)));\n2517:\t\tif (fdf-\u003efd \u003c 0) {\n2518:\t\t\tep_clear_and_put(ep);\n2519:\t\t\treturn fdf-\u003efd;\n2520:\t\t}\n2521:\t\tep-\u003efile = fdf-\u003efile;\n2522:\t\treturn fd_publish(fdf);\n2523:\t}\n2524:\t\n2525:\tSYSCALL_DEFINE1(epoll_create1, int, flags)\n2526:\t{\n2527:\t\treturn do_epoll_create(flags);\n2528:\t}\n2529:\t\n" }
11/2	2026/09/19 01:37	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 18086 output: 34 thoughts: 33 Thoughts: Okay, let's dive into this. I need to understand how file descriptors are received in the kernel, so I'll zero in on `receive_fd` within `fs/file.c`. Specifically, I'm going to focus on lines 1380 through 1415. I'm expecting this section to illuminate the mechanism by which file descriptors are transferred, potentially across processes or through a socket, and how the kernel handles the reception and validation of these descriptors. I'll be looking for the crucial data structures involved – the relevant `struct file`, `struct fdtable`, perhaps some socket-related structures if inter-process communication is involved – and how the kernel ensures the integrity and security of the transferred file descriptors. I'm anticipating some intricate pointer management and reference counting to be in play here, as well as some careful checks to prevent resource leaks and potential security vulnerabilities. Time to dig in and see how the kernel engineers solved this.
12/2	2026/09/19 01:37	tool	read-file	0m Args: { "File": "fs/file.c", "FirstLine": 1380, "LineCount": 35 } Results: { "Contents": "1380:\t * This helper handles its own reference counting of the incoming\n1381:\t * struct file.\n1382:\t \n1383:\t Returns newly install fd or -ve on error.\n1384:\t /\n1385:\tint receive_fd(struct file file, int __user ufd, unsigned int o_flags)\n1386:\t{\n1387:\t\tint error;\n1388:\t\n1389:\t\terror = security_file_receive(file);\n1390:\t\tif (error)\n1391:\t\t\treturn error;\n1392:\t\n1393:\t\tFD_PREPARE(fdf, o_flags, file);\n1394:\t\tif (fdf-\u003efd \u003c 0)\n1395:\t\t\treturn fdf-\u003efd;\n1396:\t\tget_file(file);\n1397:\t\n1398:\t\tif (ufd) {\n1399:\t\t\terror = put_user(fdf-\u003efd, ufd);\n1400:\t\t\tif (error)\n1401:\t\t\t\treturn error;\n1402:\t\t}\n1403:\t\n1404:\t\t__receive_sock(fdf-\u003efile);\n1405:\t\treturn fd_publish(fdf);\n1406:\t}\n1407:\tEXPORT_SYMBOL_GPL(receive_fd);\n1408:\t\n1409:\tint receive_fd_replace(int new_fd, struct file file, unsigned int o_flags)\n1410:\t{\n1411:\t\tint error;\n1412:\t\n1413:\t\terror = security_file_receive(file);\n1414:\t\tif (error)\n" }
13/2	2026/09/19 01:37	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 18819 output: 22 thoughts: 3384 Thoughts: Analyzing File Descriptor Management in Kernel Code Okay, let's break this down. My initial focus is on the `receive_fd` function in `fs/file.c` and how it handles file descriptors (FDs). It looks like this code is going through a refactor, and I need to understand the implications of the changes. Initially, I'm concerned about the behavior when `put_user` fails in `receive_fd`. The core of the problem seems to be the lifetime management of the `struct file` pointer associated with the FD. First, I see the old `FD_PREPARE` macro used a struct member `fdf.err`. Now it appears that we have `fdf->fd < 0`, so I need to figure out how this is different now. I recall how it was initialized: `FD_PREPARE(fdf, o_flags, file);`. This macro sets up an unused FD and associates it with a `file` pointer, acquiring a reference count. The critical change is in how the cleanup is handled. The old code had `class_fd_prepare_destructor`, which would call `fput(file)` to release the reference if `put_user` failed. This makes sense: the FD gets cleaned up, and the file reference is dropped. The current approach uses `__fd_prepare_cleanup`. Now, the `fd_publish` function used to set the `__file` pointer to NULL and set `__fd` to -EBADF! This suggests that, in the event of success, the `file` pointer should be released. However, in the new `fd_publish`, there is no modification to the `guard->file`. This seems like a potential leak, but the guard now makes sure `__fd_prepare_cleanup` is run at the end of the `guard` lifetime, regardless. I notice that the new `fd_publish` no longer handles the `file` pointer. This is where I start to see a difference with the old code. Looking at the cleanup function `__fd_prepare_cleanup`, the check `fdf->fd >= 0` is now crucial. If it's false (because of `take_fd`), neither `put_unused_fd` nor `fput` is called after a successful `fd_publish`, and therefore no leak! Now I'm turning my attention to the `scm_recv_one_fd` function. The process flow is similar to `receive_fd`. I see that the order of `FD_PREPARE` and `get_file` calls is crucial because the old code ensures that `fput` drops the reference that `get_file` provides. So, in the original `receive_fd` code with the `ACQUIRE_ERR` macro, `get_file` was called and later, the refcount was properly dropped by `fput(file)` when an error occurs, or at the end of `fd_publish`. This avoids refcount leaks or underflows. I see that the new `__fd_prepare` function handles the initial error cases by either releasing the FD or setting `file` to `NULL`. The cleanup of the file pointer is now done only in the destructor when things go wrong. Then, I'm checking what happens in `net/handshake/netlink.c`, in the context of `netlink` connections. In this specific scenario, a `file` reference is acquired using `handshake_req_next`. I note the `fput` call if `fdf->fd < 0` to release the refcount acquired. Otherwise if `hp_accept` fails, the destructor does a clean-up. I need to emphasize that the most impactful change here involves how `fdf` is now a pointer (`const struct fd_prepare *const _fdf`) instead of a `struct fd_prepare` by value. Previously, `fdf.err` was used, but now `fdf->fd < 0` is the check. The key difference is how the FD is managed throughout the process. The original use of the struct member, `fdf.err`, is now replaced with pointer dereference, `fdf->fd < 0`. This subtle pointer use is critical for understanding the refcount changes. The focus is now ensuring that the file object is correctly released when the FD goes out of scope and, in particular, when an error occurs.
14/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "__FD_ADD\|FD_ADD" } Results: { "Output": "arch/powerpc/platforms/pseries/papr-hvpipe.c=485=static int papr_hvpipe_dev_create_handle(u32 srcID)\n--\narch/powerpc/platforms/pseries/papr-hvpipe.c-512-\narch/powerpc/platforms/pseries/papr-hvpipe.c:513:\tfd = FD_ADD(O_RDONLY \| O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-hvpipe.c-514-\t\t anon_inode_getfile(\"[papr-hvpipe]\", \u0026papr_hvpipe_handle_ops,\n--\narch/powerpc/platforms/pseries/papr-platform-dump.c=302=static long papr_platform_dump_create_handle(u64 dump_tag)\n--\narch/powerpc/platforms/pseries/papr-platform-dump.c-334-\narch/powerpc/platforms/pseries/papr-platform-dump.c:335:\tfd = FD_ADD(O_RDONLY \| O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-platform-dump.c-336-\t\t anon_inode_getfile_fmode(\"[papr-platform-dump]\",\n--\narch/powerpc/platforms/pseries/papr-rtas-common.c=203=long papr_rtas_setup_file_interface(struct papr_rtas_sequence seq,\n--\narch/powerpc/platforms/pseries/papr-rtas-common.c-213-\narch/powerpc/platforms/pseries/papr-rtas-common.c:214:\tfd = FD_ADD(O_RDONLY \| O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-rtas-common.c-215-\t\t anon_inode_getfile_fmode(name, fops, (void )blob, O_RDONLY,\n--\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c=695=static int a5xx_hw_init(struct msm_gpu gpu)\n--\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c-901-\tgpu_write(gpu, REG_A5XX_HLSQ_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c:902:\tgpu_write(gpu, REG_A5XX_VFD_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c-903-\tgpu_write(gpu, REG_A5XX_VPC_ADDR_MODE_CNTL, 0x1);\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c=1173=static int hw_init(struct msm_gpu gpu)\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c-1224-\t\tgpu_write(gpu, REG_A6XX_HLSQ_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c:1225:\t\tgpu_write(gpu, REG_A6XX_VFD_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c-1226-\t\tgpu_write(gpu, REG_A6XX_VPC_ADDR_MODE_CNTL, 0x1);\n--\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml=4=xsi:schemaLocation=\"https://gitlab.freedesktop.org/freedreno/ rules-fd.xsd\"\u003e\n--\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml-1529-\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml:1530:\t\u003creg32 offset=\"0x0e41\" name=\"VFD_ADDR_MODE_CNTL\" type=\"a5xx_address_mode\"/\u003e\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml-1531-\t\u003creg32 offset=\"0x0e42\" name=\"VFD_MODE_CNTL\"/\u003e \u003c!-- always 00000000? --\u003e\n--\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml=32=by a particular renderpass/blit.\n--\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml-3578-\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml:3579:\t\u003creg32 offset=\"0xa601\" name=\"VFD_ADDR_MODE_CNTL\" type=\"a5xx_address_mode\" variants=\"A6XX\"/\u003e\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml-3580-\t\u003carray offset=\"0xa610\" name=\"VFD_PERFCTR_VFD_SEL\" stride=\"1\" length=\"8\" variants=\"A6XX\"/\u003e\n--\ndrivers/hv/mshv_root_main.c=2048=mshv_ioctl_create_partition(void __user user_arg, struct device module_dev)\n--\ndrivers/hv/mshv_root_main.c-2107-\ndrivers/hv/mshv_root_main.c:2108:\tret = FD_ADD(O_CLOEXEC, anon_inode_getfile(\"mshv_partition\",\ndrivers/hv/mshv_root_main.c-2109-\t\t\t\t\t\t \u0026mshv_partition_fops,\n--\ndrivers/net/ethernet/atheros/alx/main.c=450=static void alx_init_ring_ptrs(struct alx_priv alx)\n--\ndrivers/net/ethernet/atheros/alx/main.c-471-\t\t\talx_write_mem32(hw, ALX_RRD_ADDR_LO, np-\u003erxq-\u003errd_dma);\ndrivers/net/ethernet/atheros/alx/main.c:472:\t\t\talx_write_mem32(hw, ALX_RFD_ADDR_LO, np-\u003erxq-\u003erfd_dma);\ndrivers/net/ethernet/atheros/alx/main.c-473-\t\t}\n--\ndrivers/net/ethernet/atheros/alx/reg.h-295-\ndrivers/net/ethernet/atheros/alx/reg.h:296:#define ALX_RFD_ADDR_LO\t\t\t\t\t0x1550\ndrivers/net/ethernet/atheros/alx/reg.h-297-#define ALX_RFD_RING_SZ\t\t\t\t\t0x1560\n--\ndrivers/net/ethernet/atheros/atlx/atl1.c=1451=static u32 atl1_configure(struct atl1_adapter adapter)\n--\ndrivers/net/ethernet/atheros/atlx/atl1.c-1474-\tiowrite32((u32) (adapter-\u003erfd_ring.dma \u0026 0x00000000ffffffffULL),\ndrivers/net/ethernet/atheros/atlx/atl1.c:1475:\t\thw-\u003ehw_addr + REG_DESC_RFD_ADDR_LO);\ndrivers/net/ethernet/atheros/atlx/atl1.c-1476-\tiowrite32((u32) (adapter-\u003errd_ring.dma \u0026 0x00000000ffffffffULL),\n--\ndrivers/net/ethernet/atheros/atlx/atl1.h=51=static u32 atl1_check_link(struct atl1_adapter adapter);\n--\ndrivers/net/ethernet/atheros/atlx/atl1.h-121-/ Descriptor Control registers, low 32 bits /\ndrivers/net/ethernet/atheros/atlx/atl1.h:122:#define REG_DESC_RFD_ADDR_LO\t\t\t0x1544\ndrivers/net/ethernet/atheros/atlx/atl1.h-123-#define REG_DESC_RRD_ADDR_LO\t\t\t0x1548\n--\ndrivers/net/ethernet/atheros/atlx/atlx.h-268-/ Internal SRAM Partition Register, high 32 bits /\ndrivers/net/ethernet/atheros/atlx/atlx.h:269:#define REG_SRAM_RFD_ADDR\t\t0x1500\ndrivers/net/ethernet/atheros/atlx/atlx.h-270-\n--\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h=22=enum {\n--\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h-578-#define CR_READ_TCB_ADDR\t\tCTL_REG(0x06E8)\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h:579:#define CR_READ_RFD_ADDR\t\tCTL_REG(0x06EC)\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h-580-#define CR_CWMIN_CWMAX\t\t\tCTL_REG(0x06F0)\n--\ndrivers/tty/pty.c=617=int ptm_open_peer(struct file master, struct tty_struct tty, int flags)\n--\ndrivers/tty/pty.c-621-\ndrivers/tty/pty.c:622:\treturn FD_ADD(flags, ptm_open_peer_file(master, tty, flags));\ndrivers/tty/pty.c-623-}\n--\ndrivers/vfio/group.c=303=static int vfio_group_ioctl_get_device_fd(struct vfio_group group,\n--\ndrivers/vfio/group.c-318-\ndrivers/vfio/group.c:319:\tfd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));\ndrivers/vfio/group.c-320-\tif (fd \u003c 0)\n--\nfs/anon_inodes.c=275=static int __anon_inode_getfd(const char name,\n--\nfs/anon_inodes.c-280-{\nfs/anon_inodes.c:281:\treturn FD_ADD(flags, __anon_inode_getfile(name, fops, priv, flags,\nfs/anon_inodes.c-282-\t\t\t\t\t\t context_inode, make_inode));\n--\nfs/autofs/dev-ioctl.c=232=static int autofs_dev_ioctl_open_mountpoint(const char name, dev_t devid)\n--\nfs/autofs/dev-ioctl.c-240-\nfs/autofs/dev-ioctl.c:241:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/autofs/dev-ioctl.c-242-}\n--\nfs/exec.c=1124=int begin_new_exec(struct linux_binprm * bprm)\n--\nfs/exec.c-1318-\t\tbprm-\u003eexecutable = NULL;\nfs/exec.c:1319:\t\tretval = FD_ADD(0, executable);\nfs/exec.c-1320-\t\tif (retval \u003c 0) {\n--\nfs/fhandle.c=427=static long do_handle_open(int mountdirfd, struct file_handle __user ufh,\n--\nfs/fhandle.c-436-\nfs/fhandle.c:437:\treturn FD_ADD(open_flag, file_open_handle(\u0026path, open_flag));\nfs/fhandle.c-438-}\n--\nfs/namespace.c=3248=SYSCALL_DEFINE3(open_tree, int, dfd, const char __user , filename, unsigned, flags)\nfs/namespace.c-3249-{\nfs/namespace.c:3250:\treturn FD_ADD(flags, vfs_open_tree(dfd, filename, flags));\nfs/namespace.c-3251-}\n--\nfs/namespace.c=4442=SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n--\nfs/namespace.c-4532-\tif (flags \u0026 FSMOUNT_NAMESPACE)\nfs/namespace.c:4533:\t\treturn FD_ADD((flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\nfs/namespace.c-4534-\t\t\t open_new_namespace(\u0026new_path, MOUNT_COPY_NEW));\n--\nfs/notify/fanotify/fanotify_user.c=1589=SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)\n--\nfs/notify/fanotify/fanotify_user.c-1727-\nfs/notify/fanotify/fanotify_user.c:1728:\tfd = FD_ADD(f_flags,\nfs/notify/fanotify/fanotify_user.c-1729-\t\t anon_inode_getfile_fmode(\"[fanotify]\", \u0026fanotify_fops,\n--\nfs/nsfs.c=123=int open_namespace(struct ns_common ns)\n--\nfs/nsfs.c-132-\nfs/nsfs.c:133:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/nsfs.c-134-}\n--\nfs/open.c=1408=static int do_sys_openat2(int dfd, const char __user filename,\n--\nfs/open.c-1416-\tCLASS(filename_flags, name)(filename, op.lookup_flags);\nfs/open.c:1417:\treturn FD_ADD(how-\u003eflags, do_file_open(dfd, name, \u0026op));\nfs/open.c-1418-}\n--\nfs/signalfd.c=251=static int do_signalfd4(int ufd, sigset_t mask, int flags)\n--\nfs/signalfd.c-272-\nfs/signalfd.c:273:\t\tfd = FD_ADD(flags \u0026 O_CLOEXEC,\nfs/signalfd.c-274-\t\t\t anon_inode_getfile_fmode(\n--\nfs/timerfd.c=424=SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)\n--\nfs/timerfd.c-463-\nfs/timerfd.c:464:\tret = FD_ADD(flags \u0026 TFD_SHARED_FCNTL_FLAGS,\nfs/timerfd.c-465-\t\t anon_inode_getfile_fmode(\"[timerfd]\", \u0026timerfd_fops, ctx,\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare fdf)\n--\ninclude/linux/file.h-206-/* Do not use directly. /\ninclude/linux/file.h:207:#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\ninclude/linux/file.h-208-\t({\t\t\t\t\t\t\t\\\n--\ninclude/linux/file.h-213-/\ninclude/linux/file.h:214: * FD_ADD - Allocate and install an fd and file in one step.\ninclude/linux/file.h-215- * @_fd_flags: flags for get_unused_fd_flags()\n--\ninclude/linux/file.h-219- /\ninclude/linux/file.h:220:#define FD_ADD(_fd_flags, _file_owned) \\\ninclude/linux/file.h:221:\t__FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)\ninclude/linux/file.h-222-\n--\nipc/mqueue.c=910=static int do_mq_open(const char __user u_name, int oflag, umode_t mode,\n--\nipc/mqueue.c-922-\tro = mnt_want_write(mnt);\t/* we'll drop it in any case /\nipc/mqueue.c:923:\tfd = FD_ADD(O_CLOEXEC, mqueue_file_open(name, mnt, oflag, ro, mode, attr));\nipc/mqueue.c-924-\tif (!ro)\n--\nmm/memfd.c=503=SYSCALL_DEFINE2(memfd_create,\n--\nmm/memfd.c-519-\tfd_flags = (flags \u0026 MFD_CLOEXEC) ? O_CLOEXEC : 0;\nmm/memfd.c:520:\treturn FD_ADD(fd_flags, memfd_alloc_file(name, flags));\nmm/memfd.c-521-}\n--\nmm/secretmem.c=224=SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)\n--\nmm/secretmem.c-236-\nmm/secretmem.c:237:\treturn FD_ADD(flags \u0026 O_CLOEXEC, secretmem_file_create(flags));\nmm/secretmem.c-238-}\n--\nnet/socket.c=2082=static int __sys_accept4_file(struct file file, struct sockaddr __user upeer_sockaddr,\n--\nnet/socket.c-2092-\nnet/socket.c:2093:\treturn FD_ADD(flags, do_accept(file, \u0026arg, upeer_sockaddr, upeer_addrlen, flags));\nnet/socket.c-2094-}\n--\nnet/unix/af_unix.c=3281=static int unix_open_file(struct sock sk)\n--\nnet/unix/af_unix.c-3291-\nnet/unix/af_unix.c:3292:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026unix_sk(sk)-\u003epath, O_PATH, current_cred()));\nnet/unix/af_unix.c-3293-}\n" }
15/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 27869 output: 36 thoughts: 522 Thoughts: Deep Dive into Kernel File Descriptor Allocation Okay, here we go. Look at this – `FD_ADD`! It's defined as a macro, wrapping `__FD_ADD`, which in turn leverages both `FD_PREPARE` and `fd_publish`. Seems straightforward enough on the surface, but given where this is used, it's clearly critical. This `FD_ADD` macro implementation is absolutely fundamental. It's used by the core system calls: `open()`, `openat()`, `openat2()`. Plus, it's touched in numerous other key areas: anonymous inodes, namespace operations, fanotify, signalfd, timerfd, message queues, memfd, sockets, and even pseudoterminals. This touches nearly everything to do with file descriptor allocation and management within the Linux kernel, not just files but pretty much anything treated as a file or accessed through a file descriptor. Think about it: every time we see an `openat()`, `accept()`, `memfd_create()`, `timerfd_create()`, even an `epoll_create()` or `eventfd()`, `fsmount()`, they are all, without exception, going through this revised macro implementation of `FD_PREPARE` and `FD_ADD`. That's a huge architectural change. Given this broad impact, I need to fully grok this. I'm going to start by reviewing `include/linux/file.h`, specifically lines 125 to 230, to make sure I understand all the implications and how this plays out in practice. Gotta make sure nothing is overlooked.
16/2	2026/09/19 01:38	tool	read-file	0m Args: { "File": "include/linux/file.h", "FirstLine": 125, "LineCount": 105 } Results: { "Contents": " 125:\t\n 126:\textern void flush_delayed_fput(void);\n 127:\textern void __fput_sync(struct file );\n 128:\t\n 129:\textern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;\n 130:\t\n 131:\t/\n 132:\t * fd_prepare: Combined fd + file allocation cleanup class.\n 133:\t * @fd: Allocated fd\n 134:\t * @file: Allocated struct file pointer\n 135:\t \n 136:\t Allocates an fd and a file together. On error paths, automatically cleans\n 137:\t * up whichever resource was successfully allocated. Allows flexible file\n 138:\t * allocation with different functions per usage.\n 139:\t \n 140:\t Do not declare directly, use FD_PREPARE().\n 141:\t /\n 142:\tstruct fd_prepare {\n 143:\t\tint fd;\n 144:\t\tstruct file file;\n 145:\t};\n 146:\t\n 147:\t/* Do not use directly. /\n 148:\tstatic __always_inline void __fd_prepare_cleanup(const struct fd_prepare fdf)\n 149:\t{\n 150:\t\tif (unlikely(fdf-\u003efd \u003e= 0)) {\n 151:\t\t\tput_unused_fd(fdf-\u003efd);\n 152:\t\t\tfput(fdf-\u003efile);\n 153:\t\t}\n 154:\t}\n 155:\t\n 156:\t/* Do not use directly. /\n 157:\tstatic __always_inline struct fd_prepare __fd_prepare(int fd, struct file file)\n 158:\t{\n 159:\t\tif (fd \u003e= 0 \u0026\u0026 IS_ERR_OR_NULL(file)) {\n 160:\t\t\tint err = file ? PTR_ERR(file) : -ENOMEM;\n 161:\t\n 162:\t\t\tput_unused_fd(fd);\n 163:\t\t\tfd = err;\n 164:\t\t\tfile = NULL;\n 165:\t\t}\n 166:\t\treturn (struct fd_prepare){ .fd = fd, .file = file };\n 167:\t}\n 168:\t\n 169:\t/\n 170:\t FD_PREPARE - Declare and initialize an fd_prepare instance.\n 171:\t \n 172:\t This allocates a new fd and only evaluates @_file_owned if the\n 173:\t * allocation succeeded. Cleanup happens when the variable goes out of\n 174:\t * scope and the guard releases whichever of the descriptor and the file\n 175:\t * was allocated. If fd_publish() was called the fd and file are\n 176:\t * published and cleanup becomes a nop.\n 177:\t \n 178:\t @_fdf: name of the const struct fd_prepare pointer to define\n 179:\t * @_fd_flags: flags for get_unused_fd_flags()\n 180:\t * @_file_owned: struct file to take ownership of (can be expression)\n 181:\t /\n 182:\t#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)\t\t\\\n 183:\t\tstruct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({\t\\\n 184:\t\t\tint __fd = get_unused_fd_flags(_fd_flags);\t\t\\\n 185:\t\t\t__fd_prepare(__fd, __fd \u003c 0 ? NULL : (_file_owned));\t\\\n 186:\t\t});\t\t\t\t\t\t\t\t\\\n 187:\t\tconst struct fd_prepare const _fdf = \u0026_guard\n 188:\t\n 189:\t#define FD_PREPARE(_fdf, _fd_flags, _file_owned) \\\n 190:\t\t__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)\n 191:\t\n 192:\t/\n 193:\t fd_publish - Publish prepared fd and file to the fd table.\n 194:\t * @fdf: struct fd_prepare pointer defined by FD_PREPARE()\n 195:\t /\n 196:\tstatic __always_inline int fd_publish(const struct fd_prepare fdf)\n 197:\t{\n 198:\t\t/* Callers only get a const view, the guard itself is writable. /\n 199:\t\tstruct fd_prepare guard = (struct fd_prepare )fdf;\n 200:\t\n 201:\t\tVFS_WARN_ON_ONCE(guard-\u003efd \u003c 0);\n 202:\t\tfd_install(guard-\u003efd, guard-\u003efile);\n 203:\t\treturn take_fd(guard-\u003efd);\n 204:\t}\n 205:\t\n 206:\t/ Do not use directly. /\n 207:\t#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\n 208:\t\t({\t\t\t\t\t\t\t\\\n 209:\t\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned);\t\\\n 210:\t\t\t_fdf-\u003efd \u003c 0 ? _fdf-\u003efd : fd_publish(_fdf);\t\\\n 211:\t\t})\n 212:\t\n 213:\t/\n 214:\t * FD_ADD - Allocate and install an fd and file in one step.\n 215:\t * @_fd_flags: flags for get_unused_fd_flags()\n 216:\t * @_file_owned: struct file to take ownership of\n 217:\t \n 218:\t Returns the allocated fd number, or negative error code on failure.\n 219:\t /\n 220:\t#define FD_ADD(_fd_flags, _file_owned) \\\n 221:\t\t__FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)\n 222:\t\n 223:\t#endif / __LINUX_FILE_H */\n" }
17/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30385 output: 27 thoughts: 21 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Investigating the Commit History Alright, so we're diving back into this code and, as always, context is key. Before I make any assumptions or start digging into the changes themselves, I want to nail down the why behind them. A thorough understanding starts with the original commit message. I need to understand the intent. Was it a bug fix? Feature implementation? Refactor? Knowing the rationale from the source is vital. Let's see if we can easily pull the commit log. A quick `git log` should give me the crucial context. Without that, I'm just guessing, and we both know guessing is a terrible approach, especially with critical code.
18/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "FD_PREPARE", "PathPrefix": "fs/" } Results: { "Output": "fs/eventfd.c=379=static int do_eventfd(unsigned int count, int flags)\n--\nfs/eventfd.c-402-\nfs/eventfd.c:403:\tFD_PREPARE(fdf, flags,\nfs/eventfd.c-404-\t\t anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n--\nfs/eventpoll.c=2494=static int do_epoll_create(int flags)\n--\nfs/eventpoll.c-2513-\t /\nfs/eventpoll.c:2514:\tFD_PREPARE(fdf, O_RDWR \| (flags \u0026 O_CLOEXEC),\nfs/eventpoll.c-2515-\t\t anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n--\nfs/file.c=1385=int receive_fd(struct file file, int __user ufd, unsigned int o_flags)\n--\nfs/file.c-1392-\nfs/file.c:1393:\tFD_PREPARE(fdf, o_flags, file);\nfs/file.c-1394-\tif (fdf-\u003efd \u003c 0)\n--\nfs/namespace.c=4442=SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n--\nfs/namespace.c-4544-\nfs/namespace.c:4545:\tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\nfs/namespace.c-4546-\t\t dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n--\nfs/namespace.c=5193=SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user , filename,\n--\nfs/namespace.c-5199-\nfs/namespace.c:5200:\tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\nfs/namespace.c-5201-\tif (fdf-\u003efd \u003c 0)\n--\nfs/nsfs.c=213=static long ns_ioctl(struct file *filp, unsigned int ioctl,\n--\nfs/nsfs.c-349-\nfs/nsfs.c:350:\t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/nsfs.c-351-\t\tif (fdf-\u003efd \u003c 0)\n--\nfs/xfs/xfs_handle.c=231=xfs_open_by_handle(\n--\nfs/xfs/xfs_handle.c-273-\nfs/xfs/xfs_handle.c:274:\tFD_PREPARE(fdf, 0, dentry_open(\u0026path, hreq-\u003eoflags, cred));\nfs/xfs/xfs_handle.c-275-\tif (fdf-\u003efd \u003c 0)\n" }
19/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 31394 output: 18 thoughts: 1107 Thoughts: Analyzing the Scope and Focus of this Kernel Patch Okay, let's break this down. First, I need to get a handle on the breadth of this commit. I've already determined that it's touching a wide range of core subsystems: the Virtual File System (VFS), Memory Management (MM), BPF (Berkeley Packet Filter), Networking (Net), and more. This is significant; it indicates that the changes likely have broad impact and could potentially introduce subtle, widespread issues, and it modifies reachable executable code on amd64. Therefore, setting `WorthFuzzing=true` is a no-brainer. Now, the crucial part: determining the `FocusSymbols`. The goal is to identify the most relevant functions or entry points to guide the fuzzer. I need to avoid listing common, high-frequency functions that are called almost everywhere, such as memory allocators, deallocators, or core synchronization primitives. Those would dilute the fuzzing effort. Instead, I need to pinpoint the specific feature logic or API entrypoints being altered. Looking specifically at the file.h header, the changes involve these inline functions: `__fd_prepare_cleanup`, `__fd_prepare`, and `fd_publish`. Because they are static and inline, they are inlined into every call site, and won't have individual symbols. I need to look for non-ubiquitous caller functions in the .c files. I'll start by checking the modified .c files. In `fs/eventfd.c`, I see `do_eventfd`, which is called by `__do_sys_eventfd2` and `__do_sys_eventfd`. However, that function might be ubiquitous, so let's check for other caller functions in the other files. In `fs/file.c`, I notice `receive_fd` is non-static (`EXPORT_SYMBOL_GPL(receive_fd)`). I'll need to investigate what calls `receive_fd` to see if it's a good focus.
20/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "receive_fd\\(" } Results: { "Output": "drivers/vdpa/vdpa_user/vduse_dev.c=1477=static long vduse_dev_ioctl(struct file file, unsigned int cmd,\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c-1520-\t\t}\ndrivers/vdpa/vdpa_user/vduse_dev.c:1521:\t\tret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));\ndrivers/vdpa/vdpa_user/vduse_dev.c-1522-\t\tfput(f);\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c=1785=static long vduse_dev_compat_ioctl(struct file file, unsigned int cmd,\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c-1817-\t\t}\ndrivers/vdpa/vdpa_user/vduse_dev.c:1818:\t\tret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));\ndrivers/vdpa/vdpa_user/vduse_dev.c-1819-\t\tfput(f);\n--\nfs/file.c=1345=int replace_fd(unsigned fd, struct file file, unsigned flags)\n--\nfs/file.c-1370-/\nfs/file.c:1371: receive_fd() - Install received file into file descriptor table\nfs/file.c-1372- * @file: struct file that was received from another process\n--\nfs/file.c-1384- /\nfs/file.c:1385:int receive_fd(struct file file, int __user ufd, unsigned int o_flags)\nfs/file.c-1386-{\n--\ninclude/linux/file.h=120=extern void fd_install(unsigned int fd, struct file file);\ninclude/linux/file.h-121-\ninclude/linux/file.h:122:int receive_fd(struct file file, int __user ufd, unsigned int o_flags);\ninclude/linux/file.h-123-\n--\nio_uring/openclose.c=305=int io_install_fixed_fd(struct io_kiocb req, unsigned int issue_flags)\n--\nio_uring/openclose.c-310-\tifi = io_kiocb_to_cmd(req, struct io_fixed_install);\nio_uring/openclose.c:311:\tret = receive_fd(req-\u003efile, NULL, ifi-\u003eo_flags);\nio_uring/openclose.c-312-\tif (ret \u003c 0)\n--\nkernel/pid.c=890=static int pidfd_getfd(struct pid pid, int fd)\n--\nkernel/pid.c-904-\nkernel/pid.c:905:\tret = receive_fd(file, NULL, O_CLOEXEC);\nkernel/pid.c-906-\tfput(file);\n--\nkernel/seccomp.c=1124=static void seccomp_handle_addfd(struct seccomp_kaddfd addfd, struct seccomp_knotif n)\n--\nkernel/seccomp.c-1133-\tif (!addfd-\u003esetfd)\nkernel/seccomp.c:1134:\t\tfd = receive_fd(addfd-\u003efile, NULL, addfd-\u003eflags);\nkernel/seccomp.c-1135-\telse\n" }
21/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33855 output: 34 thoughts: 136 Thoughts: Examining the File Descriptor Handling Okay, so `receive_fd` is a public function, not hidden away as static, and it's exported. That makes things immediately more interesting from a design perspective. Its direct use of `FD_PREPARE` with the `fdf`, `o_flags`, and `file` arguments, followed by `fd_publish`, suggests a specific workflow for handling file descriptors. I'm going to have to understand that sequence better. Now, let's look at `scm_recv_one_fd`. It's also non-static, exposed to the world (likely through `EXPORT_SYMBOL_GPL`). I remember that function's signature. I think it lives in `net/core/scm.c`. This suggests a potential interaction point or dependency between these two functions, or possibly that this is where the receiving side of the file descriptor transfer is handled, with the first being the sending part. I need to dig into `net/core/scm.c` to see how it works and how it might be interacting.
22/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "scm_recv_one_fd", "PathPrefix": "net/core/scm.c" } Results: { "Output": "net/core/scm.c=347=static int scm_max_fds(struct msghdr msg)\n--\nnet/core/scm.c-353-\nnet/core/scm.c:354:int scm_recv_one_fd(struct file f, int __user ufd, unsigned int flags,\nnet/core/scm.c-355-\t\t bool notrunc)\n--\nnet/core/scm.c=378=void scm_detach_fds(struct msghdr msg, struct scm_cookie *scm, bool notrunc)\n--\nnet/core/scm.c-396-\tfor (i = 0; i \u003c fdmax; i++) {\nnet/core/scm.c:397:\t\terr = scm_recv_one_fd(scm-\u003efp-\u003efp[i], cmsg_data + i, o_flags, notrunc);\nnet/core/scm.c-398-\t\tif (err \u003c 0)\n" }
23/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 34513 output: 39 thoughts: 208 Thoughts: Investigating Potential Attack Surfaces Okay, let's see, I need to start digging into this... I'm going to start by looking for exported or otherwise externally accessible functions, functions that could be entry points. The first one I'll look at is `media_request_alloc` in `drivers/media/mc/mc-request.c`. It's an exported function, `int media_request_alloc(struct media_device mdev, int alloc_fd)`, so that certainly warrants further investigation. Next, I'll move on to `bpf_iter_new_fd` in `kernel/bpf/bpf_iter.c`. It's a non-static function so it's also worth a look; `int bpf_iter_new_fd(struct bpf_link link)`. Then, I'll check `bpf_token_create` in `kernel/bpf/token.c`. `int bpf_token_create(union bpf_attr attr)` is also a non-static function, so I'll need to understand how it's being used. Finally, I'll need to check `xfs_open_by_handle` in `fs/xfs/xfs_handle.c`, specifically around line 231 of that file, as this likely is a useful function from a filesystem perspective. I need to understand the control flow and parameters of these functions to understand if there is a vulnerability there.
24/2	2026/09/19 01:38	tool	read-file	0m Args: { "File": "fs/xfs/xfs_handle.c", "FirstLine": 230, "LineCount": 20 } Results: { "Contents": " 230:\tint\n 231:\txfs_open_by_handle(\n 232:\t\tstruct file\t\tparfilp,\n 233:\t\txfs_fsop_handlereq_t\threq)\n 234:\t{\n 235:\t\tconst struct cred\tcred = current_cred();\n 236:\t\tint\t\t\tpermflag;\n 237:\t\tstruct inode\t\tinode;\n 238:\t\tstruct dentry\t\t*dentry;\n 239:\t\tfmode_t\t\t\tfmode;\n 240:\t\tstruct path\t\tpath __free(path_put) = {};\n 241:\t\n 242:\t\tif (!capable(CAP_SYS_ADMIN))\n 243:\t\t\treturn -EPERM;\n 244:\t\n 245:\t\tdentry = xfs_handlereq_to_dentry(parfilp, hreq);\n 246:\t\tif (IS_ERR(dentry))\n 247:\t\t\treturn PTR_ERR(dentry);\n 248:\t\tinode = d_inode(dentry);\n 249:\t\tpath.dentry = dentry;\n" }
25/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35394 output: 36 thoughts: 201 Thoughts: My Initial Thoughts on Function Visibility Okay, so `xfs_open_by_handle` isn't declared as `static`. That's good to know, it means it's available outside its immediate source file. Let's see... what about something in the netlink subsystem? I'll quickly check `handshake_nl_accept_doit` in `net/handshake/netlink.c`. Ah, nope, that's not static either – good, good. Now, let's look at `drivers/gpio/gpiolib-cdev.c`. I need to understand the visibility of functions like `linehandle_create`, `linereq_create`, and `lineevent_create`. Hold on a second, are those... static? Yep, they are. Okay, those are all declared as `static`. Now, the crucial question is, who calls these? Given the context, it's likely the `gpio_ioctl` function. Let's dig into `drivers/gpio/gpiolib-cdev.c` and see. I need to trace the usage to understand how this module handles device requests and interactions.
26/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "linehandle_create", "PathPrefix": "drivers/gpio/gpiolib-cdev.c" } Results: { "Output": "drivers/gpio/gpiolib-cdev.c=301=DEFINE_FREE(linehandle_free, struct linehandle_state , if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))\ndrivers/gpio/gpiolib-cdev.c-302-\ndrivers/gpio/gpiolib-cdev.c:303:static int linehandle_create(struct gpio_device gdev, void __user ip)\ndrivers/gpio/gpiolib-cdev.c-304-{\n--\ndrivers/gpio/gpiolib-cdev.c=2396=static long gpio_ioctl(struct file file, unsigned int cmd, unsigned long arg)\n--\ndrivers/gpio/gpiolib-cdev.c-2413-\tcase GPIO_GET_LINEHANDLE_IOCTL:\ndrivers/gpio/gpiolib-cdev.c:2414:\t\treturn linehandle_create(gdev, ip);\ndrivers/gpio/gpiolib-cdev.c-2415-\tcase GPIO_GET_LINEEVENT_IOCTL:\n" }
27/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 36156 output: 34 thoughts: 74 Thoughts: Okay, let's dive into this. I need to get a handle on the syscalls that have been touched within `fs/namespace.c`. Specifically, I'm interested in any modifications to `__do_sys_fsmount` and `__do_sys_open_tree_attr`. My initial thought is to zero in on the relevant code blocks. I'll need to check the lines around 4540-4560 and 5190-5220 in `fs/namespace.c` to see what has changed or been introduced. This is where the core of the action likely resides, and where I'll find the specific logic I need to analyze.
28/2	2026/09/19 01:38	tool	read-file	0m Args: { "File": "fs/namespace.c", "FirstLine": 4540, "LineCount": 25 } Results: { "Contents": "4540:\t\tns-\u003eroot = mnt;\n4541:\t\tns-\u003enr_mounts = 1;\n4542:\t\tmnt_add_to_ns(ns, mnt);\n4543:\t\tmntget(new_path.mnt);\n4544:\t\n4545:\t\tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\n4546:\t\t\t dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n4547:\t\tif (fdf-\u003efd \u003c 0) {\n4548:\t\t\tdissolve_on_fput(new_path.mnt);\n4549:\t\t\treturn fdf-\u003efd;\n4550:\t\t}\n4551:\t\n4552:\t\t/\n4553:\t\t Attach to an apparent O_PATH fd with a note that we\n4554:\t\t * need to unmount it, not just simply put it.\n4555:\t\t /\n4556:\t\tfdf-\u003efile-\u003ef_mode \|= FMODE_NEED_UNMOUNT;\n4557:\t\treturn fd_publish(fdf);\n4558:\t}\n4559:\t\n4560:\tstatic inline int vfs_move_mount(const struct path from_path,\n4561:\t\t\t\t\t const struct path *to_path,\n4562:\t\t\t\t\t enum mnt_tree_flags_t mflags)\n4563:\t{\n4564:\t\tint ret;\n" }
29/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 36820 output: 34 thoughts: 20 Thoughts: Okay, here's my summary, taking on the persona you requested: Navigating the Namespace Labyrinth: Lines 5190-5220 Alright, I'm diving into `fs/namespace.c` again. Always a tricky area, but I need to understand this specific section: lines 5190-5220. My initial thought is to zero in on what's going on here. The context is crucial. Based on my existing knowledge, I'm betting this segment deals with some aspect of how the kernel manages mount points, namespaces, or perhaps the transition between them. Probably something related to how the kernel handles the interactions between different processes’ views of the filesystem. I recall similar sections I've analyzed for previous projects – those always gave me a headache. I need to be precise, as even the smallest oversight can create huge problems in production systems. I'll read line-by-line, watching out for data structures being manipulated. Is this about cloning, unsharing, or something even more exotic? The comments, I hope, will be illuminating. I need to track data flow through any function calls, pay attention to the return values, and what kind of checks are in place. Then, I need to compare this section to similar logic within the module so I can know what this does within the broader context of the system. I also need to make sure this logic is secure. My immediate priority is to understand the why as much as the how. Then, I'll need to link this back to the bigger picture to ensure it all makes sense in the greater architecture.
30/2	2026/09/19 01:38	tool	read-file	0m Args: { "File": "fs/namespace.c", "FirstLine": 5190, "LineCount": 30 } Results: { "Contents": "5190:\t\treturn err;\n5191:\t}\n5192:\t\n5193:\tSYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user , filename,\n5194:\t\t\tunsigned, flags, struct mount_attr __user , uattr,\n5195:\t\t\tsize_t, usize)\n5196:\t{\n5197:\t\tif (!uattr \u0026\u0026 usize)\n5198:\t\t\treturn -EINVAL;\n5199:\t\n5200:\t\tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\n5201:\t\tif (fdf-\u003efd \u003c 0)\n5202:\t\t\treturn fdf-\u003efd;\n5203:\t\n5204:\t\tif (uattr) {\n5205:\t\t\tstruct mount_kattr kattr = {};\n5206:\t\t\tstruct file *file = fdf-\u003efile;\n5207:\t\t\tint ret;\n5208:\t\n5209:\t\t\tif (flags \u0026 OPEN_TREE_CLONE)\n5210:\t\t\t\tkattr.kflags = MOUNT_KATTR_IDMAP_REPLACE;\n5211:\t\t\tif (flags \u0026 AT_RECURSIVE)\n5212:\t\t\t\tkattr.kflags \|= MOUNT_KATTR_RECURSE;\n5213:\t\n5214:\t\t\tret = wants_mount_setattr(uattr, usize, \u0026kattr);\n5215:\t\t\tif (ret \u003e 0) {\n5216:\t\t\t\tret = do_mount_setattr(\u0026file-\u003ef_path, \u0026kattr);\n5217:\t\t\t\tfinish_mount_kattr(\u0026kattr);\n5218:\t\t\t}\n5219:\t\t\tif (ret)\n" }
31/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 37685 output: 31 thoughts: 41 Thoughts: Here's my take on the thought process, as requested: Diving into `io_uring/mock_file.c` Okay, time to get my hands dirty. I'm going to start by examining `io_uring/mock_file.c`. My immediate focus is the `io_create_mock_file` function. I need to understand its definition and, crucially, how it's actually invoked within the broader context of this `io_uring` implementation. That will give me insights into its purpose and role within the overall system.
32/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "io_create_mock_file", "PathPrefix": "io_uring/" } Results: { "Output": "io_uring/mock_file.c=197=static const struct file_operations io_mock_poll_fops = {\n--\nio_uring/mock_file.c-209-\nio_uring/mock_file.c:210:static int io_create_mock_file(struct io_uring_cmd cmd, unsigned int issue_flags)\nio_uring/mock_file.c-211-{\n--\nio_uring/mock_file.c=304=static int iou_mock_mgr_cmd(struct io_uring_cmd cmd, unsigned int issue_flags)\n--\nio_uring/mock_file.c-312-\tcase IORING_MOCK_MGR_CMD_CREATE:\nio_uring/mock_file.c:313:\t\treturn io_create_mock_file(cmd, issue_flags);\nio_uring/mock_file.c-314-\t}\n" }
33/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 38116 output: 36 thoughts: 35 Thoughts: Okay, let's dive in. Diving into `ntsync.c` Alright, time to get to it. I'm going to start by taking a look at `ntsync.c`. I need to figure out how this is implemented. Specifically, I'm interested in understanding the function `ntsync_obj_get_fd`. Let's navigate to the relevant directory, which should be `drivers/misc/ntsync.c`. That should give me a solid starting point for my analysis. Let's see what we can uncover.
34/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "ntsync_obj_get_fd", "PathPrefix": "drivers/misc/ntsync.c" } Results: { "Output": "drivers/misc/ntsync.c=704=static struct ntsync_obj ntsync_alloc_obj(struct ntsync_device dev,\n--\ndrivers/misc/ntsync.c-722-\ndrivers/misc/ntsync.c:723:static int ntsync_obj_get_fd(struct ntsync_obj obj)\ndrivers/misc/ntsync.c-724-{\n--\ndrivers/misc/ntsync.c=733=static int ntsync_create_sem(struct ntsync_device dev, void __user argp)\n--\ndrivers/misc/ntsync.c-749-\tsem-\u003eu.sem.max = args.max;\ndrivers/misc/ntsync.c:750:\tfd = ntsync_obj_get_fd(sem);\ndrivers/misc/ntsync.c-751-\tif (fd \u003c 0)\n--\ndrivers/misc/ntsync.c=757=static int ntsync_create_mutex(struct ntsync_device dev, void __user argp)\n--\ndrivers/misc/ntsync.c-773-\tmutex-\u003eu.mutex.owner = args.owner;\ndrivers/misc/ntsync.c:774:\tfd = ntsync_obj_get_fd(mutex);\ndrivers/misc/ntsync.c-775-\tif (fd \u003c 0)\n--\ndrivers/misc/ntsync.c=781=static int ntsync_create_event(struct ntsync_device dev, void __user *argp)\n--\ndrivers/misc/ntsync.c-794-\tevent-\u003eu.event.signaled = args.signaled;\ndrivers/misc/ntsync.c:795:\tfd = ntsync_obj_get_fd(event);\ndrivers/misc/ntsync.c-796-\tif (fd \u003c 0)\n" }
35/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 38790 output: 32 thoughts: 38 Thoughts: Here's my take on those thoughts: Considering `userfaultfd` Implementation Okay, so I'm thinking about `userfaultfd`. Specifically, I need to understand its core implementation. Where's the entry point? Right, it's `new_userfaultfd` in `mm/userfaultfd.c`. That function is probably where the magic starts. Time to dive into that file and see how this thing is actually put together. I need to refresh my memory on the data structures and control flow within this part of the memory management subsystem.
36/2	2026/09/19 01:38	tool	grepper	0m Args: { "Expression": "new_userfaultfd", "PathPrefix": "mm/userfaultfd.c" } Results: { "Output": "mm/userfaultfd.c=4773=static void init_once_userfaultfd_ctx(void mem)\n--\nmm/userfaultfd.c-4783-\nmm/userfaultfd.c:4784:static int new_userfaultfd(int flags)\nmm/userfaultfd.c-4785-{\n--\nmm/userfaultfd.c=4839=SYSCALL_DEFINE1(userfaultfd, int, flags)\n--\nmm/userfaultfd.c-4843-\nmm/userfaultfd.c:4844:\treturn new_userfaultfd(flags);\nmm/userfaultfd.c-4845-}\n--\nmm/userfaultfd.c=4847=static long userfaultfd_dev_ioctl(struct file file, unsigned int cmd, unsigned long flags)\n--\nmm/userfaultfd.c-4851-\nmm/userfaultfd.c:4852:\treturn new_userfaultfd(flags);\nmm/userfaultfd.c-4853-}\n" }
37/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39255 output: 39 thoughts: 41 Thoughts: Here's my summary, as if I were thinking these thoughts: Analyzing the KCM IOCTL Implementation Okay, time to dive into this `kcm_ioctl` situation. My first move is to go straight to the source. Specifically, I need to zero in on `net/kcm/kcmsock.c`. I'm interested in the `kcm_ioctl` function itself, so I'll be looking at lines 1570 through 1600. That section should give me the core logic for how the IOCTL commands are handled within the KCM framework. I'm hoping to quickly identify the specific IOCTLs supported and understand the corresponding actions. My goal here is to establish the context for this specific area and identify any potential problem points.
38/2	2026/09/19 01:38	tool	read-file	0m Args: { "File": "net/kcm/kcmsock.c", "FirstLine": 1570, "LineCount": 35 } Results: { "Contents": "1570:\t\t\tstruct kcm_unattach info;\n1571:\t\n1572:\t\t\tif (copy_from_user(\u0026info, (void __user )arg, sizeof(info)))\n1573:\t\t\t\treturn -EFAULT;\n1574:\t\n1575:\t\t\terr = kcm_unattach_ioctl(sock, \u0026info);\n1576:\t\n1577:\t\t\tbreak;\n1578:\t\t}\n1579:\t\tcase SIOCKCMCLONE: {\n1580:\t\t\tstruct kcm_clone info;\n1581:\t\n1582:\t\t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n1583:\t\t\tif (fdf-\u003efd \u003c 0)\n1584:\t\t\t\treturn fdf-\u003efd;\n1585:\t\n1586:\t\t\tinfo.fd = fdf-\u003efd;\n1587:\t\t\tif (copy_to_user((void __user )arg, \u0026info, sizeof(info)))\n1588:\t\t\t\treturn -EFAULT;\n1589:\t\n1590:\t\t\tfd_publish(fdf);\n1591:\t\t\terr = 0;\n1592:\t\t\tbreak;\n1593:\t\t}\n1594:\t\tdefault:\n1595:\t\t\terr = -ENOIOCTLCMD;\n1596:\t\t\tbreak;\n1597:\t\t}\n1598:\t\n1599:\t\treturn err;\n1600:\t}\n1601:\t\n1602:\tstatic void release_mux(struct kcm_mux mux)\n1603:\t{\n1604:\t\tstruct kcm_net knet = mux-\u003eknet;\n" }
39/2	2026/09/19 01:38	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39958 output: 34 thoughts: 197 Thoughts: My Analysis of the KCM and Namespace IOCTL Handlers Okay, so I'm looking at `kcm_ioctl`. Right off the bat, I see this is the entry point for handling `ioctl` calls specifically for KCM sockets. The key thing here is the `kcm_clone(sock)` function. We're cloning the socket, and that's being passed to `FD_PREPARE`. `FD_PREPARE` is then going to set up a file descriptor, and if that operation fails, we're returning the negative error code directly. We assign the file descriptor we got back from `FD_PREPARE` to the `info.fd` variable. This will be the fd we pass back to userspace, it's pretty standard so far. Now, this `copy_to_user` call is important. We're copying that `info` struct, which contains the new file descriptor, back to the user-space buffer pointed to by `arg`. If that `copy_to_user` fails with `-EFAULT`, the scope will exit. That means the resources allocated for the file descriptor are cleaned up. We don't have to worry about a resource leak in that case. The cleanup must be handled implicitly because the `fdf` structure is declared locally. Alright, now I'll switch gears and shift my focus to `ns_ioctl` within `fs/nsfs.c`. I'll need to go to lines 340-370 to properly see what's going on there. I'm sure there's something interesting there, related to namespace management!
40/2	2026/09/19 01:39	tool	read-file	0m Args: { "File": "fs/nsfs.c", "FirstLine": 340, "LineCount": 35 } Results: { "Contents": " 340:\t\t\tmnt_ns = get_sequential_mnt_ns(to_mnt_ns(ns), previous);\n 341:\t\t\tif (IS_ERR(mnt_ns))\n 342:\t\t\t\treturn PTR_ERR(mnt_ns);\n 343:\t\n 344:\t\t\tns = to_ns_common(mnt_ns);\n 345:\t\t\t/* Transfer ownership of @mnt_ns reference to @path. /\n 346:\t\t\tret = path_from_stashed(\u0026ns-\u003estashed, nsfs_mnt, ns, \u0026path);\n 347:\t\t\tif (ret)\n 348:\t\t\t\treturn ret;\n 349:\t\n 350:\t\t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\n 351:\t\t\tif (fdf-\u003efd \u003c 0)\n 352:\t\t\t\treturn fdf-\u003efd;\n 353:\t\t\t/\n 354:\t\t\t * If @uinfo is passed return all information about the\n 355:\t\t\t * mount namespace as well.\n 356:\t\t\t /\n 357:\t\t\tret = copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, \u0026kinfo);\n 358:\t\t\tif (ret)\n 359:\t\t\t\treturn ret;\n 360:\t\t\tret = fd_publish(fdf);\n 361:\t\t\tbreak;\n 362:\t\t}\n 363:\t\tdefault:\n 364:\t\t\tret = -ENOTTY;\n 365:\t\t}\n 366:\t\n 367:\t\treturn ret;\n 368:\t}\n 369:\t\n 370:\tint ns_get_name(char buf, size_t size, struct task_struct task,\n 371:\t\t\t\tconst struct proc_ns_operations ns_ops)\n 372:\t{\n 373:\t\tstruct ns_common *ns;\n 374:\t\tint res = -ENOENT;\n" }
41/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41075 output: 29 thoughts: 344 Thoughts: Analyzing `ns_ioctl` and Relevant Kernel Configurations Okay, let's break this down. I'm looking at `fs/nsfs.c: ns_ioctl`, specifically the `FD_PREPARE` usage with `O_CLOEXEC` and the subsequent error handling. The function calls `dentry_open`, and then checks the file descriptor `fdf->fd`. I see the `copy_ns_info_to_user` function, which makes sense for namespace information transfer. Finally, `fd_publish` is called. Now, I need to check the relevant Kconfig options to understand the dependencies and build configurations. Let's make sure I understand the context for these features. I need to confirm if these configurations are enabled: * `userfaultfd`: USERFAULTFD * `eventpoll`: EPOLL * `eventfd`: EVENTFD * `fs/file.c`: This is core VFS; it's always compiled. That's good. * `bpf_iter_new_fd`: BPF\_SYSCALL * `bpf_token_create`: BPF\_SYSCALL * `kcm`: KCM * `ntsync`: NTSYNC * `gpiolib-cdev`: GPIOLIB (and GPIO\_CDEV) * `media_request_alloc`: This requires MEDIA\_SUPPORT and MEDIA\_CONTROLLER. * `open_tree_attr` / `fsmount`: Part of core VFS, so should be built-in. * `receive_fd` / `scm_recv_one_fd`: Core VFS/NET, so likely built-in. I'll use grepper to search the Kconfig files for these features to confirm the build configuration. That should give me the full picture.
42/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "config NTSYNC", "PathPrefix": "drivers/misc/" } Results: { "Output": "drivers/misc/Kconfig=441=config OPEN_DICE\n--\ndrivers/misc/Kconfig-453-\ndrivers/misc/Kconfig:454:config NTSYNC\ndrivers/misc/Kconfig-455-\ttristate \"NT synchronization primitive emulation\"\n" }
43/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41936 output: 29 thoughts: 27 Thoughts: Investigating the `io_uring/mock_file.c` Implementation Okay, so I need to understand the configuration that enables `mock_file.c` within the `io_uring` framework. I'm going to start by going straight into the code. Time to dig into `io_uring/mock_file.c` and figure out the conditionals. The goal is to identify what settings or flags must be set for this module to be active. I'm looking for the defining factors here.
44/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "mock_file\\.o", "PathPrefix": "io_uring/" } Results: { "Output": "io_uring/Makefile=25=obj-$(CONFIG_PROC_FS) += fdinfo.o\nio_uring/Makefile:26:obj-$(CONFIG_IO_URING_MOCK_FILE) += mock_file.o\nio_uring/Makefile-27-obj-$(CONFIG_IO_URING_BPF) += bpf_filter.o\n" }
45/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42196 output: 33 thoughts: 23 Thoughts: Here's my take on those thoughts, tailored for an expert audience: IO_URING_MOCK_FILE Hunt Okay, so `CONFIG_IO_URING_MOCK_FILE`... that rings a bell. I need to quickly figure out where this macro is actually defined in the kernel source. I'm assuming it's part of the iouring subsystem, given the naming convention, but let's not make assumptions. Time to fire up the grep, find, or whatever tool is quickest to locate the definition. Understanding its scope and purpose is critical before I dive into any code that uses it. Is it a build option? A conditional compilation flag? Or something more internal to a specific part of the mock file support? Knowing its exact definition will dictate my next step, whether I'm debugging, configuring, or trying to understand a particular feature. Gotta see the implementation first.
46/2	2026/09/19 01:39	tool	grepper	0m Error: no matches Args: { "Expression": "config IO_URING_MOCK_FILE", "PathPrefix": "io_uring/" } Results: { "error": "no matches" }
47/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42462 output: 22 thoughts: 21 Thoughts: Okay, here's my summarized thought process, presented as if I were thinking it: Digging into IO_URING_MOCK_FILE Configuration Alright, time to get to work. I need to understand how `IO_URING_MOCK_FILE` is configured within this kernel tree. My immediate instinct is to leverage `grep`. It's the most efficient way to quickly search through the Kconfig files, which are, of course, where these build-time options are defined. So, I need to use `grep` across the entire source tree, targeting all the relevant Kconfig files. This should give me the configuration context I need – where it's defined, any dependencies, any default values, and so on. This should give me the information necessary to know about this option.
48/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "IO_URING_MOCK_FILE" } Results: { "Output": "include/uapi/linux/io_uring/mock_file.h:1:#ifndef LINUX_IO_URING_MOCK_FILE_H\ninclude/uapi/linux/io_uring/mock_file.h:2:#define LINUX_IO_URING_MOCK_FILE_H\ninclude/uapi/linux/io_uring/mock_file.h-3-\n--\ninit/Kconfig=1969=config GCOV_PROFILE_URING\n--\ninit/Kconfig-1981-\ninit/Kconfig:1982:config IO_URING_MOCK_FILE\ninit/Kconfig-1983-\ttristate \"Enable io_uring mock files (Experimental)\" if EXPERT\n--\nio_uring/Makefile=25=obj-$(CONFIG_PROC_FS) += fdinfo.o\nio_uring/Makefile:26:obj-$(CONFIG_IO_URING_MOCK_FILE) += mock_file.o\nio_uring/Makefile-27-obj-$(CONFIG_IO_URING_BPF) += bpf_filter.o\n" }
49/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42940 output: 33 thoughts: 31 Thoughts: Here's my take: Investigating IO_URING_MOCK_FILE Dependencies in the Kernel Configuration Okay, so I need to quickly figure out the dependencies for `IO_URING_MOCK_FILE`. My instinct is to head straight to `init/Kconfig` – that's where the heart of kernel configuration lives. I'm pretty sure it'll be around line 1982, maybe a few lines above or below, but that's a good starting point to locate the relevant menu entry. I need to understand what other options are required or might influence the visibility and selection of `IO_URING_MOCK_FILE`. Is it contingent on a specific architecture? Does it require some broader IO_URING configuration to be enabled first? I have to consider the potential for dependencies. I want a clear picture of its integration. I'll get the details on its relationships and any conditional logic tied to that configuration.
50/2	2026/09/19 01:39	tool	read-file	0m Args: { "File": "init/Kconfig", "FirstLine": 1980, "LineCount": 15 } Results: { "Contents": "1980:\t\t specific test purposes.\n1981:\t\n1982:\tconfig IO_URING_MOCK_FILE\n1983:\t\ttristate \"Enable io_uring mock files (Experimental)\" if EXPERT\n1984:\t\tdefault n\n1985:\t\tdepends on IO_URING\n1986:\t\thelp\n1987:\t\t Enable mock files for io_uring subsystem testing. The ABI might\n1988:\t\t still change, so it's still experimental and should only be enabled\n1989:\t\t for specific test purposes.\n1990:\t\n1991:\t\t If unsure, say N.\n1992:\t\n1993:\tconfig ADVISE_SYSCALLS\n1994:\t\tbool \"Enable madvise/fadvise syscalls\" if EXPERT\n" }
51/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 43424 output: 29 thoughts: 19 Thoughts: Here's my thought process, as it is: Checking `GPIO_CDEV` in `drivers/gpio/Kconfig` Okay, time to get started. My first step is to quickly confirm the presence and nature of `GPIO_CDEV`. I need to ensure it's defined within the core GPIO driver configuration. I'm going to navigate directly to `drivers/gpio/Kconfig` and verify its presence there. Knowing this Kconfig file inside and out, I already have a mental map of where things are likely located. I expect to find a definition, probably with associated help text. I want to understand if it's dependent on any other configurations, and the general purpose of this GPIO character device that I am configuring. Essentially, I'm checking the Kconfig to understand the "what" and "why" behind `GPIO_CDEV` before I dig deeper into its implementation.
52/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "config GPIO_CDEV", "PathPrefix": "drivers/gpio/" } Results: { "Output": "drivers/gpio/Kconfig=75=config GPIO_SYSFS_LEGACY\n--\ndrivers/gpio/Kconfig-82-\ndrivers/gpio/Kconfig:83:config GPIO_CDEV\ndrivers/gpio/Kconfig-84-\tbool \"Character device (/dev/gpiochipN) support\" if EXPERT\n--\ndrivers/gpio/Kconfig-95-\ndrivers/gpio/Kconfig:96:config GPIO_CDEV_V1\ndrivers/gpio/Kconfig-97-\tbool \"Support GPIO ABI Version 1\"\n" }
53/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 43804 output: 25 thoughts: 60 Thoughts: Here's my thought process, as it stands: Reviewing GPIO Device Driver Implementation Details Okay, so I'm diving into the GPIO driver code again. First, I need to make sure I'm fully up to speed with how the different versions are handled. Let's start by comparing `GPIO_CDEV_V1` and the current `GPIO_CDEV`. I know those are the key interfaces, and the versioning is important for compatibility. I recall `linehandle_create` and `lineevent_create` are specific to the `GPIO_CDEV_V1` implementation, so I'll need to double-check their interaction points within that version. This is critical for assessing how the old and new methods are handled. Next, I'll shift gears and check the `net/handshake/Kconfig` file. I need to see how the GPIO driver is being configured relative to the net handshake protocols. This could give insight into timing dependency and interoperability.
54/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "HANDSHAKE", "PathPrefix": "net/" } Results: { "Output": "\nFull output is too long, showing 500 out of 508 lines.\nUse more precise expression if possible.\n\nnet/Kconfig=92=source \"net/xdp/Kconfig\"\nnet/Kconfig-93-\nnet/Kconfig:94:config NET_HANDSHAKE\nnet/Kconfig-95-\tbool\n--\nnet/Kconfig-98-\nnet/Kconfig:99:config NET_HANDSHAKE_KUNIT_TEST\nnet/Kconfig-100-\ttristate \"KUnit tests for the handshake upcall mechanism\" if !KUNIT_ALL_TESTS\n--\nnet/Makefile=75=obj-$(CONFIG_MCTP)\t\t+= mctp/\nnet/Makefile:76:obj-$(CONFIG_NET_HANDSHAKE)\t+= handshake/\nnet/Makefile-77-obj-$(CONFIG_NET_SHAPER)\t+= shaper/\n--\nnet/bluetooth/hidp/core.c=243=static int hidp_get_raw_report(struct hid_device hid,\n--\nnet/bluetooth/hidp/core.c-312-\t} else {\nnet/bluetooth/hidp/core.c:313:\t\t/ Device returned a HANDSHAKE, indicating protocol error. /\nnet/bluetooth/hidp/core.c-314-\t\tlen = -EIO;\n--\nnet/bluetooth/hidp/core.c=459=static void hidp_process_handshake(struct hidp_session session,\n--\nnet/bluetooth/hidp/core.c-492-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:493:\t\t\tHIDP_TRANS_HANDSHAKE \| HIDP_HSHK_ERR_INVALID_PARAMETER, NULL, 0);\nnet/bluetooth/hidp/core.c-494-\t\tbreak;\n--\nnet/bluetooth/hidp/core.c=517=static int hidp_process_data(struct hidp_session session, struct sk_buff skb,\n--\nnet/bluetooth/hidp/core.c-541-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:542:\t\t\tHIDP_TRANS_HANDSHAKE \| HIDP_HSHK_ERR_INVALID_PARAMETER, NULL, 0);\nnet/bluetooth/hidp/core.c-543-\t}\n--\nnet/bluetooth/hidp/core.c=561=static void hidp_recv_ctrl_frame(struct hidp_session session,\n--\nnet/bluetooth/hidp/core.c-577-\tswitch (type) {\nnet/bluetooth/hidp/core.c:578:\tcase HIDP_TRANS_HANDSHAKE:\nnet/bluetooth/hidp/core.c-579-\t\thidp_process_handshake(session, param);\n--\nnet/bluetooth/hidp/core.c-591-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:592:\t\t\tHIDP_TRANS_HANDSHAKE \| HIDP_HSHK_ERR_UNSUPPORTED_REQUEST, NULL, 0);\nnet/bluetooth/hidp/core.c-593-\t\tbreak;\n--\nnet/bluetooth/hidp/hidp.h-33-/ HIDP transaction types /\nnet/bluetooth/hidp/hidp.h:34:#define HIDP_TRANS_HANDSHAKE\t\t\t0x00\nnet/bluetooth/hidp/hidp.h-35-#define HIDP_TRANS_HID_CONTROL\t\t\t0x10\n--\nnet/handshake/.kunitconfig=9=CONFIG_SUNRPC=y\nnet/handshake/.kunitconfig:10:CONFIG_NET_HANDSHAKE=y\nnet/handshake/.kunitconfig:11:CONFIG_NET_HANDSHAKE_KUNIT_TEST=y\n--\nnet/handshake/Makefile-2-#\nnet/handshake/Makefile:3:# Makefile for the Generic HANDSHAKE service\nnet/handshake/Makefile-4-#\n--\nnet/handshake/Makefile=11=handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o\nnet/handshake/Makefile-12-\nnet/handshake/Makefile:13:obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o\n--\nnet/handshake/genl.c-14-\nnet/handshake/genl.c:15:/ HANDSHAKE_CMD_ACCEPT - do /\nnet/handshake/genl.c:16:static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HANDLER_CLASS + 1] = {\nnet/handshake/genl.c:17:\t[HANDSHAKE_A_ACCEPT_HANDLER_CLASS] = NLA_POLICY_MAX(NLA_U32, 2),\nnet/handshake/genl.c-18-};\nnet/handshake/genl.c-19-\nnet/handshake/genl.c:20:/ HANDSHAKE_CMD_DONE - do /\nnet/handshake/genl.c:21:static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {\nnet/handshake/genl.c:22:\t[HANDSHAKE_A_DONE_STATUS] = NLA_POLICY_MAX(NLA_U32, MAX_ERRNO),\nnet/handshake/genl.c:23:\t[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },\nnet/handshake/genl.c:24:\t[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },\nnet/handshake/genl.c-25-};\n--\nnet/handshake/genl.c=28=static const struct genl_split_ops handshake_nl_ops[] = {\nnet/handshake/genl.c-29-\t{\nnet/handshake/genl.c:30:\t\t.cmd\t\t= HANDSHAKE_CMD_ACCEPT,\nnet/handshake/genl.c-31-\t\t.doit\t\t= handshake_nl_accept_doit,\nnet/handshake/genl.c-32-\t\t.policy\t\t= handshake_accept_nl_policy,\nnet/handshake/genl.c:33:\t\t.maxattr\t= HANDSHAKE_A_ACCEPT_HANDLER_CLASS,\nnet/handshake/genl.c-34-\t\t.flags\t\t= GENL_ADMIN_PERM \| GENL_CMD_CAP_DO,\n--\nnet/handshake/genl.c-36-\t{\nnet/handshake/genl.c:37:\t\t.cmd\t\t= HANDSHAKE_CMD_DONE,\nnet/handshake/genl.c-38-\t\t.doit\t\t= handshake_nl_done_doit,\nnet/handshake/genl.c-39-\t\t.policy\t\t= handshake_done_nl_policy,\nnet/handshake/genl.c:40:\t\t.maxattr\t= HANDSHAKE_A_DONE_REMOTE_AUTH,\nnet/handshake/genl.c-41-\t\t.flags\t\t= GENL_ADMIN_PERM \| GENL_CMD_CAP_DO,\n--\nnet/handshake/genl.c=45=static const struct genl_multicast_group handshake_nl_mcgrps[] = {\nnet/handshake/genl.c:46:\t[HANDSHAKE_NLGRP_NONE] = { \"none\", },\nnet/handshake/genl.c:47:\t[HANDSHAKE_NLGRP_TLSHD] = { \"tlshd\", },\nnet/handshake/genl.c-48-};\n--\nnet/handshake/genl.c=50=struct genl_family handshake_nl_family __ro_after_init = {\nnet/handshake/genl.c:51:\t.name\t\t= HANDSHAKE_FAMILY_NAME,\nnet/handshake/genl.c:52:\t.version\t= HANDSHAKE_FAMILY_VERSION,\nnet/handshake/genl.c-53-\t.netnsok\t= true,\n--\nnet/handshake/genl.h-6-\nnet/handshake/genl.h:7:#ifndef _LINUX_HANDSHAKE_GEN_H\nnet/handshake/genl.h:8:#define _LINUX_HANDSHAKE_GEN_H\nnet/handshake/genl.h-9-\n--\nnet/handshake/genl.h=19=enum {\nnet/handshake/genl.h:20:\tHANDSHAKE_NLGRP_NONE,\nnet/handshake/genl.h:21:\tHANDSHAKE_NLGRP_TLSHD,\nnet/handshake/genl.h-22-};\n--\nnet/handshake/genl.h=24=extern struct genl_family handshake_nl_family;\nnet/handshake/genl.h-25-\nnet/handshake/genl.h:26:#endif / _LINUX_HANDSHAKE_GEN_H /\n--\nnet/handshake/handshake-test.c=40=static struct handshake_proto handshake_req_alloc_proto_2 = {\nnet/handshake/handshake-test.c:41:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_NONE,\nnet/handshake/handshake-test.c-42-};\n--\nnet/handshake/handshake-test.c=44=static struct handshake_proto handshake_req_alloc_proto_3 = {\nnet/handshake/handshake-test.c:45:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_MAX,\nnet/handshake/handshake-test.c-46-};\n--\nnet/handshake/handshake-test.c=48=static struct handshake_proto handshake_req_alloc_proto_4 = {\nnet/handshake/handshake-test.c:49:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-50-};\n--\nnet/handshake/handshake-test.c=52=static struct handshake_proto handshake_req_alloc_proto_5 = {\nnet/handshake/handshake-test.c:53:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-54-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake-test.c=57=static struct handshake_proto handshake_req_alloc_proto_6 = {\nnet/handshake/handshake-test.c:58:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-59-\t.hp_privsize\t\t= UINT_MAX,\n--\nnet/handshake/handshake-test.c=64=static struct handshake_proto handshake_req_alloc_proto_good = {\nnet/handshake/handshake-test.c:65:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-66-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake-test.c=362=static void handshake_req_cancel_test2(struct kunit test)\n--\nnet/handshake/handshake-test.c-394-\t/* Pretend to accept this request /\nnet/handshake/handshake-test.c:395:\tnext = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);\nnet/handshake/handshake-test.c-396-\tKUNIT_ASSERT_PTR_EQ(test, req, next);\n--\nnet/handshake/handshake-test.c=412=static void handshake_req_cancel_test3(struct kunit test)\n--\nnet/handshake/handshake-test.c-444-\t/* Pretend to accept this request /\nnet/handshake/handshake-test.c:445:\tnext = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);\nnet/handshake/handshake-test.c-446-\tKUNIT_ASSERT_PTR_EQ(test, req, next);\n--\nnet/handshake/handshake-test.c=473=static struct handshake_proto handshake_req_alloc_proto_destroy = {\nnet/handshake/handshake-test.c:474:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-475-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake.h-9-\nnet/handshake/handshake.h:10:#ifndef _INTERNAL_HANDSHAKE_H\nnet/handshake/handshake.h:11:#define _INTERNAL_HANDSHAKE_H\nnet/handshake/handshake.h-12-\n--\nnet/handshake/handshake.h=23=enum hn_flags_bits {\nnet/handshake/handshake.h:24:\tHANDSHAKE_F_NET_DRAINING,\nnet/handshake/handshake.h-25-};\n--\nnet/handshake/handshake.h=44=enum hr_flags_bits {\nnet/handshake/handshake.h:45:\tHANDSHAKE_F_REQ_COMPLETED,\nnet/handshake/handshake.h:46:\tHANDSHAKE_F_REQ_SESSION,\nnet/handshake/handshake.h-47-};\n--\nnet/handshake/handshake.h=67=enum hp_flags_bits {\nnet/handshake/handshake.h:68:\tHANDSHAKE_F_PROTO_NOTIFY,\nnet/handshake/handshake.h-69-};\n--\nnet/handshake/handshake.h=93=bool handshake_req_cancel(struct sock sk);\nnet/handshake/handshake.h-94-\nnet/handshake/handshake.h:95:#endif /* _INTERNAL_HANDSHAKE_H /\n--\nnet/handshake/netlink.c=37=int handshake_genl_notify(struct net net, const struct handshake_proto proto,\n--\nnet/handshake/netlink.c-43-\t/ Disable notifications during unit testing /\nnet/handshake/netlink.c:44:\tif (!test_bit(HANDSHAKE_F_PROTO_NOTIFY, \u0026proto-\u003ehp_flags))\nnet/handshake/netlink.c-45-\t\treturn 0;\n--\nnet/handshake/netlink.c-55-\thdr = genlmsg_put(msg, 0, 0, \u0026handshake_nl_family, 0,\nnet/handshake/netlink.c:56:\t\t\t HANDSHAKE_CMD_READY);\nnet/handshake/netlink.c-57-\tif (!hdr)\n--\nnet/handshake/netlink.c-59-\nnet/handshake/netlink.c:60:\tif (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_HANDLER_CLASS,\nnet/handshake/netlink.c-61-\t\t\tproto-\u003ehp_handler_class) \u003c 0) {\n--\nnet/handshake/netlink.c=90=int handshake_nl_accept_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/handshake/netlink.c-101-\terr = -EINVAL;\nnet/handshake/netlink.c:102:\tif (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_ACCEPT_HANDLER_CLASS))\nnet/handshake/netlink.c-103-\t\tgoto out_status;\nnet/handshake/netlink.c:104:\tclass = nla_get_u32(info-\u003eattrs[HANDSHAKE_A_ACCEPT_HANDLER_CLASS]);\nnet/handshake/netlink.c-105-\n--\nnet/handshake/netlink.c=133=int handshake_nl_done_doit(struct sk_buff skb, struct genl_info info)\n--\nnet/handshake/netlink.c-139-\nnet/handshake/netlink.c:140:\tif (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_DONE_SOCKFD))\nnet/handshake/netlink.c-141-\t\treturn -EINVAL;\nnet/handshake/netlink.c:142:\tfd = nla_get_s32(info-\u003eattrs[HANDSHAKE_A_DONE_SOCKFD]);\nnet/handshake/netlink.c-143-\n--\nnet/handshake/netlink.c-158-\tstatus = -EIO;\nnet/handshake/netlink.c:159:\tif (info-\u003eattrs[HANDSHAKE_A_DONE_STATUS])\nnet/handshake/netlink.c:160:\t\tstatus = -(int)nla_get_u32(info-\u003eattrs[HANDSHAKE_A_DONE_STATUS]);\nnet/handshake/netlink.c-161-\n--\nnet/handshake/netlink.c=191=static void __net_exit handshake_net_exit(struct net net)\n--\nnet/handshake/netlink.c-202-\tspin_lock_bh(\u0026hn-\u003ehn_lock);\nnet/handshake/netlink.c:203:\tset_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags);\nnet/handshake/netlink.c-204-\tlist_splice_init(\u0026hn-\u003ehn_requests, \u0026requests);\n--\nnet/handshake/request.c=109=struct handshake_req handshake_req_alloc(const struct handshake_proto proto,\n--\nnet/handshake/request.c-115-\t\treturn NULL;\nnet/handshake/request.c:116:\tif (proto-\u003ehp_handler_class \u003c= HANDSHAKE_HANDLER_CLASS_NONE)\nnet/handshake/request.c-117-\t\treturn NULL;\nnet/handshake/request.c:118:\tif (proto-\u003ehp_handler_class \u003e= HANDSHAKE_HANDLER_CLASS_MAX)\nnet/handshake/request.c-119-\t\treturn NULL;\n--\nnet/handshake/request.c=169=static bool remove_pending(struct handshake_net hn, struct handshake_req req)\n--\nnet/handshake/request.c-173-\tspin_lock_bh(\u0026hn-\u003ehn_lock);\nnet/handshake/request.c:174:\tif (!test_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags) \u0026\u0026\nnet/handshake/request.c-175-\t !list_empty(\u0026req-\u003ehr_list)) {\n--\nnet/handshake/request.c=251=int handshake_req_submit(struct socket sock, struct handshake_req req,\n--\nnet/handshake/request.c-290-\tret = -EOPNOTSUPP;\nnet/handshake/request.c:291:\tif (test_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags))\nnet/handshake/request.c-292-\t\tgoto out_unlock;\n--\nnet/handshake/request.c-313-\ttrace_handshake_submit_err(net, req, req-\u003ehr_sk, ret);\nnet/handshake/request.c:314:\tif (!test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-315-\t\t/* Restore original destructor so socket teardown still runs. /\n--\nnet/handshake/request.c=324=void handshake_complete(struct handshake_req req, int status,\n--\nnet/handshake/request.c-329-\nnet/handshake/request.c:330:\tif (!test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-331-\t\tstruct file file = req-\u003ehr_file;\n--\nnet/handshake/request.c=352=bool handshake_req_cancel(struct sock sk)\n--\nnet/handshake/request.c-367-\t\t/* Request hadn't been accepted - mark cancelled /\nnet/handshake/request.c:368:\t\tif (test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-369-\t\t\ttrace_handshake_cancel_busy(net, req, sk);\n--\nnet/handshake/request.c-373-\t}\nnet/handshake/request.c:374:\tif (test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-375-\t\t/ Request already completed /\n--\nnet/handshake/tlshd.c=61=static void tls_handshake_remote_peerids(struct tls_handshake_req treq,\n--\nnet/handshake/tlshd.c-70-\tnla_for_each_attr(nla, head, len, rem) {\nnet/handshake/tlshd.c:71:\t\tif (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)\nnet/handshake/tlshd.c-72-\t\t\ti++;\n--\nnet/handshake/tlshd.c-80-\tnla_for_each_attr(nla, head, len, rem) {\nnet/handshake/tlshd.c:81:\t\tif (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)\nnet/handshake/tlshd.c-82-\t\t\ttreq-\u003eth_peerid[i++] = nla_get_u32(nla);\n--\nnet/handshake/tlshd.c=95=static void tls_handshake_done(struct handshake_req req,\n--\nnet/handshake/tlshd.c-104-\tif (!status)\nnet/handshake/tlshd.c:105:\t\tset_bit(HANDSHAKE_F_REQ_SESSION, \u0026req-\u003ehr_flags);\nnet/handshake/tlshd.c-106-\n--\nnet/handshake/tlshd.c=151=static int tls_handshake_put_peer_identity(struct sk_buff msg,\n--\nnet/handshake/tlshd.c-156-\tfor (i = 0; i \u003c treq-\u003eth_num_peerids; i++)\nnet/handshake/tlshd.c:157:\t\tif (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_PEER_IDENTITY,\nnet/handshake/tlshd.c-158-\t\t\t\ttreq-\u003eth_peerid[i]) \u003c 0)\n--\nnet/handshake/tlshd.c=163=static int tls_handshake_put_certificate(struct sk_buff msg,\n--\nnet/handshake/tlshd.c-171-\nnet/handshake/tlshd.c:172:\tentry_attr = nla_nest_start(msg, HANDSHAKE_A_ACCEPT_CERTIFICATE);\nnet/handshake/tlshd.c-173-\tif (!entry_attr)\n--\nnet/handshake/tlshd.c-175-\nnet/handshake/tlshd.c:176:\tif (nla_put_s32(msg, HANDSHAKE_A_X509_CERT,\nnet/handshake/tlshd.c-177-\t\t\ttreq-\u003eth_certificate) \|\|\nnet/handshake/tlshd.c:178:\t nla_put_s32(msg, HANDSHAKE_A_X509_PRIVKEY,\nnet/handshake/tlshd.c-179-\t\t\ttreq-\u003eth_privkey)) {\n--\nnet/handshake/tlshd.c=196=static int tls_handshake_accept(struct handshake_req req,\n--\nnet/handshake/tlshd.c-215-\nnet/handshake/tlshd.c:216:\tret = nla_put_s32(msg, HANDSHAKE_A_ACCEPT_SOCKFD, fd);\nnet/handshake/tlshd.c-217-\tif (ret \u003c 0)\nnet/handshake/tlshd.c-218-\t\tgoto out_cancel;\nnet/handshake/tlshd.c:219:\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, treq-\u003eth_type);\nnet/handshake/tlshd.c-220-\tif (ret \u003c 0)\n--\nnet/handshake/tlshd.c-222-\tif (treq-\u003eth_peername) {\nnet/handshake/tlshd.c:223:\t\tret = nla_put_string(msg, HANDSHAKE_A_ACCEPT_PEERNAME,\nnet/handshake/tlshd.c-224-\t\t\t\t treq-\u003eth_peername);\n--\nnet/handshake/tlshd.c-228-\tif (treq-\u003eth_timeout_ms) {\nnet/handshake/tlshd.c:229:\t\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_TIMEOUT, treq-\u003eth_timeout_ms);\nnet/handshake/tlshd.c-230-\t\tif (ret \u003c 0)\n--\nnet/handshake/tlshd.c-233-\tif (treq-\u003eth_keyring) {\nnet/handshake/tlshd.c:234:\t\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_KEYRING,\nnet/handshake/tlshd.c-235-\t\t\t\t treq-\u003eth_keyring);\n--\nnet/handshake/tlshd.c-239-\nnet/handshake/tlshd.c:240:\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_AUTH_MODE,\nnet/handshake/tlshd.c-241-\t\t\t treq-\u003eth_auth_mode);\n--\nnet/handshake/tlshd.c-244-\tswitch (treq-\u003eth_auth_mode) {\nnet/handshake/tlshd.c:245:\tcase HANDSHAKE_AUTH_PSK:\nnet/handshake/tlshd.c-246-\t\tret = tls_handshake_put_peer_identity(msg, treq);\n--\nnet/handshake/tlshd.c-249-\t\tbreak;\nnet/handshake/tlshd.c:250:\tcase HANDSHAKE_AUTH_X509:\nnet/handshake/tlshd.c-251-\t\tret = tls_handshake_put_certificate(msg, treq);\n--\nnet/handshake/tlshd.c=267=static const struct handshake_proto tls_handshake_proto = {\nnet/handshake/tlshd.c:268:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/tlshd.c-269-\t.hp_privsize\t\t= sizeof(struct tls_handshake_req),\nnet/handshake/tlshd.c:270:\t.hp_flags\t\t= BIT(HANDSHAKE_F_PROTO_NOTIFY),\nnet/handshake/tlshd.c-271-\n--\nnet/handshake/tlshd.c=286=int tls_client_hello_anon(const struct tls_handshake_args args, gfp_t flags)\n--\nnet/handshake/tlshd.c-294-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:295:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:296:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_UNAUTH;\nnet/handshake/tlshd.c-297-\n--\nnet/handshake/tlshd.c=312=int tls_client_hello_x509(const struct tls_handshake_args args, gfp_t flags)\n--\nnet/handshake/tlshd.c-320-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:321:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:322:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_X509;\nnet/handshake/tlshd.c-323-\ttreq-\u003eth_certificate = args-\u003eta_my_cert;\n--\nnet/handshake/tlshd.c=341=int tls_client_hello_psk(const struct tls_handshake_args args, gfp_t flags)\n--\nnet/handshake/tlshd.c-354-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:355:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:356:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_PSK;\nnet/handshake/tlshd.c-357-\ttreq-\u003eth_num_peerids = args-\u003eta_num_peerids;\n--\nnet/handshake/tlshd.c=375=int tls_server_hello_x509(const struct tls_handshake_args args, gfp_t flags)\n--\nnet/handshake/tlshd.c-383-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:384:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;\nnet/handshake/tlshd.c:385:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_X509;\nnet/handshake/tlshd.c-386-\ttreq-\u003eth_certificate = args-\u003eta_my_cert;\n--\nnet/handshake/tlshd.c=403=int tls_server_hello_psk(const struct tls_handshake_args args, gfp_t flags)\n--\nnet/handshake/tlshd.c-411-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:412:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;\nnet/handshake/tlshd.c:413:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_PSK;\nnet/handshake/tlshd.c-414-\ttreq-\u003eth_num_peerids = 1;\n--\nnet/handshake/tlshd.c=445=void tls_handshake_close(struct socket sock)\n--\nnet/handshake/tlshd.c-451-\t\treturn;\nnet/handshake/tlshd.c:452:\tif (!test_and_clear_bit(HANDSHAKE_F_REQ_SESSION, \u0026req-\u003ehr_flags))\nnet/handshake/tlshd.c-453-\t\treturn;\n--\nnet/mac80211/mlme.c=5592=const char ieee80211_get_reason_code_string(u16 reason_code)\n--\nnet/mac80211/mlme.c-5607-\tcase_WLAN(MIC_FAILURE);\nnet/mac80211/mlme.c:5608:\tcase_WLAN(4WAY_HANDSHAKE_TIMEOUT);\nnet/mac80211/mlme.c:5609:\tcase_WLAN(GROUP_KEY_HANDSHAKE_TIMEOUT);\nnet/mac80211/mlme.c-5610-\tcase_WLAN(IE_DIFFERENT);\n--\nnet/sunrpc/svc_xprt.c=224=void svc_xprt_received(struct svc_xprt xprt)\n--\nnet/sunrpc/svc_xprt.c-245-\tif (READ_ONCE(xprt-\u003expt_flags) \u0026\nnet/sunrpc/svc_xprt.c:246:\t (BIT(XPT_CONN) \| BIT(XPT_CLOSE) \| BIT(XPT_HANDSHAKE) \|\nnet/sunrpc/svc_xprt.c-247-\t BIT(XPT_DATA) \| BIT(XPT_DEFERRED)))\n--\nnet/sunrpc/svc_xprt.c=472=static bool svc_xprt_ready(struct svc_xprt xprt)\n--\nnet/sunrpc/svc_xprt.c-489-\t\treturn false;\nnet/sunrpc/svc_xprt.c:490:\tif (xpt_flags \u0026 (BIT(XPT_CONN) \| BIT(XPT_CLOSE) \| BIT(XPT_HANDSHAKE)))\nnet/sunrpc/svc_xprt.c-491-\t\treturn true;\n--\nnet/sunrpc/svc_xprt.c=832=static void svc_handle_xprt(struct svc_rqst rqstp, struct svc_xprt xprt)\n--\nnet/sunrpc/svc_xprt.c-860-\t\tsvc_xprt_received(xprt);\nnet/sunrpc/svc_xprt.c:861:\t} else if (test_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags)) {\nnet/sunrpc/svc_xprt.c-862-\t\txprt-\u003expt_ops-\u003expo_handshake(xprt);\n--\nnet/sunrpc/svcauth_unix.c=1101=svcauth_tls_accept(struct svc_rqst rqstp)\n--\nnet/sunrpc/svcauth_unix.c-1147-\nnet/sunrpc/svcauth_unix.c:1148:\t\tset_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcauth_unix.c-1149-\t\tsvc_xprt_enqueue(xprt);\n--\nnet/sunrpc/svcsock.c=85=enum {\nnet/sunrpc/svcsock.c:86:\tSVC_HANDSHAKE_TO\t= 5U * HZ\nnet/sunrpc/svcsock.c-87-};\n--\nnet/sunrpc/svcsock.c=401=static void svc_data_ready(struct sock sk)\n--\nnet/sunrpc/svcsock.c-411-\t\ttrace_svcsock_data_ready(\u0026svsk-\u003esk_xprt, 0);\nnet/sunrpc/svcsock.c:412:\t\tif (test_bit(XPT_HANDSHAKE, \u0026svsk-\u003esk_xprt.xpt_flags))\nnet/sunrpc/svcsock.c-413-\t\t\treturn;\n--\nnet/sunrpc/svcsock.c=462=static void svc_tcp_handshake_done(void data, int status, key_serial_t peerid)\n--\nnet/sunrpc/svcsock.c-471-\t}\nnet/sunrpc/svcsock.c:472:\tclear_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcsock.c-473-\tcomplete_all(\u0026svsk-\u003esk_handshake_done);\n--\nnet/sunrpc/svcsock.c=482=static void svc_tcp_handshake(struct svc_xprt xprt)\n--\nnet/sunrpc/svcsock.c-508-\tret = wait_for_completion_interruptible_timeout(\u0026svsk-\u003esk_handshake_done,\nnet/sunrpc/svcsock.c:509:\t\t\t\t\t\t\tSVC_HANDSHAKE_TO);\nnet/sunrpc/svcsock.c-510-\tif (ret \u003c= 0) {\n--\nnet/sunrpc/svcsock.c-537-out_failed:\nnet/sunrpc/svcsock.c:538:\tclear_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcsock.c-539-\tset_bit(XPT_DATA, \u0026xprt-\u003expt_flags);\n--\nnet/sunrpc/xprtsock.c=110=static struct ctl_table xs_tunables_table[] = {\n--\nnet/sunrpc/xprtsock.c-196- /\nnet/sunrpc/xprtsock.c:197:#define XS_TLS_HANDSHAKE_TO\t(10U * HZ)\nnet/sunrpc/xprtsock.c-198-\n--\nnet/sunrpc/xprtsock.c=2616=static int xs_tls_handshake_sync(struct rpc_xprt lower_xprt, struct xprtsec_parms xprtsec)\n--\nnet/sunrpc/xprtsock.c-2650-\trc = wait_for_completion_interruptible_timeout(\u0026lower_transport-\u003ehandshake_done,\nnet/sunrpc/xprtsock.c:2651:\t\t\t\t\t\t XS_TLS_HANDSHAKE_TO);\nnet/sunrpc/xprtsock.c-2652-\tif (rc \u003c= 0) {\n--\nnet/tls/tls_sw.c=1531=static int tls_check_pending_rekey(struct sock sk, struct tls_context ctx,\n--\nnet/tls/tls_sw.c-1538-\nnet/tls/tls_sw.c:1539:\tif (likely(tlm-\u003econtrol != TLS_RECORD_TYPE_HANDSHAKE))\nnet/tls/tls_sw.c-1540-\t\treturn 0;\n--\nnet/tls/tls_sw.c-1550-\nnet/tls/tls_sw.c:1551:\tif (hs_type == TLS_HANDSHAKE_KEYUPDATE) {\nnet/tls/tls_sw.c-1552-\t\tstruct tls_sw_context_rx rx_ctx = ctx-\u003epriv_ctx_rx;\n--\nnet/wireless/core.c=853=int wiphy_register(struct wiphy wiphy)\n--\nnet/wireless/core.c-968-\tif (WARN_ON(wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/core.c:969:\t\t\t\t\t NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X) \u0026\u0026\nnet/wireless/core.c-970-\t\t (!rdev-\u003eops-\u003eset_pmk \|\| !rdev-\u003eops-\u003edel_pmk)))\n--\nnet/wireless/nl80211.c=1128=nl80211_wowlan_policy[NUM_NL80211_WOWLAN_TRIG] = {\n--\nnet/wireless/nl80211.c-1134-\t[NL80211_WOWLAN_TRIG_EAP_IDENT_REQUEST] = { .type = NLA_FLAG },\nnet/wireless/nl80211.c:1135:\t[NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE] = { .type = NLA_FLAG },\nnet/wireless/nl80211.c-1136-\t[NL80211_WOWLAN_TRIG_RFKILL_RELEASE] = { .type = NLA_FLAG },\n--\nnet/wireless/nl80211.c=2068=static int nl80211_send_wowlan(struct sk_buff msg,\n--\nnet/wireless/nl80211.c-2093-\t nla_put_flag(msg, NL80211_WOWLAN_TRIG_EAP_IDENT_REQUEST)) \|\|\nnet/wireless/nl80211.c:2094:\t ((rdev-\u003ewiphy.wowlan-\u003eflags \u0026 WIPHY_WOWLAN_4WAY_HANDSHAKE) \u0026\u0026\nnet/wireless/nl80211.c:2095:\t nla_put_flag(msg, NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE)) \|\|\nnet/wireless/nl80211.c-2096-\t ((rdev-\u003ewiphy.wowlan-\u003eflags \u0026 WIPHY_WOWLAN_RFKILL_RELEASE) \u0026\u0026\n--\nnet/wireless/nl80211.c=12936=static int nl80211_crypto_settings(struct cfg80211_registered_device rdev,\n--\nnet/wireless/nl80211.c-13026-\t\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:13027:\t\t\t\t\t NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK) \u0026\u0026\nnet/wireless/nl80211.c-13028-\t\t !wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:13029:\t\t\t\t\t NL80211_EXT_FEATURE_4WAY_HANDSHAKE_AP_PSK))\nnet/wireless/nl80211.c-13030-\t\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=13995=static int nl80211_connect(struct sk_buff skb, struct genl_info info)\n--\nnet/wireless/nl80211.c-14023-\t !wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:14024:\t\t\t\t NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X))\nnet/wireless/nl80211.c-14025-\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=15563=static int nl80211_get_wowlan(struct sk_buff skb, struct genl_info info)\n--\nnet/wireless/nl80211.c-15608-\t\t (rdev-\u003ewiphy.wowlan_config-\u003efour_way_handshake \u0026\u0026\nnet/wireless/nl80211.c:15609:\t\t nla_put_flag(msg, NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE)) \|\|\nnet/wireless/nl80211.c-15610-\t\t (rdev-\u003ewiphy.wowlan_config-\u003erfkill_release \u0026\u0026\n--\nnet/wireless/nl80211.c=15813=static int nl80211_set_wowlan(struct sk_buff skb, struct genl_info info)\n--\nnet/wireless/nl80211.c-15875-\nnet/wireless/nl80211.c:15876:\tif (tb[NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE]) {\nnet/wireless/nl80211.c:15877:\t\tif (!(wowlan-\u003eflags \u0026 WIPHY_WOWLAN_4WAY_HANDSHAKE))\nnet/wireless/nl80211.c-15878-\t\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=18434=static int nl80211_set_pmk(struct sk_buff skb, struct genl_info info)\n--\nnet/wireless/nl80211.c-18445-\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:18446:\t\t\t\t NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X))\nnet/wireless/nl80211.c-18447-\t\treturn -EOPNOTSUPP;\n--\nnet/wireless/nl80211.c=18472=static int nl80211_del_pmk(struct sk_buff skb, struct genl_info info)\n--\nnet/wireless/nl80211.c-18483-\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\n\n" }
55/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 55597 output: 20 thoughts: 1628 Thoughts: Identifying Relevant Symbols for Targeted Fuzzing Okay, let's break this down systematically. My goal here is to identify the most relevant functions in the kernel modifications for fuzzing, specifically focusing on the new handshake code. First, let's start by looking at `net/handshake/Kconfig` to confirm that `CONFIG_NET_HANDSHAKE` is enabled. Next, I'll need a list of the required configurations to compile the code. The following configurations are needed: `VFS`, `EVENTFD`, `EPOLL`, `USERFAULTFD`, `BPF_SYSCALL`, `NTSYNC`, `KCM`, `GPIO_CDEV`, `IO_URING`, `MEDIA_SUPPORT`, `NET_HANDSHAKE`, and `XFS_FS`. Now, the crucial step: identifying the right symbols to target. I need to avoid the fuzzing trap of picking overly generic, "ubiquitous" functions like `sys_openat` or `do_sys_openat2`, which will dilute the fuzzing effort. Instead, I want to find the feature-specific entrypoints or functions that specifically implement the new logic. Following the guidance, I need to look for functions that implement the logic being added or altered. My focus is on functions in .c files. Let's start by methodically reviewing each function: 1. `receive_fd` (`fs/file.c`): This isn't ubiquitous; it's specific to file descriptor passing via `scm_detach_fds`, `pidfd_getfd`, `seccomp_handle_addfd`, `io_install_fixed_fd`, and `vduse`. This looks promising. 2. `scm_recv_one_fd` (`net/core/scm.c`): Again, not ubiquitous. This is dedicated to passing file descriptors across UNIX domain sockets (SCM_RIGHTS). Good candidate. 3. `do_eventfd` or `__do_sys_eventfd2` (`fs/eventfd.c`): I need to be careful with inlined functions. Based on how `SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)` is defined, I see that `__do_sys_eventfd2` is the syscall symbol. 4. `__do_sys_open_tree_attr` (`fs/namespace.c`) and `__do_sys_fsmount` (`fs/namespace.c`): These look like strong candidates as system calls. 5. `bpf_iter_new_fd` (`kernel/bpf/bpf_iter.c`): Worth checking. 6. `bpf_token_create` (`kernel/bpf/token.c`): Worth checking. 7. `new_userfaultfd` or `__do_sys_userfaultfd` (`mm/userfaultfd.c`): The syscall symbol looks like `__do_sys_userfaultfd`. 8. `xfs_open_by_handle` (`fs/xfs/xfs_handle.c`): Potentially relevant. 9. `kcm_ioctl` (`net/kcm/kcmsock.c`): Could be valuable. 10. `ntsync_obj_get_fd` (`drivers/misc/ntsync.c`): Let's keep it on the list. 11. `media_request_alloc` (`drivers/media/mc/mc-request.c`): Relevant. 12. `handshake_nl_accept_doit` (`net/handshake/netlink.c`): This is very relevant given the area we are focusing on. 13. `io_create_mock_file` (`io_uring/mock_file.c`): Interesting, depending on its use within the modified code. 14. `linehandle_create` (`drivers/gpio/gpiolib-cdev.c`): Possibly relevant. I need to confirm whether these functions have reliable symbol names in the kernel's vmlinux, specifically syscalls. Modern x86_64 Linux system calls defined with `SYSCALL_DEFINE...` typically use names like `__x64_sys_fsmount`, and `__do_sys_fsmount`. The key is to distinguish syscalls from internal functions, so the fuzzing tools can find them. Other functions: `receive_fd`, `scm_recv_one_fd`, `bpf_iter_new_fd`, `bpf_token_create`, `xfs_open_by_handle`, `media_request_
56/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "bpf_token_create" } Results: { "Output": "include/linux/bpf.h=2909=void bpf_token_put(struct bpf_token token);\ninclude/linux/bpf.h:2910:int bpf_token_create(union bpf_attr attr);\ninclude/linux/bpf.h-2911-struct bpf_token bpf_token_get_from_fd(u32 ufd);\n--\ninclude/linux/lsm_hook_defs.h=449=LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free, struct bpf_prog prog)\ninclude/linux/lsm_hook_defs.h:450:LSM_HOOK(int, 0, bpf_token_create, struct bpf_token token, union bpf_attr attr,\ninclude/linux/lsm_hook_defs.h-451-\t const struct path path)\n--\ninclude/linux/security.h=2309=extern void security_bpf_prog_free(struct bpf_prog prog);\ninclude/linux/security.h:2310:extern int security_bpf_token_create(struct bpf_token token, union bpf_attr attr,\ninclude/linux/security.h-2311-\t\t\t\t const struct path path);\n--\ninclude/linux/security.h=2347=static inline void security_bpf_prog_free(struct bpf_prog prog)\n--\ninclude/linux/security.h-2349-\ninclude/linux/security.h:2350:static inline int security_bpf_token_create(struct bpf_token token, union bpf_attr attr,\ninclude/linux/security.h-2351-\t\t\t\t\t const struct path path)\n--\nkernel/bpf/bpf_lsm.c=297=BTF_ID(func, bpf_lsm_bpf_prog_load)\nkernel/bpf/bpf_lsm.c:298:BTF_ID(func, bpf_lsm_bpf_token_create)\nkernel/bpf/bpf_lsm.c-299-BTF_ID(func, bpf_lsm_bpf_token_free)\n--\nkernel/bpf/syscall.c=6226=static int token_create(union bpf_attr attr)\n--\nkernel/bpf/syscall.c-6234-\nkernel/bpf/syscall.c:6235:\treturn bpf_token_create(attr);\nkernel/bpf/syscall.c-6236-}\n--\nkernel/bpf/token.c=107=const struct file_operations bpf_token_fops = {\n--\nkernel/bpf/token.c-111-\nkernel/bpf/token.c:112:int bpf_token_create(union bpf_attr attr)\nkernel/bpf/token.c-113-{\n--\nkernel/bpf/token.c-187-\nkernel/bpf/token.c:188:\terr = security_bpf_token_create(token, attr, \u0026path);\nkernel/bpf/token.c-189-\tif (err)\n--\nsecurity/security.c=5370=int security_bpf_prog_load(struct bpf_prog prog, union bpf_attr attr,\n--\nsecurity/security.c-5385-/\nsecurity/security.c:5386: security_bpf_token_create() - Check if creating of BPF token is allowed\nsecurity/security.c-5387- * @token: BPF token object\n--\nsecurity/security.c-5395- /\nsecurity/security.c:5396:int security_bpf_token_create(struct bpf_token token, union bpf_attr attr,\nsecurity/security.c-5397-\t\t\t const struct path path)\n--\nsecurity/security.c-5404-\nsecurity/security.c:5405:\trc = call_int_hook(bpf_token_create, token, attr, path);\nsecurity/security.c-5406-\tif (unlikely(rc))\n--\nsecurity/selinux/hooks.c=7306=static int selinux_bpf_prog_load(struct bpf_prog prog, union bpf_attr attr,\n--\nsecurity/selinux/hooks.c-7326-\nsecurity/selinux/hooks.c:7327:static int selinux_bpf_token_create(struct bpf_token token,\nsecurity/selinux/hooks.c-7328-\t\t\t\t union bpf_attr attr,\n--\nsecurity/selinux/hooks.c=7560=static struct security_hook_list selinux_hooks[] __ro_after_init = {\n--\nsecurity/selinux/hooks.c-7842-\tLSM_HOOK_INIT(bpf_prog_load, selinux_bpf_prog_load),\nsecurity/selinux/hooks.c:7843:\tLSM_HOOK_INIT(bpf_token_create, selinux_bpf_token_create),\nsecurity/selinux/hooks.c-7844-\tLSM_HOOK_INIT(bpf_token_cmd, selinux_bpf_token_cmd),\n--\ntools/lib/bpf/bpf.c=1411=int bpf_prog_bind_map(int prog_fd, int map_fd,\n--\ntools/lib/bpf/bpf.c-1429-\ntools/lib/bpf/bpf.c:1430:int bpf_token_create(int bpffs_fd, struct bpf_token_create_opts opts)\ntools/lib/bpf/bpf.c-1431-{\n--\ntools/lib/bpf/bpf.c-1435-\ntools/lib/bpf/bpf.c:1436:\tif (!OPTS_VALID(opts, bpf_token_create_opts))\ntools/lib/bpf/bpf.c-1437-\t\treturn libbpf_err(-EINVAL);\n--\ntools/lib/bpf/bpf.h=717=LIBBPF_API int bpf_prog_test_run_opts(int prog_fd,\n--\ntools/lib/bpf/bpf.h-719-\ntools/lib/bpf/bpf.h:720:struct bpf_token_create_opts {\ntools/lib/bpf/bpf.h-721-\tsize_t sz; / size of this struct for forward/backward compatibility /\n--\ntools/lib/bpf/bpf.h-724-};\ntools/lib/bpf/bpf.h:725:#define bpf_token_create_opts__last_field flags\ntools/lib/bpf/bpf.h-726-\ntools/lib/bpf/bpf.h-727-/\ntools/lib/bpf/bpf.h:728: @brief bpf_token_create() creates a new instance of BPF token derived\ntools/lib/bpf/bpf.h-729- * from specified BPF FS mount point.\n--\ntools/lib/bpf/bpf.h-740- /\ntools/lib/bpf/bpf.h:741:LIBBPF_API int bpf_token_create(int bpffs_fd,\ntools/lib/bpf/bpf.h:742:\t\t\t\tstruct bpf_token_create_opts opts);\ntools/lib/bpf/bpf.h-743-\n--\ntools/lib/bpf/libbpf.c=5147=static int bpf_object_prepare_token(struct bpf_object obj)\n--\ntools/lib/bpf/libbpf.c-5172-\ntools/lib/bpf/libbpf.c:5173:\ttoken_fd = bpf_token_create(bpffs_fd, 0);\ntools/lib/bpf/libbpf.c-5174-\tclose(bpffs_fd);\n--\ntools/lib/bpf/libbpf.map=411=LIBBPF_1.4.0 {\n--\ntools/lib/bpf/libbpf.map-414-\t\tbpf_raw_tracepoint_open_opts;\ntools/lib/bpf/libbpf.map:415:\t\tbpf_token_create;\ntools/lib/bpf/libbpf.map-416-\t\tbtf__new_split;\n--\ntools/testing/selftests/bpf/prog_tests/token.c=287=static void child(int sock_fd, struct bpffs_opts opts, child_callback_fn callback)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-389-\t/* create BPF token FD and pass it to parent for some extra checks /\ntools/testing/selftests/bpf/prog_tests/token.c:390:\ttoken_fd = bpf_token_create(bpffs_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-391-\tif (!ASSERT_GT(token_fd, 0, \"child_token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=506=static int userns_map_create(int mnt_fd, struct token_lsm lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-512-\t/* create BPF token from BPF FS mount /\ntools/testing/selftests/bpf/prog_tests/token.c:513:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-514-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=574=static int userns_btf_load(int mnt_fd, struct token_lsm lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-583-\t/* create BPF token from BPF FS mount /\ntools/testing/selftests/bpf/prog_tests/token.c:584:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-585-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=643=static int userns_prog_load(int mnt_fd, struct token_lsm lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-659-\t/* create BPF token from BPF FS mount /\ntools/testing/selftests/bpf/prog_tests/token.c:660:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-661-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=1108=static int userns_bpf_token_info(int mnt_fd, struct token_lsm lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-1114-\t/* create BPF token from BPF FS mount */\ntools/testing/selftests/bpf/prog_tests/token.c:1115:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-1116-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n" }
57/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 61354 output: 26 thoughts: 591 Thoughts: My Analysis of FD_PREPARE Updates Okay, so I've been digging into where `FD_PREPARE` was updated, and I've got a pretty good list. It looks like the changes are in key functions across various parts of the kernel: `bpf_token_create` in `kernel/bpf/token.c`, `bpf_iter_new_fd` in `kernel/bpf/bpf_iter.c`, `receive_fd` in `fs/file.c`, `scm_recv_one_fd` in `net/core/scm.c`, `new_userfaultfd` in `mm/userfaultfd.c`, `do_epoll_create` in `fs/eventpoll.c`, `do_eventfd` in `fs/eventfd.c`, `ntsync_obj_get_fd` in `drivers/misc/ntsync.c`, `media_request_alloc` in `drivers/media/mc/mc-request.c` and `xfs_open_by_handle` in `fs/xfs/xfs_handle.c`. Now, the next logical step is to understand the configuration implications of these updates. I need to figure out which kernel configuration options enable these code paths. So, based on my analysis of the dependencies, it looks like: * `receive_fd` and `scm_recv_one_fd` are pretty fundamental – they rely on core networking and file system code, which implies `NET` for the network component. * `bpf_token_create` and `bpf_iter_new_fd` depend on `BPF_SYSCALL`. * `new_userfaultfd` depends on `USERFAULTFD`. * `ntsync_obj_get_fd` relies on `NTSYNC`. * `media_request_alloc` depends on `MEDIA_SUPPORT` and `MEDIA_CONTROLLER`. * `xfs_open_by_handle` depends on `XFS_FS`. Given the importance of `USERFAULTFD`, I need to double-check its direct dependencies. I will have a more informed next step with that information.
58/2	2026/09/19 01:39	tool	grepper	0m Error: no matches Args: { "Expression": "config USERFAULTFD", "PathPrefix": "fs/" } Results: { "error": "no matches" }
59/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 62469 output: 18 thoughts: 10 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Hunting Down USERFAULTFD Configuration Okay, so I need to dig into the `USERFAULTFD` configuration. My initial thought process is to bypass the usual suspects, and just start looking for it directly. I'm not going to beat around the bush; I'm going to jump straight to the relevant configuration settings. I'm thinking of kernel parameters, sysfs entries, maybe even some obscure module options if it's got one. I'm assuming, given what I'm working on, that the configuration would have been carefully considered given the nature of the feature so it would be likely available to change at runtime. I'll need to figure out what's currently enabled or disabled. My guess is it's not something that's simply on by default, so I'll probably be chasing down some disabled state, or specific access permissions. I'll focus on the obvious first, but be ready to drop into the code if it's not as simple as a sysctl entry. I'll be looking for relevant kernel builds and patches too, that could also give me an idea about the configuration.
60/2	2026/09/19 01:39	tool	grepper	0m Args: { "Expression": "config USERFAULTFD" } Results: { "Output": "mm/Kconfig=1372=config HAVE_ARCH_USERFAULTFD_MINOR\n--\nmm/Kconfig-1376-\nmm/Kconfig:1377:config USERFAULTFD_RWP\nmm/Kconfig-1378-\tdef_bool y\n--\nmm/Kconfig-1385-\nmm/Kconfig:1386:menuconfig USERFAULTFD\nmm/Kconfig-1387-\tbool \"Enable userfaultfd() system call\"\n" }
61/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 62880 output: 33 thoughts: 17 Thoughts: Here's a summary of my thought process, as requested: Navigating the Labyrinth of Kernel Configuration Okay, time to dive into this. Based on the task at hand, I'm thinking I need to zero in on `mm/Kconfig`. That's where a lot of the memory management options and dependencies are defined in the kernel's configuration system, so it's a good starting point for whatever I'm troubleshooting or investigating. And since there's a specific line number mentioned, I'm going to start around line 1386. That likely points to a specific configuration option, definition, or perhaps a conditional block related to the memory management subsystem. Going directly to that location will save some time rather than sifting through the file from the start. Let's see what's there...
62/2	2026/09/19 01:39	tool	read-file	0m Args: { "File": "mm/Kconfig", "FirstLine": 1385, "LineCount": 10 } Results: { "Contents": "1385:\t\n1386:\tmenuconfig USERFAULTFD\n1387:\t\tbool \"Enable userfaultfd() system call\"\n1388:\t\tdepends on MMU\n1389:\t\thelp\n1390:\t\t Enable the userfaultfd() system call that allows to intercept and\n1391:\t\t handle page faults in userland.\n1392:\t\n1393:\tconfig PTE_MARKER_UFFD_WP\n1394:\t\tbool \"Userfaultfd write protection support for shmem/hugetlbfs\"\n" }
63/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 63256 output: 29 thoughts: 19 Thoughts: Here's my summary, as though I'm thinking it: Digging into Kernel Configuration for BPF Syscall Alright, time to get my hands dirty. I need to refresh my memory on the kernel config options related to BPF syscalls, particularly `BPF_SYSCALL`. Let's jump into the `init/Kconfig` file and take a look. I'm assuming that's where I can find the primary switch for enabling or disabling that functionality, as it's the usual spot for such core features. I need to verify that it's enabled and consider any dependencies or associated options that might be relevant to the specific BPF use-case I'm working on right now. A quick check of the Kconfig should clarify things.
64/2	2026/09/19 01:39	tool	grepper	0m Error: no matches Args: { "Expression": "config BPF_SYSCALL", "PathPrefix": "init/" } Results: { "error": "no matches" }
65/2	2026/09/19 01:39	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 63481 output: 21 thoughts: 13 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Hunting Down BPF_SYSCALL in the Configuration Alright, let's get down to brass tacks. I need to locate the `config BPF_SYSCALL` option. This isn't just a casual search; I need to quickly and efficiently pinpoint its definition within the kernel configuration system. This usually means diving into the Kconfig files, likely spread across various subdirectories reflecting different kernel subsystems. I'm thinking I'll start with a broad search – maybe using `grep` or a similar tool to look across the entire kernel source tree, or the generated `.config` file itself if I have it at hand. That'll give me a quick list of places where `BPF_SYSCALL` is even mentioned. From there, I'll need to assess the context. Where it's defined, the dependencies it has, and perhaps where it's used by other configurations, or code. Context is key here; a simple grep hit isn't enough. I'm looking for the definitive source and any relevant dependencies. So, time to get searching and then start understanding.
66/2	2026/09/19 01:40	tool	grepper	0m Args: { "Expression": "config BPF_SYSCALL" } Results: { "Output": "kernel/bpf/Kconfig=25=menu \"BPF subsystem\"\nkernel/bpf/Kconfig-26-\nkernel/bpf/Kconfig:27:config BPF_SYSCALL\nkernel/bpf/Kconfig-28-\tbool \"Enable bpf() system call\"\n" }
67/2	2026/09/19 01:40	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 63851 output: 34 thoughts: 19 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Examining BPF Kconfig Configuration Okay, I need to dive into the kernel's BPF configuration. My initial instinct is to go straight to `kernel/bpf/Kconfig`, specifically around line 27. I'm probably looking for the core BPF feature enablement flag, or maybe I'm trying to recall a related option that I want to double-check. Could be an experimental feature flag, or something tied to a specific BPF helper version. I suspect line 27 will likely lead me to the main entry point or a crucial dependency in that Kconfig file. I am hoping to get to the root cause of an issue I'm working through. I'm expecting this to provide the base configuration that all further configuration is reliant on. Time to see what's there and refresh my memory on the build options.
68/2	2026/09/19 01:40	tool	read-file	0m Args: { "File": "kernel/bpf/Kconfig", "FirstLine": 25, "LineCount": 15 } Results: { "Contents": " 25:\tmenu \"BPF subsystem\"\n 26:\t\n 27:\tconfig BPF_SYSCALL\n 28:\t\tbool \"Enable bpf() system call\"\n 29:\t\tselect BPF\n 30:\t\tselect IRQ_WORK\n 31:\t\tselect NEED_TASKS_RCU\n 32:\t\tselect TASKS_TRACE_RCU\n 33:\t\tselect BINARY_PRINTF\n 34:\t\tselect NET_SOCK_MSG if NET\n 35:\t\tselect NET_XGRESS if NET\n 36:\t\tselect PAGE_POOL if NET\n 37:\t\tdefault n\n 38:\t\thelp\n 39:\t\t Enable the bpf() system call that allows to manipulate BPF programs\n" }
69/2	2026/09/19 01:40	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 64294 output: 19 thoughts: 11 Thoughts: Here's your summary, as if it were my thought process: Diving into Configuration: NTSYNC Alright, time to get granular. I need to take a look at the `config NTSYNC` settings. I know this is where the core network time synchronization parameters are. I'm going to want to examine how this system is configured to interact with the NTP servers, and what specific settings are enabled. I'll need to confirm the configured server addresses, the authentication details if any, and the configured stratum level, to assess the accuracy of time synchronization with external servers. I need to make sure this NTSYNC setting is optimally configured to prevent any time drift or synchronization issues within the system. Let's see what we're working with here.
70/2	2026/09/19 01:40	tool	grepper	0m Args: { "Expression": "config NTSYNC" } Results: { "Output": "drivers/misc/Kconfig=441=config OPEN_DICE\n--\ndrivers/misc/Kconfig-453-\ndrivers/misc/Kconfig:454:config NTSYNC\ndrivers/misc/Kconfig-455-\ttristate \"NT synchronization primitive emulation\"\n" }
71/2	2026/09/19 01:40	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 64570 output: 34 thoughts: 18 Thoughts: Here's my take on the thought process, as if it were my own: Diving into the Kernel Config Okay, time to dig in. Something's nagging at me, and I have a feeling the answer lies in the kernel's configuration options. Let's start with `drivers/misc/Kconfig`. Line 454... yeah, that's where I need to be. Hopefully, whatever is bugging me is addressed within that particular section. Time to start reading...
72/2	2026/09/19 01:40	tool	read-file	0m Args: { "File": "drivers/misc/Kconfig", "FirstLine": 453, "LineCount": 10 } Results: { "Contents": " 453:\t\n 454:\tconfig NTSYNC\n 455:\t\ttristate \"NT synchronization primitive emulation\"\n 456:\t\thelp\n 457:\t\t This module provides kernel support for emulation of Windows NT\n 458:\t\t synchronization primitives. It is not a hardware driver.\n 459:\t\n 460:\t\t To compile this driver as a module, choose M here: the\n 461:\t\t module will be called ntsync.\n 462:\t\n" }
73/2	2026/09/19 01:40	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 64873 output: 17 thoughts: 9 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue: Checking the Configuration Kernel Configuration Management (KCM) Alright, time to get to the heart of the matter. I need to take a look at the `config KCM`. It's my go-to starting point when troubleshooting, especially after the recent system update. It’s where I'll find the core configurations related to how we're managing the kernel and its various parameters. I’m thinking, does the kernel configuration match the specs? Are there any obvious flags that are set wrong, particularly related to the areas affected by the recent changes? I'll probably start with the memory allocation, interrupt handling, and any power management settings. After all, a misconfigured KCM can lead to all sorts of performance bottlenecks or outright instability. It's the first place I always check to get a good overview of the state. It will allow me to narrow down the problem.
74/2	2026/09/19 01:40	tool	grepper	0m Args: { "Expression": "config KCM" } Results: { "Output": "init/Kconfig=2003=config MEMBARRIER\n--\ninit/Kconfig-2014-\ninit/Kconfig:2015:config KCMP\ninit/Kconfig-2016-\tbool \"Enable kcmp() system call\" if EXPERT\n" }
75/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 65190 output: 33 thoughts: 13 Thoughts: Here's a summary of my immediate thought process, crafted from the prompt: Kconfig Inspection: Where Do We Start? Alright, the instruction is clear: start by examining `net/kcm/Kconfig`. This immediately tells me we're likely dealing with configuration options related to a specific kernel component, namely KCM (Kernel Connection Manager, I presume?). This means it's time to delve into the heart of the configuration. I want to see how this particular KCM module is controlled. What features are exposed to the user for configuration? Are there any dependencies on other kernel components? How granular is the control, and what are the defaults? My initial goal is to understand the scope and the landscape of settings that `Kconfig` defines for this subsystem. Let's see what's in there.
76/2	2026/09/19 01:41	tool	read-file	0m Args: { "File": "net/kcm/Kconfig", "FirstLine": 1, "LineCount": 20 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\t\n 3:\tconfig AF_KCM\n 4:\t\ttristate \"KCM sockets\"\n 5:\t\tdepends on INET\n 6:\t\tselect BPF_SYSCALL\n 7:\t\tselect STREAM_PARSER\n 8:\t\thelp\n 9:\t\t KCM (Kernel Connection Multiplexor) sockets provide a method\n 10:\t\t for multiplexing messages of a message-based application\n 11:\t\t protocol over kernel connections (e.g. TCP connections).\n" }
77/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 65559 output: 29 thoughts: 37 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Kernel Media Subsystem Audit - Quick Scan Alright, that familiar string popped up: `AF_KCM`! Always catches my eye. Time for a quick sanity check within the media subsystem. My immediate thought is to verify the configuration options directly related to this area. Let's see... I'm diving into `drivers/media/Kconfig` right away. I need to confirm the status of `MEDIA_SUPPORT` and `MEDIA_CONTROLLER` in relation to this, and how `AF_KCM` influences their enablement or dependencies. I'm looking for any potential configuration conflicts or missing dependencies right off the bat, as well as a more general idea of how this part of the subsystem is handled. I need to assess its influence on a high level and make sure the design makes sense.
78/2	2026/09/19 01:41	tool	grepper	0m Args: { "Expression": "config MEDIA_CONTROLLER", "PathPrefix": "drivers/media/" } Results: { "Output": "drivers/media/Kconfig=160=config VIDEO_DEV\n--\ndrivers/media/Kconfig-169-\ndrivers/media/Kconfig:170:config MEDIA_CONTROLLER\ndrivers/media/Kconfig-171-\tbool \"Media Controller API\"\n--\ndrivers/media/mc/Kconfig-6-\ndrivers/media/mc/Kconfig:7:config MEDIA_CONTROLLER_DVB\ndrivers/media/mc/Kconfig-8-\tbool \"Enable Media controller for DVB (EXPERIMENTAL)\"\n" }
79/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 65948 output: 34 thoughts: 18 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into the Media Subsystem Configuration Okay, let's zero in on `drivers/media/Kconfig`. I need to get a handle on what's configurable within the media subsystem. I'm thinking around line 170. I suspect there's a specific option related to [your assumed area of expertise - e.g., a specific camera module, a particular video codec, or perhaps a relevant DMA engine setting]. I'm going to scan that section to see how that feature is defined, if it's tristated, what dependencies it might have on other kernel modules, and the default settings. My goal is to quickly assess its build configuration. This will give me a better understanding of what’s enabled and disabled and how that impacts my current work on [insert likely area of work, e.g. system power, device configuration, new feature integration].
80/2	2026/09/19 01:41	tool	read-file	0m Args: { "File": "drivers/media/Kconfig", "FirstLine": 165, "LineCount": 20 } Results: { "Contents": " 165:\t\tselect VIDEOBUF2_V4L2 if VIDEOBUF2_CORE\n 166:\t\thelp\n 167:\t\t Enables the V4L2 API, used by cameras, analog TV, video grabbers,\n 168:\t\t radio devices and by some input devices.\n 169:\t\n 170:\tconfig MEDIA_CONTROLLER\n 171:\t\tbool \"Media Controller API\"\n 172:\t\tdefault MEDIA_CAMERA_SUPPORT \|\| MEDIA_ANALOG_TV_SUPPORT \|\| MEDIA_DIGITAL_TV_SUPPORT \|\| MEDIA_PLATFORM_SUPPORT\n 173:\t\thelp\n 174:\t\t Enable the media controller API used to query media devices internal\n 175:\t\t topology and configure it dynamically.\n 176:\t\n 177:\t\t This API is mostly used by camera interfaces in embedded platforms.\n 178:\t\n 179:\t#\n 180:\t# DVB Core\n 181:\t#\tOnly enables if one of DTV is selected\n 182:\t#\n 183:\t\n 184:\tconfig DVB_CORE\n" }
81/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 66499 output: 30 thoughts: 10 Thoughts: Okay, here's my attempt at summarizing that thought process, keeping in mind I'm speaking to a fellow expert: Let's Dig into `XFS_FS` Right, time to get to the core. Let's see... the initial directive is vague, but the clear next step is to drill down into `XFS_FS`. This likely means we're dealing with an XFS filesystem-related problem or investigation. So, that's where I'll direct my focus. I need to understand what's relevant to XFS in this context and gather the key data. This could involve looking at specific commands, logs, potential error messages, or kernel dumps, depending on what the bigger picture turns out to be. My immediate goal is to establish a solid baseline for the issue. From there, I can pivot to the relevant area based on what is available.
82/2	2026/09/19 01:41	tool	grepper	0m Args: { "Expression": "config XFS_FS", "PathPrefix": "fs/xfs/" } Results: { "Output": "fs/xfs/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/xfs/Kconfig:2:config XFS_FS\nfs/xfs/Kconfig-3-\ttristate \"XFS filesystem support\"\n" }
83/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 66798 output: 33 thoughts: 10 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue: Checking `GPIO_CDEV` Alright, time to dive in. My initial thought process, as I scan the landscape, is a direct and focused query: "Let's check `GPIO_CDEV`". No need for preamble; I'm assuming that the user understands the context and the problem space we're working within. `GPIO_CDEV` is likely a key piece, and a logical starting point in diagnosing whatever issue is at hand. This is more of a mental checklist item than a fully formed hypothesis, but it represents the first step in a diagnostic process. I am going to check the basics and then look for any oddities.
84/2	2026/09/19 01:41	tool	read-file	0m Args: { "File": "drivers/gpio/Kconfig", "FirstLine": 80, "LineCount": 25 } Results: { "Contents": " 80:\t\t Say Y here if you want to enable the legacy, global GPIO\n 81:\t\t numberspace-based functionalities of the sysfs interface.\n 82:\t\n 83:\tconfig GPIO_CDEV\n 84:\t\tbool \"Character device (/dev/gpiochipN) support\" if EXPERT\n 85:\t\tdefault y\n 86:\t\thelp\n 87:\t\t Say Y here to add the character device /dev/gpiochipN interface\n 88:\t\t for GPIOs. The character device allows userspace to control GPIOs\n 89:\t\t using ioctl() operations.\n 90:\t\n 91:\t\t Only say N if you are sure that the GPIO character device is not\n 92:\t\t required.\n 93:\t\n 94:\t\t If unsure, say Y.\n 95:\t\n 96:\tconfig GPIO_CDEV_V1\n 97:\t\tbool \"Support GPIO ABI Version 1\"\n 98:\t\tdepends on GPIO_CDEV\n 99:\t\thelp\n 100:\t\t Say Y here to support version 1 of the GPIO CDEV ABI.\n 101:\t\n 102:\t\t This ABI version is deprecated.\n 103:\t\t Please use the latest ABI for new developments.\n 104:\t\n" }
85/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 67347 output: 20 thoughts: 1006 Thoughts: Refining the Target Symbol List Okay, let's nail down these focus symbols. The goal is to pinpoint functions that are directly touched by the changes, and are not part of general hotpaths that could introduce too much noise. We need to avoid ubiquitous code like memory allocators or page fault handlers. Ideally, the symbols will be reachable, non-static, and located within the altered `.c` files. So, here are the original candidates: `receive_fd`, `scm_recv_one_fd`, `bpf_token_create`, `bpf_iter_new_fd`, `xfs_open_by_handle`, `handshake_nl_accept_doit`, `media_request_alloc`, `ntsync_obj_get_fd`, `new_userfaultfd`, and `do_eventfd`. But I need to double-check those static functions. `ntsync_obj_get_fd` is static within `ntsync.c`, so that's out. Instead, I should be looking at the direct ioctl entry points within `ntsync.c`, which are `ntsync_char_ioctl`, `ntsync_create_sem`, `ntsync_create_mutex`, and `ntsync_create_event`! That's more specific. Similarly, `new_userfaultfd` isn't ideal. Let's see... `userfaultfd_open`, or `__do_sys_userfaultfd`, or `userfaultfd_dev_ioctl` in `mm/userfaultfd.c` looks better. Ah, and I see now, `do_epoll_create` is static in `fs/eventpoll.c`, and called by `__do_sys_epoll_create1` and `__do_sys_epoll_create`. And `__do_sys_fsmount` and `__do_sys_open_tree_attr` look good too. Plus, I found `kcm_ioctl` in `net/kcm/kcmsock.c`. Okay, taking stock: `receive_fd`, `scm_recv_one_fd`, `bpf_token_create`, `bpf_iter_new_fd`, `xfs_open_by_handle`, `handshake_nl_accept_doit`, and `media_request_alloc` are still the best initial choices, as these directly exercise the `FD_PREPARE` and `fd_publish` logic, plus they're addressable kernel symbols. `kcm_ioctl`, and `__do_sys_open_tree_attr` / `__do_sys_fsmount` also seem very promising. So, let's also verify that we have the correct enable configs. I'm thinking: `BPF_SYSCALL`, `USERFAULTFD`, `NTSYNC`, `AF_KCM`, `XFS_FS`, `NET_HANDSHAKE`, `MEDIA_CONTROLLER`, `MEDIA_SUPPORT`, `GPIO_CDEV`, `GPIO_CDEV_V1`, and `IO_URING_MOCK_FILE`. Now, let's quickly check `NET_HANDSHAKE`. I recall seeing it in `net/Kconfig`, but it seems like it's a hidden config, meaning it's likely pulled in by other configs, like maybe `SUNRPC`. I should check what actually enables it, just to be sure.
86/2	2026/09/19 01:41	tool	grepper	0m Args: { "Expression": "select NET_HANDSHAKE" } Results: { "Output": "drivers/nvme/host/Kconfig=100=config NVME_TCP_TLS\n--\ndrivers/nvme/host/Kconfig-102-\tdepends on NVME_TCP\ndrivers/nvme/host/Kconfig:103:\tselect NET_HANDSHAKE\ndrivers/nvme/host/Kconfig-104-\tselect KEYS\n--\ndrivers/nvme/target/Kconfig=97=config NVME_TARGET_TCP_TLS\n--\ndrivers/nvme/target/Kconfig-99-\tdepends on NVME_TARGET_TCP\ndrivers/nvme/target/Kconfig:100:\tselect NET_HANDSHAKE\ndrivers/nvme/target/Kconfig-101-\tselect TLS\n" }
87/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 69309 output: 29 thoughts: 51 Thoughts: Investigating `SUNRPC` Dependencies Okay, so I'm digging into `SUNRPC` again. Time to see what's relying on it within the `net/` directory. Let's start by looking at what configurations might depend on `SUNRPC` itself. There are a few possibilities that jump out at me - `NVME_TCP_TLS`, `NVME_TARGET_TCP_TLS`, and of course, `SUNRPC` itself. Best to zero in on that last one first, as it's the most obvious starting point for an understanding of its integration. Time to pull up the relevant code and see how `SUNRPC` is being utilized.
88/2	2026/09/19 01:41	tool	grepper	0m Error: no matches Args: { "Expression": "NET_HANDSHAKE", "PathPrefix": "net/sunrpc" } Results: { "error": "no matches" }
89/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 69546 output: 30 thoughts: 47 Thoughts: Decision Time: Network Security for SUNRPC Okay, so I'm trying to figure out the best approach for securing my `SUNRPC` communication. The question is, do I go with `SUNRPC_XPRT_RDMA` or `RPCSEC_GSS_KRB5`? Both have their advantages and disadvantages, depending on the specific environment and requirements. To make an informed decision, I need to understand how these options handle the network handshake. My gut tells me a quick `grepper` search within the `net/sunrpc` directory should give me some insights into how `NET_HANDSHAKE` is implemented in relation to these two choices. Hopefully, I'll find some code examples or documentation that clarifies the connection establishment process for each. This should help me assess which method is more suitable based on the relevant context. I'll need to look for any clues about how this impacts performance, security posture, and compatibility with my existing infrastructure. Let's dig in.
90/2	2026/09/19 01:41	tool	grepper	0m Error: no matches Args: { "Expression": "HANDSHAKE", "PathPrefix": "net/sunrpc/Kconfig" } Results: { "error": "no matches" }
91/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 69847 output: 27 thoughts: 20 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Investigating Network Handshake Configuration Options Alright, I need to get a handle on how network handshake features are configured within this build system. The best first step is always to go straight to the source, the `Kconfig` files. I'm going to leverage `grep` to quickly search through the entire configuration tree for anything related to "NET_HANDSHAKE". This should give me a comprehensive overview of the available options, dependencies, and default settings related to network handshaking, whether it's TCP/IP negotiation, TLS setup, or something more specialized within this particular domain. I'm expecting this will quickly expose the relevant configuration symbols and their associated help text, which will provide a great foundation to understand the implementation and make future decisions about its customization.
92/2	2026/09/19 01:41	tool	grepper	0m Args: { "Expression": "NET_HANDSHAKE", "PathPrefix": "net/" } Results: { "Output": "net/Kconfig=92=source \"net/xdp/Kconfig\"\nnet/Kconfig-93-\nnet/Kconfig:94:config NET_HANDSHAKE\nnet/Kconfig-95-\tbool\n--\nnet/Kconfig-98-\nnet/Kconfig:99:config NET_HANDSHAKE_KUNIT_TEST\nnet/Kconfig-100-\ttristate \"KUnit tests for the handshake upcall mechanism\" if !KUNIT_ALL_TESTS\n--\nnet/Makefile=75=obj-$(CONFIG_MCTP)\t\t+= mctp/\nnet/Makefile:76:obj-$(CONFIG_NET_HANDSHAKE)\t+= handshake/\nnet/Makefile-77-obj-$(CONFIG_NET_SHAPER)\t+= shaper/\n--\nnet/handshake/.kunitconfig=9=CONFIG_SUNRPC=y\nnet/handshake/.kunitconfig:10:CONFIG_NET_HANDSHAKE=y\nnet/handshake/.kunitconfig:11:CONFIG_NET_HANDSHAKE_KUNIT_TEST=y\n--\nnet/handshake/Makefile=11=handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o\nnet/handshake/Makefile-12-\nnet/handshake/Makefile:13:obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o\n" }
93/2	2026/09/19 01:41	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 70427 output: 319 thoughts: 588 Thoughts: My Analysis of Configuration and Reasoning Okay, let's break this down. First, I see that `NET_HANDSHAKE` is selected either by `NVME_TCP_TLS` or `NVME_TARGET_TCP_TLS`. `NET_HANDSHAKE` itself can be configured directly or via `NVME_TCP_TLS`. Got it. Next, I'm checking some dependencies. `IO_URING_MOCK_FILE` relies on both `IO_URING` and `EXPERT`, which makes perfect sense. `NTSYNC` is independent – no dependencies there. `AF_KCM` requires `INET`, which is expected. `GPIO_CDEV` is interesting; it has a prompt controlled by `EXPERT` and depends on `GPIOLIB`. Good to know the potential expert interaction. `MEDIA_CONTROLLER` depends on `MEDIA_SUPPORT`, as I'd anticipate. Now, a quick scan of the `FocusSymbols`. I see a variety of file descriptor related operations, `bpf`, `xfs`, `media`, `handshake` and `ntsync` functions. The list looks comprehensive. Now to the `EnableConfigs`. The key ones are `BPF_SYSCALL`, `USERFAULTFD`, `NTSYNC`, `AF_KCM`, `XFS_FS`, `NET_HANDSHAKE`, and some media and GPIO configs. This seems like a broad selection covering several areas. Finally, the reasoning behind the patch is about RAII cleanup mechanism changes in `include/linux/file.h`. It's a refactoring of `fd_prepare`, `fd_publish`, and `FD_ADD` macros, and the underlying struct layout. This touches file descriptor management, specifically inlining and error reporting. Because of the broad implications, this is high risk with implications for resource management and syscall error paths. Therefore, fuzzing is required to verify the changes prevent memory leaks, double-puts, and regressions across different core subsystems, like VFS, BPF, networking, memory management, and character devices. Excellent. Everything here is aligned and logical. No conflicts or inconsistencies are apparent. I am completely confident to `set-results`.
94/2	2026/09/19 01:41	tool	set-results	0m Args: { "EnableConfigs": [ "BPF_SYSCALL", "USERFAULTFD", "NTSYNC", "AF_KCM", "XFS_FS", "NET_HANDSHAKE", "MEDIA_SUPPORT", "MEDIA_CONTROLLER", "GPIOLIB", "GPIO_CDEV", "GPIO_CDEV_V1" ], "FocusSymbols": [ "receive_fd", "scm_recv_one_fd", "bpf_iter_new_fd", "bpf_token_create", "xfs_open_by_handle", "media_request_alloc", "handshake_nl_accept_doit", "kcm_ioctl", "ntsync_obj_get_fd" ], "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "BPF_SYSCALL", "USERFAULTFD", "NTSYNC", "AF_KCM", "XFS_FS", "NET_HANDSHAKE", "MEDIA_SUPPORT", "MEDIA_CONTROLLER", "GPIOLIB", "GPIO_CDEV", "GPIO_CDEV_V1" ], "FocusSymbols": [ "receive_fd", "scm_recv_one_fd", "bpf_iter_new_fd", "bpf_token_create", "xfs_open_by_handle", "media_request_alloc", "handshake_nl_accept_doit", "kcm_ioctl", "ntsync_obj_get_fd" ], "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.", "WorthFuzzing": true }
95/1	2026/09/19 01:41	action	If	4m Args: { "WorthFuzzing": true } Results: null
96/2	2026/09/19 01:41	agent	kmsan-evaluator	4m Model: core Args: null Results: { "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 58a61ff73c4736b57ba577d0b474d08304b94c83 Author: syz-cluster <triage@syzkaller.com> Date: Sat Sep 19 01:36:27 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c index 2b54afb31529f..5c06f69c9f7f9 100644 --- a/arch/powerpc/platforms/cell/spufs/inode.c +++ b/arch/powerpc/platforms/cell/spufs/inode.c @@ -266,9 +266,9 @@ spufs_mkdir(struct inode dir, struct dentry dentry, unsigned int flags, static int spufs_context_open(const struct path path) { FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; - fd_prepare_file(fdf)->f_op = &spufs_context_fops; + if (fdf->fd < 0) + return fdf->fd; + fdf->file->f_op = &spufs_context_fops; return fd_publish(fdf); } @@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path path) * in error path of _open(). / FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; - fd_prepare_file(fdf)->f_op = &spufs_gang_fops; + if (fdf->fd < 0) + return fdf->fd; + fdf->file->f_op = &spufs_gang_fops; return fd_publish(fdf); } diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 9f3b628d57934..6526ce27ea446 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-linehandle", &linehandle_fileops, lh, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(lh); - handlereq.fd = fd_prepare_fd(fdf); + handlereq.fd = fdf->fd; if (copy_to_user(ip, &handlereq, sizeof(handlereq))) return -EFAULT; @@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-line", &line_fileops, lr, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(lr); - ulr.fd = fd_prepare_fd(fdf); + ulr.fd = fdf->fd; if (copy_to_user(ip, &ulr, sizeof(ulr))) return -EFAULT; @@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device gdev, void __user ip) FD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC, anon_inode_getfile("gpio-event", &lineevent_fileops, le, O_RDONLY \| O_CLOEXEC)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(le); - eventreq.fd = fd_prepare_fd(fdf); + eventreq.fd = fdf->fd; if (copy_to_user(ip, &eventreq, sizeof(eventreq))) return -EFAULT; diff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c index ce65b1160955e..7fa2e858bd082 100644 --- a/drivers/gpu/drm/msm/msm_perfcntr.c +++ b/drivers/gpu/drm/msm/msm_perfcntr.c @@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device dev, void data, struct drm_file f FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("[msm_perfcntrs]", &stream_fops, stream, 0)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; INIT_WORK(&stream->sel_work, sel_worker); kthread_init_work(&stream->sample_work, sample_worker); diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c index 13e77648807c2..e1387f039780b 100644 --- a/drivers/media/mc/mc-request.c +++ b/drivers/media/mc/mc-request.c @@ -316,15 +316,15 @@ int media_request_alloc(struct media_device mdev, int alloc_fd) FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC)); - if (fdf.err) { - ret = fdf.err; + if (fdf->fd < 0) { + ret = fdf->fd; goto err_free_req; } - fd_prepare_file(fdf)->private_data = req; + fdf->file->private_data = req; snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d", - atomic_inc_return(&mdev->request_id), fd_prepare_fd(fdf)); + atomic_inc_return(&mdev->request_id), fdf->fd); atomic_inc(&mdev->num_requests); dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str); diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 4a805919bb0c5..2857ae37d3c81 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj obj) { FD_PREPARE(fdf, O_CLOEXEC, anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR)); - if (fdf.err) - return fdf.err; - obj->file = fd_prepare_file(fdf); + if (fdf->fd < 0) + return fdf->fd; + obj->file = fdf->file; return fd_publish(fdf); } diff --git a/fs/eventfd.c b/fs/eventfd.c index 9d33a02757d52..52426795752ec 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags) FD_PREPARE(fdf, flags, anon_inode_getfile_fmode("[eventfd]", &eventfd_fops, ctx, flags, FMODE_NOWAIT)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL); retain_and_null_ptr(ctx); diff --git a/fs/eventpoll.c b/fs/eventpoll.c index e0c4bf88a8383..f48b829a710f7 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags) FD_PREPARE(fdf, O_RDWR \| (flags & O_CLOEXEC), anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep, O_RDWR \| (flags & O_CLOEXEC))); - if (fdf.err) { + if (fdf->fd < 0) { ep_clear_and_put(ep); - return fdf.err; + return fdf->fd; } - ep->file = fd_prepare_file(fdf); + ep->file = fdf->file; return fd_publish(fdf); } diff --git a/fs/file.c b/fs/file.c index 628ca07dc4b17..2a01b22eb65a1 100644 --- a/fs/file.c +++ b/fs/file.c @@ -1391,17 +1391,17 @@ int receive_fd(struct file file, int __user ufd, unsigned int o_flags) return error; FD_PREPARE(fdf, o_flags, file); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; get_file(file); if (ufd) { - error = put_user(fd_prepare_fd(fdf), ufd); + error = put_user(fdf->fd, ufd); if (error) return error; } - __receive_sock(fd_prepare_file(fdf)); + __receive_sock(fdf->file); return fd_publish(fdf); } EXPORT_SYMBOL_GPL(receive_fd); diff --git a/fs/namespace.c b/fs/namespace.c index 1ecd96c918b33..0f5c00816775b 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0, dentry_open(&new_path, O_PATH, fc->cred)); - if (fdf.err) { + if (fdf->fd < 0) { dissolve_on_fput(new_path.mnt); - return fdf.err; + return fdf->fd; } /* * Attach to an apparent O_PATH fd with a note that we * need to unmount it, not just simply put it. / - fd_prepare_file(fdf)->f_mode \|= FMODE_NEED_UNMOUNT; + fdf->file->f_mode \|= FMODE_NEED_UNMOUNT; return fd_publish(fdf); } @@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user , filename, return -EINVAL; FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; if (uattr) { struct mount_kattr kattr = {}; - struct file file = fd_prepare_file(fdf); + struct file file = fdf->file; int ret; if (flags & OPEN_TREE_CLONE) diff --git a/fs/nsfs.c b/fs/nsfs.c index c3b6ae76594a8..56ea0bb9ef3a3 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -348,8 +348,8 @@ static long ns_ioctl(struct file filp, unsigned int ioctl, return ret; FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred())); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; / * If @uinfo is passed return all information about the * mount namespace as well. diff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c index 0689cade8f74c..303bcff644596 100644 --- a/fs/xfs/xfs_handle.c +++ b/fs/xfs/xfs_handle.c @@ -272,11 +272,11 @@ xfs_open_by_handle( path.mnt = mntget(parfilp->f_path.mnt); FD_PREPARE(fdf, 0, dentry_open(&path, hreq->oflags, cred)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; if (S_ISREG(inode->i_mode)) { - struct file filp = fd_prepare_file(fdf); + struct file filp = fdf->file; filp->f_flags \|= O_NOATIME; filp->f_mode \|= FMODE_NOCMTIME; diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index b1b5698cbf1b6..1fb8058b897d4 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void val) CLASS(name, var)(args...): * declare the variable @var as an instance of the named class * - * CLASS_INIT(name, var, init_expr): - * declare the variable @var as an instance of the named class with - * custom initialization expression. - * * Ex. * * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd) @@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_ class_##_name##_t var __cleanup(class_##_name##_destructor) = \ class_##_name##_constructor -#define CLASS_INIT(_name, _var, _init_expr) \ - class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr) - #define __scoped_class(_name, var, _label, args...) \ for (CLASS(_name, var)(args); ; ({ goto _label; })) \ if (0) { \ diff --git a/include/linux/file.h b/include/linux/file.h index 27484b444d315..41c3c0be10644 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -12,6 +12,7 @@ #include <linux/errno.h> #include <linux/cleanup.h> #include <linux/err.h> +#include <linux/vfsdebug.h> struct file; @@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max; /* * fd_prepare: Combined fd + file allocation cleanup class. - * @err: Error code to indicate if allocation succeeded. - * @__fd: Allocated fd (may not be accessed directly) - * @__file: Allocated struct file pointer (may not be accessed directly) + * @fd: Allocated fd + * @file: Allocated struct file pointer * * Allocates an fd and a file together. On error paths, automatically cleans * up whichever resource was successfully allocated. Allows flexible file * allocation with different functions per usage. * - * Do not use directly. + * Do not declare directly, use FD_PREPARE(). / struct fd_prepare { - s32 err; - s32 __fd; / do not access directly / - struct file __file; /* do not access directly / + int fd; + struct file file; }; -/* Typedef for fd_prepare cleanup guards. / -typedef struct fd_prepare class_fd_prepare_t; - -/ - * Accessors for fd_prepare class members. - * _Generic() is used for zero-cost type safety. - / -#define fd_prepare_fd(_fdf) \ - (_Generic((_fdf), struct fd_prepare: (_fdf).__fd)) - -#define fd_prepare_file(_fdf) \ - (_Generic((_fdf), struct fd_prepare: (_fdf).__file)) - / Do not use directly. / -static inline void class_fd_prepare_destructor(const struct fd_prepare fdf) +static __always_inline void __fd_prepare_cleanup(const struct fd_prepare fdf) { - if (unlikely(fdf->__fd >= 0)) - put_unused_fd(fdf->__fd); - if (unlikely(!IS_ERR_OR_NULL(fdf->__file))) - fput(fdf->__file); + if (unlikely(fdf->fd >= 0)) { + put_unused_fd(fdf->fd); + fput(fdf->file); + } } / Do not use directly. / -static inline int class_fd_prepare_lock_err(const struct fd_prepare fdf) +static __always_inline struct fd_prepare __fd_prepare(int fd, struct file file) { - if (unlikely(fdf->err)) - return fdf->err; - if (unlikely(fdf->__fd < 0)) - return fdf->__fd; - if (unlikely(IS_ERR(fdf->__file))) - return PTR_ERR(fdf->__file); - if (unlikely(!fdf->__file)) - return -ENOMEM; - return 0; + if (fd >= 0 && IS_ERR_OR_NULL(file)) { + int err = file ? PTR_ERR(file) : -ENOMEM; + + put_unused_fd(fd); + fd = err; + file = NULL; + } + return (struct fd_prepare){ .fd = fd, .file = file }; } / - * __FD_PREPARE_INIT - Helper to initialize fd_prepare class. - * @_fd_flags: flags for get_unused_fd_flags() - * @_file_owned: expression that returns struct file * - * - * Returns a struct fd_prepare with fd, file, and err set. - * If fd allocation fails, fd will be negative and err will be set. If - * fd succeeds but file_init_expr fails, file will be ERR_PTR and err - * will be set. The err field is the single source of truth for error - * checking. - / -#define __FD_PREPARE_INIT(_fd_flags, _file_owned) \ - ({ \ - struct fd_prepare fdf = { \ - .__fd = get_unused_fd_flags((_fd_flags)), \ - }; \ - if (likely(fdf.__fd >= 0)) \ - fdf.__file = (_file_owned); \ - fdf.err = ACQUIRE_ERR(fd_prepare, &fdf); \ - fdf; \ - }) - -/ - * FD_PREPARE - Macro to declare and initialize an fd_prepare variable. + * FD_PREPARE - Declare and initialize an fd_prepare instance. * - * Declares and initializes an fd_prepare variable with automatic - * cleanup. No separate scope required - cleanup happens when variable - * goes out of scope. + * This allocates a new fd and only evaluates @_file_owned if the + * allocation succeeded. Cleanup happens when the variable goes out of + * scope and the guard releases whichever of the descriptor and the file + * was allocated. If fd_publish() was called the fd and file are + * published and cleanup becomes a nop. * - * @_fdf: name of struct fd_prepare variable to define + * @_fdf: name of the const struct fd_prepare pointer to define * @_fd_flags: flags for get_unused_fd_flags() * @_file_owned: struct file to take ownership of (can be expression) / +#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned) \ + struct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({ \ + int __fd = get_unused_fd_flags(_fd_flags); \ + __fd_prepare(__fd, __fd < 0 ? NULL : (_file_owned)); \ + }); \ + const struct fd_prepare const _fdf = &_guard + #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \ - CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned)) + __FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned) /* * fd_publish - Publish prepared fd and file to the fd table. - * @_fdf: struct fd_prepare variable + * @fdf: struct fd_prepare pointer defined by FD_PREPARE() / -#define fd_publish(_fdf) \ - ({ \ - struct fd_prepare fdp = &(_fdf); \ - VFS_WARN_ON_ONCE(fdp->err); \ - VFS_WARN_ON_ONCE(fdp->__fd < 0); \ - VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \ - fd_install(fdp->__fd, fdp->__file); \ - retain_and_null_ptr(fdp->__file); \ - take_fd(fdp->__fd); \ - }) +static __always_inline int fd_publish(const struct fd_prepare fdf) +{ + / Callers only get a const view, the guard itself is writable. / + struct fd_prepare guard = (struct fd_prepare )fdf; + + VFS_WARN_ON_ONCE(guard->fd < 0); + fd_install(guard->fd, guard->file); + return take_fd(guard->fd); +} / Do not use directly. / -#define __FD_ADD(_fdf, _fd_flags, _file_owned) \ - ({ \ - FD_PREPARE(_fdf, _fd_flags, _file_owned); \ - s32 ret = _fdf.err; \ - if (likely(!ret)) \ - ret = fd_publish(_fdf); \ - ret; \ +#define __FD_ADD(_fdf, _fd_flags, _file_owned) \ + ({ \ + FD_PREPARE(_fdf, _fd_flags, _file_owned); \ + _fdf->fd < 0 ? _fdf->fd : fd_publish(_fdf); \ }) / diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c index b318ed697998e..9f0b4d850c12f 100644 --- a/io_uring/mock_file.c +++ b/io_uring/mock_file.c @@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd cmd, unsigned int issue_flag FD_PREPARE(fdf, O_RDWR \| O_CLOEXEC, anon_inode_create_getfile("[io_uring_mock]", fops, mf, O_RDWR \| O_CLOEXEC, NULL)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; retain_and_null_ptr(mf); - file = fd_prepare_file(fdf); + file = fdf->file; file->f_mode \|= FMODE_READ \| FMODE_CAN_READ \| FMODE_WRITE \| FMODE_CAN_WRITE \| FMODE_LSEEK; if (mc.flags & IORING_MOCK_CREATE_F_SUPPORT_NOWAIT) file->f_mode \|= FMODE_NOWAIT; - mc.out_fd = fd_prepare_fd(fdf); + mc.out_fd = fdf->fd; if (copy_to_user(uarg, &mc, uarg_size)) return -EFAULT; diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 14a5fdfa04214..5f790d12f72e1 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link link) flags = O_RDONLY \| O_CLOEXEC; FD_PREPARE(fdf, flags, anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; iter_link = container_of(link, struct bpf_iter_link, link); - err = prepare_seq_file(fd_prepare_file(fdf), iter_link); + err = prepare_seq_file(fdf->file, iter_link); if (err) return err; /* Automatic cleanup handles fput / diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c index e85a179523f02..da915a4f972b1 100644 --- a/kernel/bpf/token.c +++ b/kernel/bpf/token.c @@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr attr) FD_PREPARE(fdf, O_CLOEXEC, alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME, O_RDWR, &bpf_token_fops)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; token = kzalloc_obj(token, GFP_USER); if (!token) @@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr attr) return err; get_user_ns(token->userns); - fd_prepare_file(fdf)->private_data = no_free_ptr(token); + fdf->file->private_data = no_free_ptr(token); return fd_publish(fdf); } diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 23fb68fce000e..ea382aedfc90d 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags) anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx, O_RDONLY \| (flags & UFFD_SHARED_FCNTL_FLAGS), NULL)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; /* prevent the mm struct to be freed / mmgrab(ctx->mm); - fd_prepare_file(fdf)->f_mode \|= FMODE_NOWAIT; + fdf->file->f_mode \|= FMODE_NOWAIT; retain_and_null_ptr(ctx); return fd_publish(fdf); } diff --git a/net/core/scm.c b/net/core/scm.c index f0d44ecdb11fc..15c330784a699 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file f, int __user ufd, unsigned int flags, return notrunc ? put_user(error, ufd) : error; FD_PREPARE(fdf, flags, get_file(f)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; - error = put_user(fd_prepare_fd(fdf), ufd); + error = put_user(fdf->fd, ufd); if (error) return error; - __receive_sock(fd_prepare_file(fdf)); + __receive_sock(fdf->file); return fd_publish(fdf); } diff --git a/net/handshake/netlink.c b/net/handshake/netlink.c index 3fd4fef9bab1a..73b8314d9010c 100644 --- a/net/handshake/netlink.c +++ b/net/handshake/netlink.c @@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff skb, struct genl_info info) req = handshake_req_next(hn, class); if (req) { FD_PREPARE(fdf, O_CLOEXEC, req->hr_file); - if (fdf.err) { + if (fdf->fd < 0) { fput(req->hr_file); / drop ref from handshake_req_next() / - err = fdf.err; + err = fdf->fd; goto out_complete; } - err = req->hr_proto->hp_accept(req, info, fd_prepare_fd(fdf)); + err = req->hr_proto->hp_accept(req, info, fdf->fd); if (err) goto out_complete; / Automatic cleanup handles fput / - trace_handshake_cmd_accept(net, req, req->hr_sk, fd_prepare_fd(fdf)); + trace_handshake_cmd_accept(net, req, req->hr_sk, fdf->fd); fd_publish(fdf); return 0; } diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index 71af69d442f21..962ee2c4acd2f 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket sock, unsigned int cmd, unsigned long arg) struct kcm_clone info; FD_PREPARE(fdf, 0, kcm_clone(sock)); - if (fdf.err) - return fdf.err; + if (fdf->fd < 0) + return fdf->fd; - info.fd = fd_prepare_fd(fdf); + info.fd = fdf->fd; if (copy_to_user((void __user *)arg, &info, sizeof(info))) return -EFAULT;
97/3	2026/09/19 01:41	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 10927 output: 30 thoughts: 709 Thoughts: KMSAN Fuzzing Justification: A Deep Dive Okay, so I need to decide if this patch series warrants a dedicated KMSAN fuzzing run, or if the standard KASAN fuzzing is sufficient. Given my expertise, I'm going to take a methodical approach. It looks like this patch touches `FD_PREPARE`, `fd_prepare`, `fd_publish`, and related callers – all pretty critical areas within the kernel's file descriptor handling. Specifically, it seems like the changes are in `include/linux/file.h`. I see there's a struct change. The `fd_prepare` struct has been modified significantly. It looks like the old struct had some 'hidden' fields like `__fd` and `__file` and there's a new cleanup function (`__fd_prepare_cleanup`) as well as some new helper functions: `__fd_prepare`, and macros: `__FD_PREPARE`, `FD_PREPARE`. The structure of the prepare call looks different. I have to understand the context of this to see if the changes are going to impact memory use. I need to understand what `fd_publish` is doing, as it's the interface to how the guard struct is working. And, critically, it calls `take_fd`. This function, along with the cleanup and prepare, are all key to understanding this. The new `fd_publish` function uses this new struct, which means this could have significant impacts. The potential for memory issues is increased by the nature of the operations here. So, I'm going to track down what the `take_fd` function does, and how the cleanup works, because that's what's going to tell me if this patch is a prime candidate for a dedicated KMSAN run. A quick `grepper` search for `take_fd` will be the next step to reveal what's going on behind the scenes here. I need to fully understand how file descriptors are being managed and released in this context to determine the memory safety implications. If this is changing how these are handled, a dedicated KMSAN run might well be justified to catch any potential memory leaks or use-after-free conditions introduced by this refactoring.
98/3	2026/09/19 01:42	tool	grepper	0m Args: { "Expression": "take_fd", "PathPrefix": "include/linux/file.h" } Results: { "Output": "include/linux/file.h=98=DEFINE_FREE(fput, struct file , if (!IS_ERR_OR_NULL(_T)) fput(_T))\n--\ninclude/linux/file.h-100-/\ninclude/linux/file.h:101: * take_fd() will take care to set @fd to -EBADF ensuring that\ninclude/linux/file.h-102- * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it\n--\ninclude/linux/file.h-115- * fd_install(fd, f);\ninclude/linux/file.h:116: * return take_fd(fd);\ninclude/linux/file.h-117- /\ninclude/linux/file.h:118:#define take_fd(fd) __get_and_null(fd, -EBADF)\ninclude/linux/file.h-119-\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare fdf)\n--\ninclude/linux/file.h-202-\tfd_install(guard-\u003efd, guard-\u003efile);\ninclude/linux/file.h:203:\treturn take_fd(guard-\u003efd);\ninclude/linux/file.h-204-}\n" }
99/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 12478 output: 39 thoughts: 603 Thoughts: Analyzing a Potential File Descriptor Leak Okay, so I'm looking at this code and trying to follow the logic. `take_fd(guard->fd)` seems to be setting `guard->fd` to `-EBADF` and returning the previous file descriptor. That `-EBADF` assignment is key. Then, `__fd_prepare_cleanup` comes into play. It checks if `fdf->fd >= 0`. If `guard->fd` was set to `-EBADF` (and therefore `< 0`), the condition is false. That means `put_unused_fd` and `fput` won't be called. That's the cleanup part I need to pay attention to! Now, the changes in the callers look interesting. Before, the code checked for `fdf.err` but the new code checks `fdf->fd < 0`, and the handling differs a bit. It’s checking the error code of `fd` directly. Wait a second...I'm getting a little worried. This is where it gets interesting. I need to dive deeper. Let's look at `kcm_ioctl` in `net/kcm/kcmsock.c`. I see they're using `FD_PREPARE`. Now, the error checking changed from the previous approach where we checked the `err` field. The old way: `if (fdf.err)` to the new: `if (fdf->fd < 0)`. Aha! `info.fd = fdf->fd;` is the key. The previous code had a function called `fd_prepare_fd`, but now, we're simply assigning the value from `fdf->fd`. And that's what's got me concerned. I see they are copying the `info` structure to userspace via `copy_to_user`. Here's the problem. Wait! Does `struct kcm_clone info;` have uninitialized fields? It looks like it does. This could be a potential information leak, especially if `kcm_clone` doesn't fully initialize it! I need to investigate the initialization of `kcm_clone` and surrounding code to make sure it's properly handled, specifically in `net/kcm/kcmsock.c` around line 1580! Time to trace back the flow.
100/3	2026/09/19 01:42	tool	read-file	0m Args: { "File": "net/kcm/kcmsock.c", "FirstLine": 1570, "LineCount": 35 } Results: { "Contents": "1570:\t\t\tstruct kcm_unattach info;\n1571:\t\n1572:\t\t\tif (copy_from_user(\u0026info, (void __user )arg, sizeof(info)))\n1573:\t\t\t\treturn -EFAULT;\n1574:\t\n1575:\t\t\terr = kcm_unattach_ioctl(sock, \u0026info);\n1576:\t\n1577:\t\t\tbreak;\n1578:\t\t}\n1579:\t\tcase SIOCKCMCLONE: {\n1580:\t\t\tstruct kcm_clone info;\n1581:\t\n1582:\t\t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n1583:\t\t\tif (fdf-\u003efd \u003c 0)\n1584:\t\t\t\treturn fdf-\u003efd;\n1585:\t\n1586:\t\t\tinfo.fd = fdf-\u003efd;\n1587:\t\t\tif (copy_to_user((void __user )arg, \u0026info, sizeof(info)))\n1588:\t\t\t\treturn -EFAULT;\n1589:\t\n1590:\t\t\tfd_publish(fdf);\n1591:\t\t\terr = 0;\n1592:\t\t\tbreak;\n1593:\t\t}\n1594:\t\tdefault:\n1595:\t\t\terr = -ENOIOCTLCMD;\n1596:\t\t\tbreak;\n1597:\t\t}\n1598:\t\n1599:\t\treturn err;\n1600:\t}\n1601:\t\n1602:\tstatic void release_mux(struct kcm_mux mux)\n1603:\t{\n1604:\t\tstruct kcm_net knet = mux-\u003eknet;\n" }
101/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14088 output: 21 thoughts: 32 Thoughts: Here's my attempt at summarizing the thought process, as if I were an expert: Diving into `kcm_ioctl` and `kcm_clone` Okay, hold on a minute. The code's talking about a `struct kcm_clone` in `kcm_ioctl`. Right, let's take a quick look at that `struct`. I need to refresh my memory about its contents and how it interacts with the kernel's ioctl implementation for this subsystem. I'll need to understand the data passed through this struct to assess the issue. Gotta make sure it's all making sense in the context of the larger KCM architecture. What are the key fields? How are they being set and used? Okay, let's get to it.
102/3	2026/09/19 01:42	tool	grepper	0m Args: { "Expression": "struct kcm_clone\\b" } Results: { "Output": "Documentation/networking/kcm.rst=128=a KCM socket. This is accomplished by an ioctl on a KCM socket::\n--\nDocumentation/networking/kcm.rst-130- /* From linux/kcm.h /\nDocumentation/networking/kcm.rst:131: struct kcm_clone {\nDocumentation/networking/kcm.rst-132-\tint fd;\n--\nDocumentation/networking/kcm.rst-134-\nDocumentation/networking/kcm.rst:135: struct kcm_clone info;\nDocumentation/networking/kcm.rst-136-\n--\ninclude/uapi/linux/kcm.h=23=struct kcm_unattach {\n--\ninclude/uapi/linux/kcm.h-26-\ninclude/uapi/linux/kcm.h:27:struct kcm_clone {\ninclude/uapi/linux/kcm.h-28-\tint fd;\n--\nnet/kcm/kcmsock.c=1554=static int kcm_ioctl(struct socket sock, unsigned int cmd, unsigned long arg)\n--\nnet/kcm/kcmsock.c-1579-\tcase SIOCKCMCLONE: {\nnet/kcm/kcmsock.c:1580:\t\tstruct kcm_clone info;\nnet/kcm/kcmsock.c-1581-\n" }
103/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14661 output: 40 thoughts: 124 Thoughts: Analyzing a Structure and its Usage Okay, so this `struct kcm_clone` is really bare-bones; it's just an `int fd;`. Seems pretty straightforward, and that `info.fd = fdf->fd;` initialization is essentially copying the file descriptor. No padding issues to worry about, since the struct is just a single integer. I'm noting that this part was already in the code before the patch, which makes the change even less likely to be the root of the problem. Previously, it looked like `info.fd = fd_prepare_fd(fdf)` which was changed to `info.fd = fdf->fd`. But, hold on a second... what about that `drivers/gpio/gpiolib-cdev.c` file? I need to check out the GPIO functions. Let's see... I'll need to look at `linehandle_create`, `linereq_create`, and `lineevent_create`. Let's see if the file descriptor handling logic has changed in any of those. Time to dive in.
104/3	2026/09/19 01:42	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 365, "LineCount": 40 } Results: { "Contents": " 365:\t\t\t} else if (lflags \u0026 GPIOHANDLE_REQUEST_INPUT) {\n 366:\t\t\t\tret = gpiod_direction_input_nonotify(desc);\n 367:\t\t\t\tif (ret)\n 368:\t\t\t\t\treturn ret;\n 369:\t\t\t}\n 370:\t\n 371:\t\t\tgpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);\n 372:\t\n 373:\t\t\tdev_dbg(\u0026gdev-\u003edev, \"registered chardev handle for line %d\\n\",\n 374:\t\t\t\toffset);\n 375:\t\t}\n 376:\t\n 377:\t\tFD_PREPARE(fdf, O_RDONLY \| O_CLOEXEC,\n 378:\t\t\t anon_inode_getfile(\"gpio-linehandle\", \u0026linehandle_fileops,\n 379:\t\t\t\t\t lh, O_RDONLY \| O_CLOEXEC));\n 380:\t\tif (fdf-\u003efd \u003c 0)\n 381:\t\t\treturn fdf-\u003efd;\n 382:\t\tretain_and_null_ptr(lh);\n 383:\t\n 384:\t\thandlereq.fd = fdf-\u003efd;\n 385:\t\tif (copy_to_user(ip, \u0026handlereq, sizeof(handlereq)))\n 386:\t\t\treturn -EFAULT;\n 387:\t\n 388:\t\tfd_publish(fdf);\n 389:\t\n 390:\t\tdev_dbg(\u0026gdev-\u003edev, \"registered chardev handle for %d lines\\n\",\n 391:\t\t\thandlereq.lines);\n 392:\t\n 393:\t\treturn 0;\n 394:\t}\n 395:\t#endif /* CONFIG_GPIO_CDEV_V1 /\n 396:\t\n 397:\t/\n 398:\t struct line - contains the state of a requested line\n 399:\t * @desc: the GPIO descriptor for this line.\n 400:\t * @req: the corresponding line request\n 401:\t * @irq: the interrupt triggered in response to events on this GPIO\n 402:\t * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or\n 403:\t * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied\n 404:\t * @timestamp_ns: cache for the timestamp storing it between hardirq and\n" }
105/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15720 output: 37 thoughts: 79 Thoughts: Okay, let's break this down. Investigating a Potential Inconsistency in GPIOLIB and IO_URING Interfacing Alright, so I'm digging into how these file descriptors are being handled, specifically regarding the communication between the kernel and userspace. My initial thought is focused on `gpiolib-cdev.c`. I see that within the `handlereq`, `ulr`, and `eventreq` functions, the data was previously being copied to userspace using `fd_prepare_fd(fdf)`. Now, I'm noticing a shift; they're using `fdf->fd` directly. This makes me curious. Is this a new development, a refactoring, or perhaps an oversight? My primary concern is this apparent difference in how data is prepared. I need to understand if the change is consistent across the codebase, or if it might be missing elsewhere, potentially introducing a bug or incompatibility. Now, my attention immediately turns to `io_uring/mock_file.c`. This is where I'd expect to see a similar implementation, if there is one. Specifically, I'm looking at `io_create_mock_file`. I'm hoping it's using the same method to copy file descriptors to user space. It should, at the very least, be consistent with the change in gpiolib. If it isn't, I've got a potential inconsistency that warrants further investigation. This difference may allow a method of exploitation.
106/3	2026/09/19 01:42	tool	read-file	0m Args: { "File": "io_uring/mock_file.c", "FirstLine": 250, "LineCount": 35 } Results: { "Contents": " 250:\t\tmf-\u003esize = mc.file_size;\n 251:\t\tmf-\u003erw_delay_ns = mc.rw_delay_ns;\n 252:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_POLL) {\n 253:\t\t\tfops = \u0026io_mock_poll_fops;\n 254:\t\t\tmf-\u003epollable = true;\n 255:\t\t}\n 256:\t\n 257:\t\tFD_PREPARE(fdf, O_RDWR \| O_CLOEXEC,\n 258:\t\t\t anon_inode_create_getfile(\"[io_uring_mock]\", fops, mf,\n 259:\t\t\t\t\t\t O_RDWR \| O_CLOEXEC, NULL));\n 260:\t\tif (fdf-\u003efd \u003c 0)\n 261:\t\t\treturn fdf-\u003efd;\n 262:\t\n 263:\t\tretain_and_null_ptr(mf);\n 264:\t\tfile = fdf-\u003efile;\n 265:\t\tfile-\u003ef_mode \|= FMODE_READ \| FMODE_CAN_READ \| FMODE_WRITE \|\n 266:\t\t\t\tFMODE_CAN_WRITE \| FMODE_LSEEK;\n 267:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)\n 268:\t\t\tfile-\u003ef_mode \|= FMODE_NOWAIT;\n 269:\t\n 270:\t\tmc.out_fd = fdf-\u003efd;\n 271:\t\tif (copy_to_user(uarg, \u0026mc, uarg_size))\n 272:\t\t\treturn -EFAULT;\n 273:\t\n 274:\t\tfd_publish(fdf);\n 275:\t\treturn 0;\n 276:\t}\n 277:\t\n 278:\tstatic int io_probe_mock(struct io_uring_cmd cmd)\n 279:\t{\n 280:\t\tconst struct io_uring_sqe sqe = cmd-\u003esqe;\n 281:\t\tstruct io_uring_mock_probe mp, __user *uarg;\n 282:\t\tsize_t uarg_size;\n 283:\t\n 284:\t\tuarg = u64_to_user_ptr(READ_ONCE(sqe-\u003eaddr));\n" }
107/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16769 output: 37 thoughts: 30 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Debugging a Mock File Creation Function Alright, let's dissect this `io_create_mock_file` function. My initial question is about the variable `mc` within it. Line 220 to 250... that's where the critical assignment or usage must be happening. I need to understand what `mc` represents in this context. Is it a file descriptor, a memory chunk, or something else entirely within this mock file implementation? Knowing its type is crucial to understanding the function's overall behavior. I'll need to carefully examine those lines for variable declarations, assignments, and how `mc` is used subsequently. It could be something straightforward, or it could be a pointer to a struct. Let's dig in and see.
108/3	2026/09/19 01:42	tool	read-file	0m Args: { "File": "io_uring/mock_file.c", "FirstLine": 220, "LineCount": 35 } Results: { "Contents": " 220:\t\t * It's a testing only driver that allows exercising edge cases\n 221:\t\t * that wouldn't be possible to hit otherwise.\n 222:\t\t /\n 223:\t\tadd_taint(TAINT_TEST, LOCKDEP_STILL_OK);\n 224:\t\n 225:\t\tuarg = u64_to_user_ptr(READ_ONCE(sqe-\u003eaddr));\n 226:\t\tuarg_size = READ_ONCE(sqe-\u003elen);\n 227:\t\n 228:\t\tif (sqe-\u003eioprio \|\| sqe-\u003e__pad1 \|\| sqe-\u003eaddr3 \|\| sqe-\u003efile_index)\n 229:\t\t\treturn -EINVAL;\n 230:\t\tif (uarg_size != sizeof(mc))\n 231:\t\t\treturn -EINVAL;\n 232:\t\n 233:\t\tmemset(\u0026mc, 0, sizeof(mc));\n 234:\t\tif (copy_from_user(\u0026mc, uarg, uarg_size))\n 235:\t\t\treturn -EFAULT;\n 236:\t\tif (!mem_is_zero(mc.__resv, sizeof(mc.__resv)))\n 237:\t\t\treturn -EINVAL;\n 238:\t\tif (mc.flags \u0026 ~IO_VALID_CREATE_FLAGS)\n 239:\t\t\treturn -EINVAL;\n 240:\t\tif (mc.file_size \u003e SZ_1G)\n 241:\t\t\treturn -EINVAL;\n 242:\t\tif (mc.rw_delay_ns \u003e NSEC_PER_SEC)\n 243:\t\t\treturn -EINVAL;\n 244:\t\n 245:\t\tmf = kzalloc_obj(mf, GFP_KERNEL_ACCOUNT);\n 246:\t\tif (!mf)\n 247:\t\t\treturn -ENOMEM;\n 248:\t\n 249:\t\tinit_waitqueue_head(\u0026mf-\u003epoll_wq);\n 250:\t\tmf-\u003esize = mc.file_size;\n 251:\t\tmf-\u003erw_delay_ns = mc.rw_delay_ns;\n 252:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_POLL) {\n 253:\t\t\tfops = \u0026io_mock_poll_fops;\n 254:\t\t\tmf-\u003epollable = true;\n" }
109/3	2026/09/19 01:42	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 17625 output: 40 thoughts: 1537 Thoughts: Analyzing File Descriptor Management and Potential Uninitialized Memory Issues Okay, let's break this down systematically. I'm focusing on these changes around file descriptor handling, specifically looking for any potential vulnerabilities related to uninitialized memory. I've got to ensure the file descriptor and file pointer are always handled correctly, with proper cleanup in case of errors. First, I see that `mc` is initialized, copied from user space, and then `mc.out_fd` is set and copied back to user space. This is the starting point to understand the changes in `include/linux/file.h`. I've gone through `include/linux/file.h`, focusing on the core changes. The most important parts seem to be the `FD_PREPARE` macro and the related `__fd_prepare`, `__fd_prepare_cleanup`, and `fd_publish` functions. The key is in understanding how `FD_PREPARE` works: it sets up a `struct fd_prepare` guard (`_guard`) that manages the lifecycle of a file descriptor and file pointer. It uses a statement expression to initialize the `fd` and `file` fields. The critical part is how errors are handled. If `get_unused_fd_flags` or `_file_owned` fail, the code gracefully handles the error, calls `put_unused_fd` on the fd or already returns an error, before the cleanup occurs. After error handling, `__fd_prepare` returns with `fd = -ENOMEM` (for instance) and `file = NULL`. It guarantees that the guard structure is always properly initialized, even in case of an error. `fd_publish` installs the file descriptor into the file descriptor table. The cleanup function is called when the guard goes out of scope and the file descriptor gets cleaned up, even in case of an error. I've carefully considered what happens when the guard is out of scope and `__fd_prepare_cleanup` is called. If the operation fails before `fd_publish` is called (which means `fdf->fd` is negative, which is checked by `VFS_WARN_ON_ONCE` in `fd_publish`), the cleanup function will properly release the allocated file descriptor and the file pointer. If, however, the process continues and `fd_publish` is called, `take_fd` gets the file descriptor which is a valid file descriptor; the return value of `take_fd` is then returned to the user, and the cleanup is skipped. I've examined the `struct fd_prepare`. There's no uninitialized memory in this structure. `fd` is an `int` (4 bytes on a 64-bit architecture) and the padding between `fd` and `file` is inconsequential. Importantly, the `struct fd_prepare` guard is only ever allocated on the kernel stack. It is never exposed to user space directly. Thus, there is no direct risk of leaking uninitialized data to userspace through this structure itself. Only the individual members (`fdf->fd` and `fdf->file`) are ever passed. The `CLASS_INIT` removal in `include/linux/cleanup.h` is just about removing an unused macro, not really relevant. However, I'm not stopping there. I want to make sure the code using `FD_PREPARE` is safe. So, I looked at the call sites within the modified files. The `spufs_context_open` is fine since it immediately assigns the result of the `FD_PREPARE`. But the key is the `drivers/gpio/gpiolib-cdev.c` case and the `linehandle_create` function. I see that the `handlereq.fd` field gets assigned the value `fdf->fd` from the `FD_PREPARE` result and copied to user space. I must make sure that `handlereq` is fully initialized before this copy occurs. That is my next step.
110/3	2026/09/19 01:43	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 300, "LineCount": 40 } Results: { "Contents": " 300:\t\n 301:\tDEFINE_FREE(linehandle_free, struct linehandle_state , if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))\n 302:\t\n 303:\tstatic int linehandle_create(struct gpio_device gdev, void __user ip)\n 304:\t{\n 305:\t\tstruct gpiohandle_request handlereq;\n 306:\t\tstruct linehandle_state lh __free(linehandle_free) = NULL;\n 307:\t\tint i, ret;\n 308:\t\tu32 lflags;\n 309:\t\n 310:\t\tif (copy_from_user(\u0026handlereq, ip, sizeof(handlereq)))\n 311:\t\t\treturn -EFAULT;\n 312:\t\tif ((handlereq.lines == 0) \|\| (handlereq.lines \u003e GPIOHANDLES_MAX))\n 313:\t\t\treturn -EINVAL;\n 314:\t\n 315:\t\tlflags = handlereq.flags;\n 316:\t\n 317:\t\tret = linehandle_validate_flags(lflags);\n 318:\t\tif (ret)\n 319:\t\t\treturn ret;\n 320:\t\n 321:\t\tlh = kzalloc_obj(lh);\n 322:\t\tif (!lh)\n 323:\t\t\treturn -ENOMEM;\n 324:\t\tlh-\u003egdev = gpio_device_get(gdev);\n 325:\t\n 326:\t\tif (handlereq.consumer_label[0] != '\\0') {\n 327:\t\t\t/ label is only initialized if consumer_label is set /\n 328:\t\t\tlh-\u003elabel = kstrndup(handlereq.consumer_label,\n 329:\t\t\t\t\t sizeof(handlereq.consumer_label) - 1,\n 330:\t\t\t\t\t GFP_KERNEL);\n 331:\t\t\tif (!lh-\u003elabel)\n 332:\t\t\t\treturn -ENOMEM;\n 333:\t\t}\n 334:\t\n 335:\t\tlh-\u003enum_descs = handlereq.lines;\n 336:\t\n 337:\t\t/ Request each GPIO */\n 338:\t\tfor (i = 0; i \u003c handlereq.lines; i++) {\n 339:\t\t\tu32 offset = handlereq.lineoffsets[i];\n" }
111/3	2026/09/19 01:43	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 20693 output: 41 thoughts: 93 Thoughts: My Analysis of the Line Handle Creation Process Okay, so I'm looking at `linehandle_create` and the way the request is handled. The core of it seems to be this: `handlereq` is initially copied from user space using `copy_from_user`. My immediate concern, as always, is whether uninitialized memory could be a problem here. But, they've explicitly addressed this. The code then sets `handlereq.fd` to `fdf->fd` and then copies the potentially modified `handlereq` back to user space. Since all the fields of `handlereq` are, in fact, copied from user space initially, I'm satisfied that there shouldn't be any uninitialized byte issues lurking around. That said, I'm not going to stop there. I need to take a look at `linereq_create` and `lineevent_create` as well to make sure there aren't similar vulnerabilities in those. It's good to be thorough.
112/3	2026/09/19 01:43	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 1650, "LineCount": 40 } Results: { "Contents": "1650:\t\tINIT_KFIFO(lr-\u003eevents);\n1651:\t\tlr-\u003eevent_buffer_size = ulr.event_buffer_size;\n1652:\t\tif (lr-\u003eevent_buffer_size == 0)\n1653:\t\t\tlr-\u003eevent_buffer_size = ulr.num_lines * 16;\n1654:\t\telse if (lr-\u003eevent_buffer_size \u003e GPIO_V2_LINES_MAX * 16)\n1655:\t\t\tlr-\u003eevent_buffer_size = GPIO_V2_LINES_MAX * 16;\n1656:\t\n1657:\t\tatomic_set(\u0026lr-\u003eseqno, 0);\n1658:\t\n1659:\t\t/* Request each GPIO /\n1660:\t\tfor (i = 0; i \u003c ulr.num_lines; i++) {\n1661:\t\t\tu32 offset = ulr.offsets[i];\n1662:\t\t\tstruct gpio_desc desc = gpio_device_get_desc(gdev, offset);\n1663:\t\n1664:\t\t\tif (IS_ERR(desc))\n1665:\t\t\t\treturn PTR_ERR(desc);\n1666:\t\n1667:\t\t\tret = gpiod_request_user(desc, lr-\u003elabel);\n1668:\t\t\tif (ret)\n1669:\t\t\t\treturn ret;\n1670:\t\n1671:\t\t\tlr-\u003elines[i].desc = desc;\n1672:\t\t\tflags = gpio_v2_line_config_flags(lc, i);\n1673:\t\t\tgpio_v2_line_config_flags_to_desc_flags(flags, \u0026desc-\u003eflags);\n1674:\t\n1675:\t\t\tret = gpiod_set_transitory(desc, false);\n1676:\t\t\tif (ret \u003c 0)\n1677:\t\t\t\treturn ret;\n1678:\t\n1679:\t\t\tedflags = flags \u0026 GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;\n1680:\t\t\t/\n1681:\t\t\t Lines have to be requested explicitly for input\n1682:\t\t\t * or output, else the line will be treated \"as is\".\n1683:\t\t\t */\n1684:\t\t\tif (flags \u0026 GPIO_V2_LINE_FLAG_OUTPUT) {\n1685:\t\t\t\tint val = gpio_v2_line_config_output_value(lc, i);\n1686:\t\n1687:\t\t\t\tret = gpiod_direction_output_nonotify(desc, val);\n1688:\t\t\t\tif (ret)\n1689:\t\t\t\t\treturn ret;\n" }
113/3	2026/09/19 01:43	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 21730 output: 41 thoughts: 12 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person: Decoding the Data Source: Pinpointing the `url` Origin Alright, so the task at hand is to trace the lineage of `url`. Essentially, I need to figure out the exact point in the code (or data flow, depending on context) where this `url` variable, or data element, was introduced, instantiated, or defined. My initial thought process involves a methodical approach – perhaps a quick search, or maybe a more refined analysis of the surrounding code/data. I am essentially trying to understand the provenance of `url`. Did it come from a configuration file, an external API call, user input, a database lookup, or a hard-coded value within some method? The answer dictates so many downstream implications, I need to understand its root. I'll need to go beyond surface level searching in many cases, and work backwards through its history. This first pass is about locating that initial read, the source.
114/3	2026/09/19 01:43	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 1620, "LineCount": 35 } Results: { "Contents": "1620:\t\t\treturn -EINVAL;\n1621:\t\n1622:\t\tlc = \u0026ulr.config;\n1623:\t\tret = gpio_v2_line_config_validate(lc, ulr.num_lines);\n1624:\t\tif (ret)\n1625:\t\t\treturn ret;\n1626:\t\n1627:\t\tlr = kvzalloc_flex(lr, lines, ulr.num_lines);\n1628:\t\tif (!lr)\n1629:\t\t\treturn -ENOMEM;\n1630:\t\tlr-\u003enum_lines = ulr.num_lines;\n1631:\t\n1632:\t\tlr-\u003egdev = gpio_device_get(gdev);\n1633:\t\n1634:\t\tfor (i = 0; i \u003c ulr.num_lines; i++) {\n1635:\t\t\tlr-\u003elines[i].req = lr;\n1636:\t\t\tWRITE_ONCE(lr-\u003elines[i].sw_debounced, 0);\n1637:\t\t\tINIT_DELAYED_WORK(\u0026lr-\u003elines[i].work, debounce_work_func);\n1638:\t\t}\n1639:\t\n1640:\t\tif (ulr.consumer[0] != '\\0') {\n1641:\t\t\t/ label is only initialized if consumer is set /\n1642:\t\t\tlr-\u003elabel = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,\n1643:\t\t\t\t\t GFP_KERNEL);\n1644:\t\t\tif (!lr-\u003elabel)\n1645:\t\t\t\treturn -ENOMEM;\n1646:\t\t}\n1647:\t\n1648:\t\tmutex_init(\u0026lr-\u003econfig_mutex);\n1649:\t\tinit_waitqueue_head(\u0026lr-\u003ewait);\n1650:\t\tINIT_KFIFO(lr-\u003eevents);\n1651:\t\tlr-\u003eevent_buffer_size = ulr.event_buffer_size;\n1652:\t\tif (lr-\u003eevent_buffer_size == 0)\n1653:\t\t\tlr-\u003eevent_buffer_size = ulr.num_lines 16;\n1654:\t\telse if (lr-\u003eevent_buffer_size \u003e GPIO_V2_LINES_MAX * 16)\n" }
115/3	2026/09/19 01:43	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 22597 output: 41 thoughts: 13 Thoughts: Okay, I'm ready. Here's a summary in the first person, assuming I'm the expert you describe, and starting with the bolded header: Diving Deep into the Data: Lines 1600-1620 Alright, let's see what we're dealing with here, specifically focusing on lines 1600-1620. Given the context of this work, I'm immediately looking for key indicators – the specific parameters and their interactions are where the interesting stuff usually resides. I need to understand what's being measured, what the baseline is, and where the deviation lies. Are we talking about a sudden spike, a gradual trend, or something cyclical? This will influence my interpretation. My initial thought is to cross-reference this segment with the broader dataset and the model’s overall behavior. Is this an isolated anomaly or a part of a larger, potentially significant pattern? I need to ascertain the impact, what other variables may be correlated, and start asking "why?" Why is this happening now? What's the causal link? Furthermore, I am also checking the assumptions that are underlying the section. Are those reasonable? If not, the whole section may need some heavy scrutiny and possible re-modeling. I'm also looking for any obvious flaws in the methodology – data entry errors, mislabeled axes, inappropriate statistical analyses. My years of experience allows me to recognize patterns of concern, and I can quickly start to isolate the most likely explanations. This is where the magic happens – the quick mental correlations and cross-references that come from years of doing this kind of work. Finally, I'm checking to see if these lines have already been analyzed in the past. If the information is new, it will require deep dives to understand the parameters. If the information has been previously discussed, then it will require a re-evaluation to determine if there are any new ideas that should be explored.
116/3	2026/09/19 01:43	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 1600, "LineCount": 25 } Results: { "Contents": "1600:\t};\n1601:\t\n1602:\tDEFINE_FREE(linereq_free, struct linereq , if (!IS_ERR_OR_NULL(_T)) linereq_free(_T))\n1603:\t\n1604:\tstatic int linereq_create(struct gpio_device gdev, void __user ip)\n1605:\t{\n1606:\t\tstruct gpio_v2_line_request ulr;\n1607:\t\tstruct gpio_v2_line_config lc;\n1608:\t\tstruct linereq *lr __free(linereq_free) = NULL;\n1609:\t\tu64 flags, edflags;\n1610:\t\tunsigned int i;\n1611:\t\tint ret;\n1612:\t\n1613:\t\tif (copy_from_user(\u0026ulr, ip, sizeof(ulr)))\n1614:\t\t\treturn -EFAULT;\n1615:\t\n1616:\t\tif ((ulr.num_lines == 0) \|\| (ulr.num_lines \u003e GPIO_V2_LINES_MAX))\n1617:\t\t\treturn -EINVAL;\n1618:\t\n1619:\t\tif (!mem_is_zero(ulr.padding, sizeof(ulr.padding)))\n1620:\t\t\treturn -EINVAL;\n1621:\t\n1622:\t\tlc = \u0026ulr.config;\n1623:\t\tret = gpio_v2_line_config_validate(lc, ulr.num_lines);\n1624:\t\tif (ret)\n" }
117/3	2026/09/19 01:43	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 23479 output: 41 thoughts: 21 Thoughts: My Immediate Observations Okay, so I'm looking at this code and immediately see a pattern. It looks like both `ulr` and `lineevent_create` are being copied from user space. That jumps out at me because it suggests potential security vulnerabilities or inefficiencies, depending on the context. I need to dig deeper to understand why this is happening and what implications it has. Is this a deliberate design choice, or a potential bug? And more importantly, what are the implications for performance and security? I need more information to form a solid conclusion, but this is definitely something to flag and investigate.
118/3	2026/09/19 01:43	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 2040, "LineCount": 30 } Results: { "Contents": "2040:\t\t/* Only one bias flag can be set. /\n2041:\t\tif (((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_DISABLE) \u0026\u0026\n2042:\t\t (lflags \u0026 (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN \|\n2043:\t\t\t\tGPIOHANDLE_REQUEST_BIAS_PULL_UP))) \|\|\n2044:\t\t ((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) \u0026\u0026\n2045:\t\t (lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_UP)))\n2046:\t\t\treturn -EINVAL;\n2047:\t\n2048:\t\tle = kzalloc_obj(le);\n2049:\t\tif (!le)\n2050:\t\t\treturn -ENOMEM;\n2051:\t\tle-\u003egdev = gpio_device_get(gdev);\n2052:\t\n2053:\t\tif (eventreq.consumer_label[0] != '\\0') {\n2054:\t\t\t/* label is only initialized if consumer_label is set */\n2055:\t\t\tle-\u003elabel = kstrndup(eventreq.consumer_label,\n2056:\t\t\t\t\t sizeof(eventreq.consumer_label) - 1,\n2057:\t\t\t\t\t GFP_KERNEL);\n2058:\t\t\tif (!le-\u003elabel)\n2059:\t\t\t\treturn -ENOMEM;\n2060:\t\t}\n2061:\t\n2062:\t\tret = gpiod_request_user(desc, le-\u003elabel);\n2063:\t\tif (ret)\n2064:\t\t\treturn ret;\n2065:\t\tle-\u003edesc = desc;\n2066:\t\tle-\u003eeflags = eflags;\n2067:\t\n2068:\t\tlinehandle_flags_to_desc_flags(lflags, \u0026desc-\u003eflags);\n2069:\t\n" }
119/3	2026/09/19 01:43	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 24169 output: 41 thoughts: 10 Thoughts: Okay, here's the summary, rendered as a first-person account, focusing on the core ideas and assuming a level of expertise: My Initial Assessment of `lineevent_create` Alright, let's dive into this `lineevent_create` function. My initial thought is to immediately consider the context of its use. What kind of line events are we talking about? Network data packets, user inputs, signals, etc.? Understanding that is fundamental. I'm going to quickly look for any clues about the underlying data structure it operates on. Are we dealing with structs, classes, or something more basic? The function's signature will be key. I need to understand its role. Is it a factory, allocating memory and populating a new `lineevent` structure? Or is it more of a configuration and initialization function? Knowing whether it's responsible for memory management is critical, as that dictates my primary concerns regarding potential memory leaks, buffer overflows, or improper resource handling. I'll need to scrutinize how it handles error conditions and what mechanisms are in place for error propagation. Are exceptions being thrown, error codes returned, or is it relying on a global error state? I need to know how resilient it is. The logic flow within the function itself will be paramount. I'm going to quickly map out the typical execution path - what data is required, the steps for initializing the event, any conditional branches, and the final return statement. Are there any resource dependencies – mutexes, semaphores, or other shared resources? These need careful consideration as they are potential points of deadlock or race conditions. I'll be looking for efficient use of any library functions, the handling of data types and casts. Ultimately, I'm expecting this function to be a relatively self-contained unit of functionality, responsible for creating and/or initializing an event representation of some kind of a data stream or stream-related action on a given line. My primary objective is a thorough understanding of its operational details.
120/3	2026/09/19 01:44	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 2020, "LineCount": 25 } Results: { "Contents": "2020:\t\n2021:\t\toffset = eventreq.lineoffset;\n2022:\t\tlflags = eventreq.handleflags;\n2023:\t\teflags = eventreq.eventflags;\n2024:\t\n2025:\t\tdesc = gpio_device_get_desc(gdev, offset);\n2026:\t\tif (IS_ERR(desc))\n2027:\t\t\treturn PTR_ERR(desc);\n2028:\t\n2029:\t\t/* Return an error if a unknown flag is set /\n2030:\t\tif ((lflags \u0026 ~GPIOHANDLE_REQUEST_VALID_FLAGS) \|\|\n2031:\t\t (eflags \u0026 ~GPIOEVENT_REQUEST_VALID_FLAGS))\n2032:\t\t\treturn -EINVAL;\n2033:\t\n2034:\t\t/ This is just wrong: we don't look for events on output lines /\n2035:\t\tif ((lflags \u0026 GPIOHANDLE_REQUEST_OUTPUT) \|\|\n2036:\t\t (lflags \u0026 GPIOHANDLE_REQUEST_OPEN_DRAIN) \|\|\n2037:\t\t (lflags \u0026 GPIOHANDLE_REQUEST_OPEN_SOURCE))\n2038:\t\t\treturn -EINVAL;\n2039:\t\n2040:\t\t/ Only one bias flag can be set. */\n2041:\t\tif (((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_DISABLE) \u0026\u0026\n2042:\t\t (lflags \u0026 (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN \|\n2043:\t\t\t\tGPIOHANDLE_REQUEST_BIAS_PULL_UP))) \|\|\n2044:\t\t ((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) \u0026\u0026\n" }
121/3	2026/09/19 01:44	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25089 output: 41 thoughts: 12 Thoughts: Okay, I'm ready. Here's a summary, in the first person, assuming I'm an expert in the field and considering the prompt's instruction to summarize "before line 2020": My Initial Assessment and Pre-2020 Considerations Alright, before I dive too deep into anything, I need to get my bearings and establish a baseline. Considering the "before line 2020" constraint, I should be focused on the earlier trends, developments, and common assumptions in this domain. What were the prevailing paradigms at that time? What critical breakthroughs had been made or were anticipated? Any ongoing debates or controversies that would have shaped the landscape leading up to that point? I'll be looking for key indicators of that era: the technologies in their infancy, the major players making their moves, and the theoretical underpinnings that were being actively explored. Were there any dominant research programs or industrial initiatives that were setting the agenda? And if so, what were their core tenets and predicted outcomes? Essentially, my focus is understanding the context, so I can see what came before and start making intelligent inferences about possible developments later on. My initial assessment hinges on building this foundation of understanding.
122/3	2026/09/19 01:45	tool	read-file	0m Args: { "File": "drivers/gpio/gpiolib-cdev.c", "FirstLine": 2005, "LineCount": 20 } Results: { "Contents": "2005:\t\n2006:\tstatic int lineevent_create(struct gpio_device gdev, void __user ip)\n2007:\t{\n2008:\t\tstruct gpioevent_request eventreq;\n2009:\t\tstruct lineevent_state le __free(lineevent_free) = NULL;\n2010:\t\tstruct gpio_desc desc;\n2011:\t\tu32 offset;\n2012:\t\tu32 lflags;\n2013:\t\tu32 eflags;\n2014:\t\tint ret;\n2015:\t\tint irq, irqflags = 0;\n2016:\t\tchar *label;\n2017:\t\n2018:\t\tif (copy_from_user(\u0026eventreq, ip, sizeof(eventreq)))\n2019:\t\t\treturn -EFAULT;\n2020:\t\n2021:\t\toffset = eventreq.lineoffset;\n2022:\t\tlflags = eventreq.handleflags;\n2023:\t\teflags = eventreq.eventflags;\n2024:\t\n" }
123/3	2026/09/19 01:45	llm	kmsan-evaluator	1m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25690 output: 393 thoughts: 2089 Thoughts: Analysis of File Descriptor Preparation Refactoring Alright, let's break this down. It seems we've got a patch that's refactoring the `fd_prepare` abstraction, a crucial component for managing file descriptors and their associated resources across the kernel. My initial impression is that this is a simplification of the existing RAII (Resource Acquisition Is Initialization) cleanup mechanism. The intent is to make the code cleaner and more direct, replacing the older `err`, `__fd`, `__file` approach with a more concise `fd` and `file` structure. This should improve readability, which is always a plus. I've gone through the code changes. The original implementation used macros and had an `err` field. The new approach uses direct field access (`fdf->fd`, `fdf->file`) and error checking is now direct, via `fdf->fd < 0`. This is a welcome change. The cleanup strategy, handled by `__fd_prepare_cleanup`, looks sound; it uses the `fd` and `file` from the `fd_prepare` structure to properly release the file descriptor and the associated file. Now, the question becomes: does this refactoring introduce uninitialized memory risks? That's the critical concern, and I've carefully assessed this. I've checked the standard KMSAN criteria: 1. Kernel Data to Userspace: I can see that file descriptors (`fdf->fd`) are being passed to userspace via `put_user` and also in a couple of ioctl structures which I checked closely, such as `gpiolib-cdev.c` and others. But `fdf->fd` is always initialized by `__fd_prepare`. The fields being copied to user space are either integral `int` descriptors or fully initialized structures. No new fields or paddings are exposed. Therefore, no KMSAN risk here. 2. Conditional Logic: The core check is `fdf->fd < 0`, and the code explicitly initializes `fdf->fd`. It's a straightforward check on an initialized variable. No risk of using uninitialized variables in any decision-making path. 3. Complex Data Structures: We aren't creating complex data structures with potentially uninitialized fields that could be read later. 4. Bounds/Length Checks: This is a non-issue. I've thoroughly reviewed the `__fd_prepare_cleanup` function, which handles releasing the resources. The cleanup code is carefully constructed; it checks `fdf->fd >= 0` to make sure we're only attempting to release valid file descriptors and that `_guard` is always initialized by `__fd_prepare`. The potential error paths where either file descriptor acquisition or file creation fails do not leave any uninitialized data anywhere. So, no uninitialized reads occur anywhere in the code. I've also thought about potential edge cases. The bugs this patch is likely to introduce relate to reference counting (double `fput` or leaked `fput` calls), descriptor table issues, or potential use-after-free conditions. Those are not KMSAN issues; those are the domain of KASAN (Kernel Address Sanitizer), refcount debugging tools, and standard kernel warnings, and I'm confident that KASAN will catch any issues. I've concluded that this patch does not introduce or expose any uninitialized memory risks. Dedicated KMSAN fuzzing is not necessary here. Standard KASAN will be sufficient. I'm ready to approve the patch. Let's make sure the reasoning is clear: * The patch simplifies and refactors the `fd_prepare` abstraction. * The structures are fully initialized during preparation. * Any values exposed to user space are either initialized integers or initialized structures. * This is not a KMSAN problem, but KASAN is the right tool here. I've re-checked everything; the analysis is complete.
124/3	2026/09/19 01:46	tool	set-results	0m Args: { "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.", "NeedsKMSAN": false }

Trajectory: (Expand/Collapse All)

Seq

Timestamp

Type

Name

Duration

0/0

2026/09/19 01:36

flow

patch-triage

Args:

null

Results:

{
  "EnableConfigs": [
    "BPF_SYSCALL",
    "USERFAULTFD",
    "NTSYNC",
    "AF_KCM",
    "XFS_FS",
    "NET_HANDSHAKE",
    "MEDIA_SUPPORT",
    "MEDIA_CONTROLLER",
    "GPIOLIB",
    "GPIO_CDEV",
    "GPIO_CDEV_V1"
  ],
  "FocusSymbols": [
    "receive_fd",
    "scm_recv_one_fd",
    "bpf_iter_new_fd",
    "bpf_token_create",
    "xfs_open_by_handle",
    "media_request_alloc",
    "handshake_nl_accept_doit",
    "kcm_ioctl",
    "ntsync_obj_get_fd"
  ],
  "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.",
  "WorthFuzzing": true
}

1/1

2026/09/19 01:36

action

read-patch-diff

Args:

null

Results:

{
  "PatchDiff": "commit 58a61ff73c4736b57ba577d0b474d08304b94c83\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sat Sep 19 01:36:27 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c\nindex 2b54afb31529f..5c06f69c9f7f9 100644\n--- a/arch/powerpc/platforms/cell/spufs/inode.c\n+++ b/arch/powerpc/platforms/cell/spufs/inode.c\n@@ -266,9 +266,9 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,\n static int spufs_context_open(const struct path *path)\n {\n \tFD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tfd_prepare_file(fdf)-\u003ef_op = \u0026spufs_context_fops;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tfdf-\u003efile-\u003ef_op = \u0026spufs_context_fops;\n \treturn fd_publish(fdf);\n }\n \n@@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path *path)\n \t * in error path of *_open().\n \t */\n \tFD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tfd_prepare_file(fdf)-\u003ef_op = \u0026spufs_gang_fops;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tfdf-\u003efile-\u003ef_op = \u0026spufs_gang_fops;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c\nindex 9f3b628d57934..6526ce27ea446 100644\n--- a/drivers/gpio/gpiolib-cdev.c\n+++ b/drivers/gpio/gpiolib-cdev.c\n@@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)\n \tFD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,\n \t\t   anon_inode_getfile(\"gpio-linehandle\", \u0026linehandle_fileops,\n \t\t\t\t      lh, O_RDONLY | O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(lh);\n \n-\thandlereq.fd = fd_prepare_fd(fdf);\n+\thandlereq.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026handlereq, sizeof(handlereq)))\n \t\treturn -EFAULT;\n \n@@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)\n \tFD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,\n \t\t   anon_inode_getfile(\"gpio-line\", \u0026line_fileops, lr,\n \t\t\t\t      O_RDONLY | O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(lr);\n \n-\tulr.fd = fd_prepare_fd(fdf);\n+\tulr.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026ulr, sizeof(ulr)))\n \t\treturn -EFAULT;\n \n@@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)\n \tFD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,\n \t\t   anon_inode_getfile(\"gpio-event\", \u0026lineevent_fileops, le,\n \t\t\t\t      O_RDONLY | O_CLOEXEC));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tretain_and_null_ptr(le);\n \n-\teventreq.fd = fd_prepare_fd(fdf);\n+\teventreq.fd = fdf-\u003efd;\n \tif (copy_to_user(ip, \u0026eventreq, sizeof(eventreq)))\n \t\treturn -EFAULT;\n \ndiff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c\nindex ce65b1160955e..7fa2e858bd082 100644\n--- a/drivers/gpu/drm/msm/msm_perfcntr.c\n+++ b/drivers/gpu/drm/msm/msm_perfcntr.c\n@@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device *dev, void *data, struct drm_file *f\n \n \t\tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t\t   anon_inode_getfile(\"[msm_perfcntrs]\", \u0026stream_fops, stream, 0));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \n \t\tINIT_WORK(\u0026stream-\u003esel_work, sel_worker);\n \t\tkthread_init_work(\u0026stream-\u003esample_work, sample_worker);\ndiff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c\nindex 13e77648807c2..e1387f039780b 100644\n--- a/drivers/media/mc/mc-request.c\n+++ b/drivers/media/mc/mc-request.c\n@@ -316,15 +316,15 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t   anon_inode_getfile(\"request\", \u0026request_fops, NULL,\n \t\t\t\t      O_CLOEXEC));\n-\tif (fdf.err) {\n-\t\tret = fdf.err;\n+\tif (fdf-\u003efd \u003c 0) {\n+\t\tret = fdf-\u003efd;\n \t\tgoto err_free_req;\n \t}\n \n-\tfd_prepare_file(fdf)-\u003eprivate_data = req;\n+\tfdf-\u003efile-\u003eprivate_data = req;\n \n \tsnprintf(req-\u003edebug_str, sizeof(req-\u003edebug_str), \"%u:%d\",\n-\t\t atomic_inc_return(\u0026mdev-\u003erequest_id), fd_prepare_fd(fdf));\n+\t\t atomic_inc_return(\u0026mdev-\u003erequest_id), fdf-\u003efd);\n \tatomic_inc(\u0026mdev-\u003enum_requests);\n \tdev_dbg(mdev-\u003edev, \"request: allocated %s\\n\", req-\u003edebug_str);\n \ndiff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c\nindex 4a805919bb0c5..2857ae37d3c81 100644\n--- a/drivers/misc/ntsync.c\n+++ b/drivers/misc/ntsync.c\n@@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj *obj)\n {\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t   anon_inode_getfile(\"ntsync\", \u0026ntsync_obj_fops, obj, O_RDWR));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n-\tobj-\u003efile = fd_prepare_file(fdf);\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n+\tobj-\u003efile = fdf-\u003efile;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/fs/eventfd.c b/fs/eventfd.c\nindex 9d33a02757d52..52426795752ec 100644\n--- a/fs/eventfd.c\n+++ b/fs/eventfd.c\n@@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags)\n \tFD_PREPARE(fdf, flags,\n \t\t   anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n \t\t\t\t\t    flags, FMODE_NOWAIT));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tctx-\u003eid = ida_alloc(\u0026eventfd_ida, GFP_KERNEL);\n \tretain_and_null_ptr(ctx);\ndiff --git a/fs/eventpoll.c b/fs/eventpoll.c\nindex e0c4bf88a8383..f48b829a710f7 100644\n--- a/fs/eventpoll.c\n+++ b/fs/eventpoll.c\n@@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags)\n \tFD_PREPARE(fdf, O_RDWR | (flags \u0026 O_CLOEXEC),\n \t\t   anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n \t\t\t\t      O_RDWR | (flags \u0026 O_CLOEXEC)));\n-\tif (fdf.err) {\n+\tif (fdf-\u003efd \u003c 0) {\n \t\tep_clear_and_put(ep);\n-\t\treturn fdf.err;\n+\t\treturn fdf-\u003efd;\n \t}\n-\tep-\u003efile = fd_prepare_file(fdf);\n+\tep-\u003efile = fdf-\u003efile;\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/fs/file.c b/fs/file.c\nindex 628ca07dc4b17..2a01b22eb65a1 100644\n--- a/fs/file.c\n+++ b/fs/file.c\n@@ -1391,17 +1391,17 @@ int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)\n \t\treturn error;\n \n \tFD_PREPARE(fdf, o_flags, file);\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \tget_file(file);\n \n \tif (ufd) {\n-\t\terror = put_user(fd_prepare_fd(fdf), ufd);\n+\t\terror = put_user(fdf-\u003efd, ufd);\n \t\tif (error)\n \t\t\treturn error;\n \t}\n \n-\t__receive_sock(fd_prepare_file(fdf));\n+\t__receive_sock(fdf-\u003efile);\n \treturn fd_publish(fdf);\n }\n EXPORT_SYMBOL_GPL(receive_fd);\ndiff --git a/fs/namespace.c b/fs/namespace.c\nindex 1ecd96c918b33..0f5c00816775b 100644\n--- a/fs/namespace.c\n+++ b/fs/namespace.c\n@@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n \n \tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\n \t\t   dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n-\tif (fdf.err) {\n+\tif (fdf-\u003efd \u003c 0) {\n \t\tdissolve_on_fput(new_path.mnt);\n-\t\treturn fdf.err;\n+\t\treturn fdf-\u003efd;\n \t}\n \n \t/*\n \t * Attach to an apparent O_PATH fd with a note that we\n \t * need to unmount it, not just simply put it.\n \t */\n-\tfd_prepare_file(fdf)-\u003ef_mode |= FMODE_NEED_UNMOUNT;\n+\tfdf-\u003efile-\u003ef_mode |= FMODE_NEED_UNMOUNT;\n \treturn fd_publish(fdf);\n }\n \n@@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,\n \t\treturn -EINVAL;\n \n \tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tif (uattr) {\n \t\tstruct mount_kattr kattr = {};\n-\t\tstruct file *file = fd_prepare_file(fdf);\n+\t\tstruct file *file = fdf-\u003efile;\n \t\tint ret;\n \n \t\tif (flags \u0026 OPEN_TREE_CLONE)\ndiff --git a/fs/nsfs.c b/fs/nsfs.c\nindex c3b6ae76594a8..56ea0bb9ef3a3 100644\n--- a/fs/nsfs.c\n+++ b/fs/nsfs.c\n@@ -348,8 +348,8 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,\n \t\t\treturn ret;\n \n \t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \t\t/*\n \t\t * If @uinfo is passed return all information about the\n \t\t * mount namespace as well.\ndiff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c\nindex 0689cade8f74c..303bcff644596 100644\n--- a/fs/xfs/xfs_handle.c\n+++ b/fs/xfs/xfs_handle.c\n@@ -272,11 +272,11 @@ xfs_open_by_handle(\n \tpath.mnt = mntget(parfilp-\u003ef_path.mnt);\n \n \tFD_PREPARE(fdf, 0, dentry_open(\u0026path, hreq-\u003eoflags, cred));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tif (S_ISREG(inode-\u003ei_mode)) {\n-\t\tstruct file *filp = fd_prepare_file(fdf);\n+\t\tstruct file *filp = fdf-\u003efile;\n \n \t\tfilp-\u003ef_flags |= O_NOATIME;\n \t\tfilp-\u003ef_mode |= FMODE_NOCMTIME;\ndiff --git a/include/linux/cleanup.h b/include/linux/cleanup.h\nindex b1b5698cbf1b6..1fb8058b897d4 100644\n--- a/include/linux/cleanup.h\n+++ b/include/linux/cleanup.h\n@@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void *val)\n  * CLASS(name, var)(args...):\n  *\tdeclare the variable @var as an instance of the named class\n  *\n- * CLASS_INIT(name, var, init_expr):\n- *\tdeclare the variable @var as an instance of the named class with\n- *\tcustom initialization expression.\n- *\n  * Ex.\n  *\n  * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd)\n@@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_\n \tclass_##_name##_t var __cleanup(class_##_name##_destructor) =\t\\\n \t\tclass_##_name##_constructor\n \n-#define CLASS_INIT(_name, _var, _init_expr)                             \\\n-        class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr)\n-\n #define __scoped_class(_name, var, _label, args...)        \\\n \tfor (CLASS(_name, var)(args); ; ({ goto _label; })) \\\n \t\tif (0) {                                   \\\ndiff --git a/include/linux/file.h b/include/linux/file.h\nindex 27484b444d315..41c3c0be10644 100644\n--- a/include/linux/file.h\n+++ b/include/linux/file.h\n@@ -12,6 +12,7 @@\n #include \u003clinux/errno.h\u003e\n #include \u003clinux/cleanup.h\u003e\n #include \u003clinux/err.h\u003e\n+#include \u003clinux/vfsdebug.h\u003e\n \n struct file;\n \n@@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;\n \n /*\n  * fd_prepare: Combined fd + file allocation cleanup class.\n- * @err: Error code to indicate if allocation succeeded.\n- * @__fd: Allocated fd (may not be accessed directly)\n- * @__file: Allocated struct file pointer (may not be accessed directly)\n+ * @fd: Allocated fd\n+ * @file: Allocated struct file pointer\n  *\n  * Allocates an fd and a file together. On error paths, automatically cleans\n  * up whichever resource was successfully allocated. Allows flexible file\n  * allocation with different functions per usage.\n  *\n- * Do not use directly.\n+ * Do not declare directly, use FD_PREPARE().\n  */\n struct fd_prepare {\n-\ts32 err;\n-\ts32 __fd; /* do not access directly */\n-\tstruct file *__file; /* do not access directly */\n+\tint fd;\n+\tstruct file *file;\n };\n \n-/* Typedef for fd_prepare cleanup guards. */\n-typedef struct fd_prepare class_fd_prepare_t;\n-\n-/*\n- * Accessors for fd_prepare class members.\n- * _Generic() is used for zero-cost type safety.\n- */\n-#define fd_prepare_fd(_fdf) \\\n-\t(_Generic((_fdf), struct fd_prepare: (_fdf).__fd))\n-\n-#define fd_prepare_file(_fdf) \\\n-\t(_Generic((_fdf), struct fd_prepare: (_fdf).__file))\n-\n /* Do not use directly. */\n-static inline void class_fd_prepare_destructor(const struct fd_prepare *fdf)\n+static __always_inline void __fd_prepare_cleanup(const struct fd_prepare *fdf)\n {\n-\tif (unlikely(fdf-\u003e__fd \u003e= 0))\n-\t\tput_unused_fd(fdf-\u003e__fd);\n-\tif (unlikely(!IS_ERR_OR_NULL(fdf-\u003e__file)))\n-\t\tfput(fdf-\u003e__file);\n+\tif (unlikely(fdf-\u003efd \u003e= 0)) {\n+\t\tput_unused_fd(fdf-\u003efd);\n+\t\tfput(fdf-\u003efile);\n+\t}\n }\n \n /* Do not use directly. */\n-static inline int class_fd_prepare_lock_err(const struct fd_prepare *fdf)\n+static __always_inline struct fd_prepare __fd_prepare(int fd, struct file *file)\n {\n-\tif (unlikely(fdf-\u003eerr))\n-\t\treturn fdf-\u003eerr;\n-\tif (unlikely(fdf-\u003e__fd \u003c 0))\n-\t\treturn fdf-\u003e__fd;\n-\tif (unlikely(IS_ERR(fdf-\u003e__file)))\n-\t\treturn PTR_ERR(fdf-\u003e__file);\n-\tif (unlikely(!fdf-\u003e__file))\n-\t\treturn -ENOMEM;\n-\treturn 0;\n+\tif (fd \u003e= 0 \u0026\u0026 IS_ERR_OR_NULL(file)) {\n+\t\tint err = file ? PTR_ERR(file) : -ENOMEM;\n+\n+\t\tput_unused_fd(fd);\n+\t\tfd = err;\n+\t\tfile = NULL;\n+\t}\n+\treturn (struct fd_prepare){ .fd = fd, .file = file };\n }\n \n /*\n- * __FD_PREPARE_INIT - Helper to initialize fd_prepare class.\n- * @_fd_flags: flags for get_unused_fd_flags()\n- * @_file_owned: expression that returns struct file *\n- *\n- * Returns a struct fd_prepare with fd, file, and err set.\n- * If fd allocation fails, fd will be negative and err will be set. If\n- * fd succeeds but file_init_expr fails, file will be ERR_PTR and err\n- * will be set. The err field is the single source of truth for error\n- * checking.\n- */\n-#define __FD_PREPARE_INIT(_fd_flags, _file_owned)                 \\\n-\t({                                                        \\\n-\t\tstruct fd_prepare fdf = {                         \\\n-\t\t\t.__fd = get_unused_fd_flags((_fd_flags)), \\\n-\t\t};                                                \\\n-\t\tif (likely(fdf.__fd \u003e= 0))                        \\\n-\t\t\tfdf.__file = (_file_owned);               \\\n-\t\tfdf.err = ACQUIRE_ERR(fd_prepare, \u0026fdf);          \\\n-\t\tfdf;                                              \\\n-\t})\n-\n-/*\n- * FD_PREPARE - Macro to declare and initialize an fd_prepare variable.\n+ * FD_PREPARE - Declare and initialize an fd_prepare instance.\n  *\n- * Declares and initializes an fd_prepare variable with automatic\n- * cleanup. No separate scope required - cleanup happens when variable\n- * goes out of scope.\n+ * This allocates a new fd and only evaluates @_file_owned if the\n+ * allocation succeeded. Cleanup happens when the variable goes out of\n+ * scope and the guard releases whichever of the descriptor and the file\n+ * was allocated. If fd_publish() was called the fd and file are\n+ * published and cleanup becomes a nop.\n  *\n- * @_fdf: name of struct fd_prepare variable to define\n+ * @_fdf: name of the const struct fd_prepare pointer to define\n  * @_fd_flags: flags for get_unused_fd_flags()\n  * @_file_owned: struct file to take ownership of (can be expression)\n  */\n+#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)\t\t\\\n+\tstruct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({\t\\\n+\t\tint __fd = get_unused_fd_flags(_fd_flags);\t\t\\\n+\t\t__fd_prepare(__fd, __fd \u003c 0 ? NULL : (_file_owned));\t\\\n+\t});\t\t\t\t\t\t\t\t\\\n+\tconst struct fd_prepare *const _fdf = \u0026_guard\n+\n #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \\\n-\tCLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))\n+\t__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)\n \n /*\n  * fd_publish - Publish prepared fd and file to the fd table.\n- * @_fdf: struct fd_prepare variable\n+ * @fdf: struct fd_prepare pointer defined by FD_PREPARE()\n  */\n-#define fd_publish(_fdf)                                       \\\n-\t({                                                     \\\n-\t\tstruct fd_prepare *fdp = \u0026(_fdf);              \\\n-\t\tVFS_WARN_ON_ONCE(fdp-\u003eerr);                    \\\n-\t\tVFS_WARN_ON_ONCE(fdp-\u003e__fd \u003c 0);               \\\n-\t\tVFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp-\u003e__file)); \\\n-\t\tfd_install(fdp-\u003e__fd, fdp-\u003e__file);            \\\n-\t\tretain_and_null_ptr(fdp-\u003e__file);              \\\n-\t\ttake_fd(fdp-\u003e__fd);                            \\\n-\t})\n+static __always_inline int fd_publish(const struct fd_prepare *fdf)\n+{\n+\t/* Callers only get a const view, the guard itself is writable. */\n+\tstruct fd_prepare *guard = (struct fd_prepare *)fdf;\n+\n+\tVFS_WARN_ON_ONCE(guard-\u003efd \u003c 0);\n+\tfd_install(guard-\u003efd, guard-\u003efile);\n+\treturn take_fd(guard-\u003efd);\n+}\n \n /* Do not use directly. */\n-#define __FD_ADD(_fdf, _fd_flags, _file_owned)            \\\n-\t({                                                \\\n-\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned); \\\n-\t\ts32 ret = _fdf.err;                       \\\n-\t\tif (likely(!ret))                         \\\n-\t\t\tret = fd_publish(_fdf);           \\\n-\t\tret;                                      \\\n+#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\n+\t({\t\t\t\t\t\t\t\\\n+\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned);\t\\\n+\t\t_fdf-\u003efd \u003c 0 ? _fdf-\u003efd : fd_publish(_fdf);\t\\\n \t})\n \n /*\ndiff --git a/io_uring/mock_file.c b/io_uring/mock_file.c\nindex b318ed697998e..9f0b4d850c12f 100644\n--- a/io_uring/mock_file.c\n+++ b/io_uring/mock_file.c\n@@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag\n \tFD_PREPARE(fdf, O_RDWR | O_CLOEXEC,\n \t\t   anon_inode_create_getfile(\"[io_uring_mock]\", fops, mf,\n \t\t\t\t\t     O_RDWR | O_CLOEXEC, NULL));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \tretain_and_null_ptr(mf);\n-\tfile = fd_prepare_file(fdf);\n+\tfile = fdf-\u003efile;\n \tfile-\u003ef_mode |= FMODE_READ | FMODE_CAN_READ | FMODE_WRITE |\n \t\t\tFMODE_CAN_WRITE | FMODE_LSEEK;\n \tif (mc.flags \u0026 IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)\n \t\tfile-\u003ef_mode |= FMODE_NOWAIT;\n \n-\tmc.out_fd = fd_prepare_fd(fdf);\n+\tmc.out_fd = fdf-\u003efd;\n \tif (copy_to_user(uarg, \u0026mc, uarg_size))\n \t\treturn -EFAULT;\n \ndiff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c\nindex 14a5fdfa04214..5f790d12f72e1 100644\n--- a/kernel/bpf/bpf_iter.c\n+++ b/kernel/bpf/bpf_iter.c\n@@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link *link)\n \tflags = O_RDONLY | O_CLOEXEC;\n \n \tFD_PREPARE(fdf, flags, anon_inode_getfile(\"bpf_iter\", \u0026bpf_iter_fops, NULL, flags));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \titer_link = container_of(link, struct bpf_iter_link, link);\n-\terr = prepare_seq_file(fd_prepare_file(fdf), iter_link);\n+\terr = prepare_seq_file(fdf-\u003efile, iter_link);\n \tif (err)\n \t\treturn err; /* Automatic cleanup handles fput */\n \ndiff --git a/kernel/bpf/token.c b/kernel/bpf/token.c\nindex e85a179523f02..da915a4f972b1 100644\n--- a/kernel/bpf/token.c\n+++ b/kernel/bpf/token.c\n@@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr *attr)\n \tFD_PREPARE(fdf, O_CLOEXEC,\n \t\t   alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME,\n \t\t\t\t     O_RDWR, \u0026bpf_token_fops));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \ttoken = kzalloc_obj(*token, GFP_USER);\n \tif (!token)\n@@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr *attr)\n \t\treturn err;\n \n \tget_user_ns(token-\u003euserns);\n-\tfd_prepare_file(fdf)-\u003eprivate_data = no_free_ptr(token);\n+\tfdf-\u003efile-\u003eprivate_data = no_free_ptr(token);\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/mm/userfaultfd.c b/mm/userfaultfd.c\nindex 23fb68fce000e..ea382aedfc90d 100644\n--- a/mm/userfaultfd.c\n+++ b/mm/userfaultfd.c\n@@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags)\n \t\t   anon_inode_create_getfile(\"[userfaultfd]\", \u0026userfaultfd_fops, ctx,\n \t\t\t\t\t     O_RDONLY | (flags \u0026 UFFD_SHARED_FCNTL_FLAGS),\n \t\t\t\t\t     NULL));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n \t/* prevent the mm struct to be freed */\n \tmmgrab(ctx-\u003emm);\n-\tfd_prepare_file(fdf)-\u003ef_mode |= FMODE_NOWAIT;\n+\tfdf-\u003efile-\u003ef_mode |= FMODE_NOWAIT;\n \tretain_and_null_ptr(ctx);\n \treturn fd_publish(fdf);\n }\ndiff --git a/net/core/scm.c b/net/core/scm.c\nindex f0d44ecdb11fc..15c330784a699 100644\n--- a/net/core/scm.c\n+++ b/net/core/scm.c\n@@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file *f, int __user *ufd, unsigned int flags,\n \t\treturn notrunc ? put_user(error, ufd) : error;\n \n \tFD_PREPARE(fdf, flags, get_file(f));\n-\tif (fdf.err)\n-\t\treturn fdf.err;\n+\tif (fdf-\u003efd \u003c 0)\n+\t\treturn fdf-\u003efd;\n \n-\terror = put_user(fd_prepare_fd(fdf), ufd);\n+\terror = put_user(fdf-\u003efd, ufd);\n \tif (error)\n \t\treturn error;\n \n-\t__receive_sock(fd_prepare_file(fdf));\n+\t__receive_sock(fdf-\u003efile);\n \treturn fd_publish(fdf);\n }\n \ndiff --git a/net/handshake/netlink.c b/net/handshake/netlink.c\nindex 3fd4fef9bab1a..73b8314d9010c 100644\n--- a/net/handshake/netlink.c\n+++ b/net/handshake/netlink.c\n@@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)\n \treq = handshake_req_next(hn, class);\n \tif (req) {\n \t\tFD_PREPARE(fdf, O_CLOEXEC, req-\u003ehr_file);\n-\t\tif (fdf.err) {\n+\t\tif (fdf-\u003efd \u003c 0) {\n \t\t\tfput(req-\u003ehr_file); /* drop ref from handshake_req_next() */\n-\t\t\terr = fdf.err;\n+\t\t\terr = fdf-\u003efd;\n \t\t\tgoto out_complete;\n \t\t}\n \n-\t\terr = req-\u003ehr_proto-\u003ehp_accept(req, info, fd_prepare_fd(fdf));\n+\t\terr = req-\u003ehr_proto-\u003ehp_accept(req, info, fdf-\u003efd);\n \t\tif (err)\n \t\t\tgoto out_complete; /* Automatic cleanup handles fput */\n \n-\t\ttrace_handshake_cmd_accept(net, req, req-\u003ehr_sk, fd_prepare_fd(fdf));\n+\t\ttrace_handshake_cmd_accept(net, req, req-\u003ehr_sk, fdf-\u003efd);\n \t\tfd_publish(fdf);\n \t\treturn 0;\n \t}\ndiff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c\nindex 71af69d442f21..962ee2c4acd2f 100644\n--- a/net/kcm/kcmsock.c\n+++ b/net/kcm/kcmsock.c\n@@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)\n \t\tstruct kcm_clone info;\n \n \t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n-\t\tif (fdf.err)\n-\t\t\treturn fdf.err;\n+\t\tif (fdf-\u003efd \u003c 0)\n+\t\t\treturn fdf-\u003efd;\n \n-\t\tinfo.fd = fd_prepare_fd(fdf);\n+\t\tinfo.fd = fdf-\u003efd;\n \t\tif (copy_to_user((void __user *)arg, \u0026info, sizeof(info)))\n \t\t\treturn -EFAULT;\n \n"
}

2/1

2026/09/19 01:36

agent

patch-evaluator

Model:

core

Args:

null

Results:

{
  "EnableConfigs": [
    "BPF_SYSCALL",
    "USERFAULTFD",
    "NTSYNC",
    "AF_KCM",
    "XFS_FS",
    "NET_HANDSHAKE",
    "MEDIA_SUPPORT",
    "MEDIA_CONTROLLER",
    "GPIOLIB",
    "GPIO_CDEV",
    "GPIO_CDEV_V1"
  ],
  "FocusSymbols": [
    "receive_fd",
    "scm_recv_one_fd",
    "bpf_iter_new_fd",
    "bpf_token_create",
    "xfs_open_by_handle",
    "media_request_alloc",
    "handshake_nl_accept_doit",
    "kcm_ioctl",
    "ntsync_obj_get_fd"
  ],
  "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.",
  "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 58a61ff73c4736b57ba577d0b474d08304b94c83
Author: syz-cluster <triage@syzkaller.com>
Date:   Sat Sep 19 01:36:27 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 2b54afb31529f..5c06f69c9f7f9 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -266,9 +266,9 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
 static int spufs_context_open(const struct path *path)
 {
 	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	if (fdf.err)
-		return fdf.err;
-	fd_prepare_file(fdf)->f_op = &spufs_context_fops;
+	if (fdf->fd < 0)
+		return fdf->fd;
+	fdf->file->f_op = &spufs_context_fops;
 	return fd_publish(fdf);
 }
 
@@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path *path)
 	 * in error path of *_open().
 	 */
 	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	if (fdf.err)
-		return fdf.err;
-	fd_prepare_file(fdf)->f_op = &spufs_gang_fops;
+	if (fdf->fd < 0)
+		return fdf->fd;
+	fdf->file->f_op = &spufs_gang_fops;
 	return fd_publish(fdf);
 }
 
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 9f3b628d57934..6526ce27ea446 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-linehandle", &linehandle_fileops,
 				      lh, O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(lh);
 
-	handlereq.fd = fd_prepare_fd(fdf);
+	handlereq.fd = fdf->fd;
 	if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
 		return -EFAULT;
 
@@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-line", &line_fileops, lr,
 				      O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(lr);
 
-	ulr.fd = fd_prepare_fd(fdf);
+	ulr.fd = fdf->fd;
 	if (copy_to_user(ip, &ulr, sizeof(ulr)))
 		return -EFAULT;
 
@@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-event", &lineevent_fileops, le,
 				      O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(le);
 
-	eventreq.fd = fd_prepare_fd(fdf);
+	eventreq.fd = fdf->fd;
 	if (copy_to_user(ip, &eventreq, sizeof(eventreq)))
 		return -EFAULT;
 
diff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c
index ce65b1160955e..7fa2e858bd082 100644
--- a/drivers/gpu/drm/msm/msm_perfcntr.c
+++ b/drivers/gpu/drm/msm/msm_perfcntr.c
@@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device *dev, void *data, struct drm_file *f
 
 		FD_PREPARE(fdf, O_CLOEXEC,
 			   anon_inode_getfile("[msm_perfcntrs]", &stream_fops, stream, 0));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 
 		INIT_WORK(&stream->sel_work, sel_worker);
 		kthread_init_work(&stream->sample_work, sample_worker);
diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c
index 13e77648807c2..e1387f039780b 100644
--- a/drivers/media/mc/mc-request.c
+++ b/drivers/media/mc/mc-request.c
@@ -316,15 +316,15 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   anon_inode_getfile("request", &request_fops, NULL,
 				      O_CLOEXEC));
-	if (fdf.err) {
-		ret = fdf.err;
+	if (fdf->fd < 0) {
+		ret = fdf->fd;
 		goto err_free_req;
 	}
 
-	fd_prepare_file(fdf)->private_data = req;
+	fdf->file->private_data = req;
 
 	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
-		 atomic_inc_return(&mdev->request_id), fd_prepare_fd(fdf));
+		 atomic_inc_return(&mdev->request_id), fdf->fd);
 	atomic_inc(&mdev->num_requests);
 	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
 
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 4a805919bb0c5..2857ae37d3c81 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj *obj)
 {
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR));
-	if (fdf.err)
-		return fdf.err;
-	obj->file = fd_prepare_file(fdf);
+	if (fdf->fd < 0)
+		return fdf->fd;
+	obj->file = fdf->file;
 	return fd_publish(fdf);
 }
 
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 9d33a02757d52..52426795752ec 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags)
 	FD_PREPARE(fdf, flags,
 		   anon_inode_getfile_fmode("[eventfd]", &eventfd_fops, ctx,
 					    flags, FMODE_NOWAIT));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL);
 	retain_and_null_ptr(ctx);
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index e0c4bf88a8383..f48b829a710f7 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags)
 	FD_PREPARE(fdf, O_RDWR | (flags & O_CLOEXEC),
 		   anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
 				      O_RDWR | (flags & O_CLOEXEC)));
-	if (fdf.err) {
+	if (fdf->fd < 0) {
 		ep_clear_and_put(ep);
-		return fdf.err;
+		return fdf->fd;
 	}
-	ep->file = fd_prepare_file(fdf);
+	ep->file = fdf->file;
 	return fd_publish(fdf);
 }
 
diff --git a/fs/file.c b/fs/file.c
index 628ca07dc4b17..2a01b22eb65a1 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -1391,17 +1391,17 @@ int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
 		return error;
 
 	FD_PREPARE(fdf, o_flags, file);
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	get_file(file);
 
 	if (ufd) {
-		error = put_user(fd_prepare_fd(fdf), ufd);
+		error = put_user(fdf->fd, ufd);
 		if (error)
 			return error;
 	}
 
-	__receive_sock(fd_prepare_file(fdf));
+	__receive_sock(fdf->file);
 	return fd_publish(fdf);
 }
 EXPORT_SYMBOL_GPL(receive_fd);
diff --git a/fs/namespace.c b/fs/namespace.c
index 1ecd96c918b33..0f5c00816775b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 
 	FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,
 		   dentry_open(&new_path, O_PATH, fc->cred));
-	if (fdf.err) {
+	if (fdf->fd < 0) {
 		dissolve_on_fput(new_path.mnt);
-		return fdf.err;
+		return fdf->fd;
 	}
 
 	/*
 	 * Attach to an apparent O_PATH fd with a note that we
 	 * need to unmount it, not just simply put it.
 	 */
-	fd_prepare_file(fdf)->f_mode |= FMODE_NEED_UNMOUNT;
+	fdf->file->f_mode |= FMODE_NEED_UNMOUNT;
 	return fd_publish(fdf);
 }
 
@@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,
 		return -EINVAL;
 
 	FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	if (uattr) {
 		struct mount_kattr kattr = {};
-		struct file *file = fd_prepare_file(fdf);
+		struct file *file = fdf->file;
 		int ret;
 
 		if (flags & OPEN_TREE_CLONE)
diff --git a/fs/nsfs.c b/fs/nsfs.c
index c3b6ae76594a8..56ea0bb9ef3a3 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -348,8 +348,8 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 			return ret;
 
 		FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 		/*
 		 * If @uinfo is passed return all information about the
 		 * mount namespace as well.
diff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c
index 0689cade8f74c..303bcff644596 100644
--- a/fs/xfs/xfs_handle.c
+++ b/fs/xfs/xfs_handle.c
@@ -272,11 +272,11 @@ xfs_open_by_handle(
 	path.mnt = mntget(parfilp->f_path.mnt);
 
 	FD_PREPARE(fdf, 0, dentry_open(&path, hreq->oflags, cred));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	if (S_ISREG(inode->i_mode)) {
-		struct file *filp = fd_prepare_file(fdf);
+		struct file *filp = fdf->file;
 
 		filp->f_flags |= O_NOATIME;
 		filp->f_mode |= FMODE_NOCMTIME;
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index b1b5698cbf1b6..1fb8058b897d4 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void *val)
  * CLASS(name, var)(args...):
  *	declare the variable @var as an instance of the named class
  *
- * CLASS_INIT(name, var, init_expr):
- *	declare the variable @var as an instance of the named class with
- *	custom initialization expression.
- *
  * Ex.
  *
  * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd)
@@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_
 	class_##_name##_t var __cleanup(class_##_name##_destructor) =	\
 		class_##_name##_constructor
 
-#define CLASS_INIT(_name, _var, _init_expr)                             \
-        class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr)
-
 #define __scoped_class(_name, var, _label, args...)        \
 	for (CLASS(_name, var)(args); ; ({ goto _label; })) \
 		if (0) {                                   \
diff --git a/include/linux/file.h b/include/linux/file.h
index 27484b444d315..41c3c0be10644 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -12,6 +12,7 @@
 #include <linux/errno.h>
 #include <linux/cleanup.h>
 #include <linux/err.h>
+#include <linux/vfsdebug.h>
 
 struct file;
 
@@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
 
 /*
  * fd_prepare: Combined fd + file allocation cleanup class.
- * @err: Error code to indicate if allocation succeeded.
- * @__fd: Allocated fd (may not be accessed directly)
- * @__file: Allocated struct file pointer (may not be accessed directly)
+ * @fd: Allocated fd
+ * @file: Allocated struct file pointer
  *
  * Allocates an fd and a file together. On error paths, automatically cleans
  * up whichever resource was successfully allocated. Allows flexible file
  * allocation with different functions per usage.
  *
- * Do not use directly.
+ * Do not declare directly, use FD_PREPARE().
  */
 struct fd_prepare {
-	s32 err;
-	s32 __fd; /* do not access directly */
-	struct file *__file; /* do not access directly */
+	int fd;
+	struct file *file;
 };
 
-/* Typedef for fd_prepare cleanup guards. */
-typedef struct fd_prepare class_fd_prepare_t;
-
-/*
- * Accessors for fd_prepare class members.
- * _Generic() is used for zero-cost type safety.
- */
-#define fd_prepare_fd(_fdf) \
-	(_Generic((_fdf), struct fd_prepare: (_fdf).__fd))
-
-#define fd_prepare_file(_fdf) \
-	(_Generic((_fdf), struct fd_prepare: (_fdf).__file))
-
 /* Do not use directly. */
-static inline void class_fd_prepare_destructor(const struct fd_prepare *fdf)
+static __always_inline void __fd_prepare_cleanup(const struct fd_prepare *fdf)
 {
-	if (unlikely(fdf->__fd >= 0))
-		put_unused_fd(fdf->__fd);
-	if (unlikely(!IS_ERR_OR_NULL(fdf->__file)))
-		fput(fdf->__file);
+	if (unlikely(fdf->fd >= 0)) {
+		put_unused_fd(fdf->fd);
+		fput(fdf->file);
+	}
 }
 
 /* Do not use directly. */
-static inline int class_fd_prepare_lock_err(const struct fd_prepare *fdf)
+static __always_inline struct fd_prepare __fd_prepare(int fd, struct file *file)
 {
-	if (unlikely(fdf->err))
-		return fdf->err;
-	if (unlikely(fdf->__fd < 0))
-		return fdf->__fd;
-	if (unlikely(IS_ERR(fdf->__file)))
-		return PTR_ERR(fdf->__file);
-	if (unlikely(!fdf->__file))
-		return -ENOMEM;
-	return 0;
+	if (fd >= 0 && IS_ERR_OR_NULL(file)) {
+		int err = file ? PTR_ERR(file) : -ENOMEM;
+
+		put_unused_fd(fd);
+		fd = err;
+		file = NULL;
+	}
+	return (struct fd_prepare){ .fd = fd, .file = file };
 }
 
 /*
- * __FD_PREPARE_INIT - Helper to initialize fd_prepare class.
- * @_fd_flags: flags for get_unused_fd_flags()
- * @_file_owned: expression that returns struct file *
- *
- * Returns a struct fd_prepare with fd, file, and err set.
- * If fd allocation fails, fd will be negative and err will be set. If
- * fd succeeds but file_init_expr fails, file will be ERR_PTR and err
- * will be set. The err field is the single source of truth for error
- * checking.
- */
-#define __FD_PREPARE_INIT(_fd_flags, _file_owned)                 \
-	({                                                        \
-		struct fd_prepare fdf = {                         \
-			.__fd = get_unused_fd_flags((_fd_flags)), \
-		};                                                \
-		if (likely(fdf.__fd >= 0))                        \
-			fdf.__file = (_file_owned);               \
-		fdf.err = ACQUIRE_ERR(fd_prepare, &fdf);          \
-		fdf;                                              \
-	})
-
-/*
- * FD_PREPARE - Macro to declare and initialize an fd_prepare variable.
+ * FD_PREPARE - Declare and initialize an fd_prepare instance.
  *
- * Declares and initializes an fd_prepare variable with automatic
- * cleanup. No separate scope required - cleanup happens when variable
- * goes out of scope.
+ * This allocates a new fd and only evaluates @_file_owned if the
+ * allocation succeeded. Cleanup happens when the variable goes out of
+ * scope and the guard releases whichever of the descriptor and the file
+ * was allocated. If fd_publish() was called the fd and file are
+ * published and cleanup becomes a nop.
  *
- * @_fdf: name of struct fd_prepare variable to define
+ * @_fdf: name of the const struct fd_prepare pointer to define
  * @_fd_flags: flags for get_unused_fd_flags()
  * @_file_owned: struct file to take ownership of (can be expression)
  */
+#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)		\
+	struct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({	\
+		int __fd = get_unused_fd_flags(_fd_flags);		\
+		__fd_prepare(__fd, __fd < 0 ? NULL : (_file_owned));	\
+	});								\
+	const struct fd_prepare *const _fdf = &_guard
+
 #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \
-	CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))
+	__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)
 
 /*
  * fd_publish - Publish prepared fd and file to the fd table.
- * @_fdf: struct fd_prepare variable
+ * @fdf: struct fd_prepare pointer defined by FD_PREPARE()
  */
-#define fd_publish(_fdf)                                       \
-	({                                                     \
-		struct fd_prepare *fdp = &(_fdf);              \
-		VFS_WARN_ON_ONCE(fdp->err);                    \
-		VFS_WARN_ON_ONCE(fdp->__fd < 0);               \
-		VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \
-		fd_install(fdp->__fd, fdp->__file);            \
-		retain_and_null_ptr(fdp->__file);              \
-		take_fd(fdp->__fd);                            \
-	})
+static __always_inline int fd_publish(const struct fd_prepare *fdf)
+{
+	/* Callers only get a const view, the guard itself is writable. */
+	struct fd_prepare *guard = (struct fd_prepare *)fdf;
+
+	VFS_WARN_ON_ONCE(guard->fd < 0);
+	fd_install(guard->fd, guard->file);
+	return take_fd(guard->fd);
+}
 
 /* Do not use directly. */
-#define __FD_ADD(_fdf, _fd_flags, _file_owned)            \
-	({                                                \
-		FD_PREPARE(_fdf, _fd_flags, _file_owned); \
-		s32 ret = _fdf.err;                       \
-		if (likely(!ret))                         \
-			ret = fd_publish(_fdf);           \
-		ret;                                      \
+#define __FD_ADD(_fdf, _fd_flags, _file_owned)			\
+	({							\
+		FD_PREPARE(_fdf, _fd_flags, _file_owned);	\
+		_fdf->fd < 0 ? _fdf->fd : fd_publish(_fdf);	\
 	})
 
 /*
diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c
index b318ed697998e..9f0b4d850c12f 100644
--- a/io_uring/mock_file.c
+++ b/io_uring/mock_file.c
@@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
 	FD_PREPARE(fdf, O_RDWR | O_CLOEXEC,
 		   anon_inode_create_getfile("[io_uring_mock]", fops, mf,
 					     O_RDWR | O_CLOEXEC, NULL));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	retain_and_null_ptr(mf);
-	file = fd_prepare_file(fdf);
+	file = fdf->file;
 	file->f_mode |= FMODE_READ | FMODE_CAN_READ | FMODE_WRITE |
 			FMODE_CAN_WRITE | FMODE_LSEEK;
 	if (mc.flags & IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)
 		file->f_mode |= FMODE_NOWAIT;
 
-	mc.out_fd = fd_prepare_fd(fdf);
+	mc.out_fd = fdf->fd;
 	if (copy_to_user(uarg, &mc, uarg_size))
 		return -EFAULT;
 
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 14a5fdfa04214..5f790d12f72e1 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link *link)
 	flags = O_RDONLY | O_CLOEXEC;
 
 	FD_PREPARE(fdf, flags, anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	iter_link = container_of(link, struct bpf_iter_link, link);
-	err = prepare_seq_file(fd_prepare_file(fdf), iter_link);
+	err = prepare_seq_file(fdf->file, iter_link);
 	if (err)
 		return err; /* Automatic cleanup handles fput */
 
diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c
index e85a179523f02..da915a4f972b1 100644
--- a/kernel/bpf/token.c
+++ b/kernel/bpf/token.c
@@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr *attr)
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME,
 				     O_RDWR, &bpf_token_fops));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	token = kzalloc_obj(*token, GFP_USER);
 	if (!token)
@@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr *attr)
 		return err;
 
 	get_user_ns(token->userns);
-	fd_prepare_file(fdf)->private_data = no_free_ptr(token);
+	fdf->file->private_data = no_free_ptr(token);
 	return fd_publish(fdf);
 }
 
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 23fb68fce000e..ea382aedfc90d 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags)
 		   anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
 					     O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS),
 					     NULL));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	/* prevent the mm struct to be freed */
 	mmgrab(ctx->mm);
-	fd_prepare_file(fdf)->f_mode |= FMODE_NOWAIT;
+	fdf->file->f_mode |= FMODE_NOWAIT;
 	retain_and_null_ptr(ctx);
 	return fd_publish(fdf);
 }
diff --git a/net/core/scm.c b/net/core/scm.c
index f0d44ecdb11fc..15c330784a699 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file *f, int __user *ufd, unsigned int flags,
 		return notrunc ? put_user(error, ufd) : error;
 
 	FD_PREPARE(fdf, flags, get_file(f));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
-	error = put_user(fd_prepare_fd(fdf), ufd);
+	error = put_user(fdf->fd, ufd);
 	if (error)
 		return error;
 
-	__receive_sock(fd_prepare_file(fdf));
+	__receive_sock(fdf->file);
 	return fd_publish(fdf);
 }
 
diff --git a/net/handshake/netlink.c b/net/handshake/netlink.c
index 3fd4fef9bab1a..73b8314d9010c 100644
--- a/net/handshake/netlink.c
+++ b/net/handshake/netlink.c
@@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 	req = handshake_req_next(hn, class);
 	if (req) {
 		FD_PREPARE(fdf, O_CLOEXEC, req->hr_file);
-		if (fdf.err) {
+		if (fdf->fd < 0) {
 			fput(req->hr_file); /* drop ref from handshake_req_next() */
-			err = fdf.err;
+			err = fdf->fd;
 			goto out_complete;
 		}
 
-		err = req->hr_proto->hp_accept(req, info, fd_prepare_fd(fdf));
+		err = req->hr_proto->hp_accept(req, info, fdf->fd);
 		if (err)
 			goto out_complete; /* Automatic cleanup handles fput */
 
-		trace_handshake_cmd_accept(net, req, req->hr_sk, fd_prepare_fd(fdf));
+		trace_handshake_cmd_accept(net, req, req->hr_sk, fdf->fd);
 		fd_publish(fdf);
 		return 0;
 	}
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 71af69d442f21..962ee2c4acd2f 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct kcm_clone info;
 
 		FD_PREPARE(fdf, 0, kcm_clone(sock));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 
-		info.fd = fd_prepare_fd(fdf);
+		info.fd = fdf->fd;
 		if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 			return -EFAULT;

3/2

2026/09/19 01:36

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 11715
							output: 30
							thoughts: 1279

Thoughts:

**Analyzing the `fd_prepare` Abstraction Refactor**

Okay, let's dive into this patch. The target architecture is amd64, so we need to keep that in mind. The commit touches quite a few subsystems, which suggests this is a relatively widespread, core change. We have `arch/powerpc/platforms/cell/spufs/inode.c`, `drivers/gpio/gpiolib-cdev.c`, `drivers/gpu/drm/msm/msm_perfcntr.c`, and so on. That means this has the potential to impact a good chunk of the kernel.

The key seems to be the refactoring of the `fd_prepare` abstraction in `include/linux/file.h`. Let's compare the before and after versions.  It appears they've streamlined the struct itself. Previously, there were these internal members `__fd` and `__file`, which were hidden. Now, we have direct members: `int fd` and `struct file *file`. This looks cleaner and more direct.

The original had a `class_fd_prepare_t` alias and a destructor `class_fd_prepare_destructor`. The destructor handled releasing the file descriptor and the file itself. Now, this seems to have been broken into two functions, an inline `__fd_prepare_cleanup` and `__fd_prepare` to deal with the `fd` and the `file`.

Now, the macro `FD_PREPARE` is the point of interest. What does `__FD_PREPARE` do? It creates a temporary variable, uses a `__cleanup` attribute to call `__fd_prepare_cleanup`, and then assigns a struct to `_fdf`. Seems safe.

And what's this? They've also refactored the `fd_publish` macro. This is where things get interesting.  Previously, `fd_publish` used `retain_and_null_ptr(fdp->__file)`. Where the previous implementation relied on a set of `VFS_WARN_ON_ONCE` and `retain_and_null_ptr`, the current version, the caller gets a `const` view of the `_fdf`, and that `fd_publish` function uses `fd_install` and `take_fd`. I need to understand what `take_fd` *actually* does. Let's dig into that `take_fd` function in `include/linux/file.h`. That's where the real magic happens, so let's see exactly what's changed there.

4/2

2026/09/19 01:36

tool

grepper

Args:

{
  "Expression": "take_fd",
  "PathPrefix": "include/linux/file.h"
}

Results:

{
  "Output": "include/linux/file.h=98=DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))\n--\ninclude/linux/file.h-100-/*\ninclude/linux/file.h:101: * take_fd() will take care to set @fd to -EBADF ensuring that\ninclude/linux/file.h-102- * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it\n--\ninclude/linux/file.h-115- * fd_install(fd, f);\ninclude/linux/file.h:116: * return take_fd(fd);\ninclude/linux/file.h-117- */\ninclude/linux/file.h:118:#define take_fd(fd) __get_and_null(fd, -EBADF)\ninclude/linux/file.h-119-\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare *fdf)\n--\ninclude/linux/file.h-202-\tfd_install(guard-\u003efd, guard-\u003efile);\ninclude/linux/file.h:203:\treturn take_fd(guard-\u003efd);\ninclude/linux/file.h-204-}\n"
}

5/2

2026/09/19 01:36

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 13916
							output: 34
							thoughts: 1546

Thoughts:

**Analyzing Potential Kernel File Descriptor Vulnerabilities**

Okay, let's break this down. My initial thought process revolves around a specific pattern in the Linux kernel: the use of `FD_PREPARE` and `fd_publish` for file descriptor management, along with the associated cleanup functions, namely `__fd_prepare_cleanup`. I immediately recognize the importance of meticulously tracing the execution paths and potential error conditions within this specific design.

My first observation is the `take_fd(guard->fd)` macro, which sets the file descriptor `guard->fd` to -EBADF if the FD is not valid. That's my starting point. The crucial question is: under what circumstances does the kernel *not* publish an FD, and what happens during the subsequent cleanup? I'm looking for race conditions and vulnerabilities, where the intended FD management might be bypassed.

The code for `__fd_prepare_cleanup` is clear: it will check if `fdf->fd` is greater than or equal to zero and if so call `put_unused_fd` and `fput`. But, what if an error occurs *before* `fd_publish` is called? The initial FD might be valid, but then get set to a negative error code. If so, and the error happens before publish, `put_unused_fd` and `fput` will be called, as the check `fdf->fd >= 0` is still true at this stage. I immediately realize that this might lead to a double-free or use-after-free, if that FD has been released by the error handling.

The interesting thing is if `_file_owned` fails. This is handled by `__fd_prepare`, but the key here is what happens if `file` is NULL or an error pointer. If it is, then `put_unused_fd(fd)` is called *immediately*, `fd` is set to negative, and `file` is set to NULL. My thought is, on cleanup, the cleanup function will see a negative FD, and do nothing, but the FD *could* have already been put back into the unused FD table. That means that the FD could potentially have been cleaned up twice.

I'm thinking about whether this could be reached in amd64. I recognize that there are several core system calls that use `FD_PREPARE`. Specifically, eventfd, epoll_create, fsmount, open_tree, receive_fd, userfaultfd, and bpf_iter_new_fd are among the many syscalls and subsystems in Linux that use this. It is quite clear that any logic modifications in memory management, synchronization/locking, BPF, scheduler, core networking, VFS, or syscall handling should be carefully examined. Refactorings and code cleanups also need to be very carefully reviewed because they are frequently the sources of subtle bugs.

The cleanup function `__fd_prepare_cleanup` is worth examining. The interesting part here is that `fdf->file` could be NULL or an ERR_PTR if it was prepared that way. It is important to know that if `fdf->fd >= 0`, `fdf->file` must be a valid file pointer, which I am comfortable with because of the logic.

I immediately start to look for vulnerable code paths that might result in `fd_publish` not being called, especially situations after a valid FD preparation. `drivers/gpio/gpiolib-cdev.c` immediately catches my eye. If `copy_to_user` fails in the code there, the scope ends, `__fd_prepare_cleanup` is called. That means that `put_unused_fd(fdf->fd)` and `fput(fdf->file)` are called!

I shift my attention to `drivers/media/mc/mc-request.c`. It's another potential location, but I notice that the code sets `fdf->file->private_data = req`. I start to wonder if there could be a case where the file is cleaned up, but the data is not.

Now I'm looking at `fs/eventfd.c` and specifically `do_eventfd`. What happens if the `ida_alloc` call fails? Is there a path to a double free, or a missed cleanup? I need to dig into the eventfd code to see what that branch does, and what state it leaves the file descriptor and associated data in. I'm focusing on the exact sequence of events, and where errors can interrupt the normal `fd_publish` flow.

6/2

2026/09/19 01:37

tool

read-file

Args:

{
  "File": "fs/eventfd.c",
  "FirstLine": 390,
  "LineCount": 40
}

Results:

{
  "Contents": " 390:\t\n 391:\t\tctx = kmalloc_obj(*ctx);\n 392:\t\tif (!ctx)\n 393:\t\t\treturn -ENOMEM;\n 394:\t\n 395:\t\tkref_init(\u0026ctx-\u003ekref);\n 396:\t\tinit_waitqueue_head(\u0026ctx-\u003ewqh);\n 397:\t\tctx-\u003ecount = count;\n 398:\t\tctx-\u003eflags = flags;\n 399:\t\n 400:\t\tflags \u0026= EFD_SHARED_FCNTL_FLAGS;\n 401:\t\tflags |= O_RDWR;\n 402:\t\n 403:\t\tFD_PREPARE(fdf, flags,\n 404:\t\t\t   anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n 405:\t\t\t\t\t\t    flags, FMODE_NOWAIT));\n 406:\t\tif (fdf-\u003efd \u003c 0)\n 407:\t\t\treturn fdf-\u003efd;\n 408:\t\n 409:\t\tctx-\u003eid = ida_alloc(\u0026eventfd_ida, GFP_KERNEL);\n 410:\t\tretain_and_null_ptr(ctx);\n 411:\t\treturn fd_publish(fdf);\n 412:\t}\n 413:\t\n 414:\tSYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)\n 415:\t{\n 416:\t\treturn do_eventfd(count, flags);\n 417:\t}\n 418:\t\n 419:\tSYSCALL_DEFINE1(eventfd, unsigned int, count)\n 420:\t{\n 421:\t\treturn do_eventfd(count, 0);\n 422:\t}\n 423:\t\n"
}

7/2

2026/09/19 01:37

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 16947
							output: 34
							thoughts: 39

Thoughts:

Okay, here's my interpretation of that thought process, assuming I'm deep in the code:

**Diving into `retain_and_null_ptr(ctx)`**

Alright, let's dissect this `retain_and_null_ptr(ctx)` call. Hold on a sec... *ctx*. Hmm, I need to immediately understand the context of `ctx`. Let's skip to the declaration real quick. Line numbers 380 to 395 should hold the key, I'll go check those lines. That's where I need to start to understand what's actually going on here with this call.

8/2

2026/09/19 01:37

tool

read-file

Args:

{
  "File": "fs/eventfd.c",
  "FirstLine": 380,
  "LineCount": 15
}

Results:

{
  "Contents": " 380:\t{\n 381:\t\tstruct eventfd_ctx *ctx __free(kfree) = NULL;\n 382:\t\n 383:\t\t/* Check the EFD_* constants for consistency.  */\n 384:\t\tBUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);\n 385:\t\tBUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);\n 386:\t\tBUILD_BUG_ON(EFD_SEMAPHORE != (1 \u003c\u003c 0));\n 387:\t\n 388:\t\tif (flags \u0026 ~EFD_FLAGS_SET)\n 389:\t\t\treturn -EINVAL;\n 390:\t\n 391:\t\tctx = kmalloc_obj(*ctx);\n 392:\t\tif (!ctx)\n 393:\t\t\treturn -ENOMEM;\n 394:\t\n"
}

9/2

2026/09/19 01:37

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 17395
							output: 35
							thoughts: 38

Thoughts:

Okay, let's dive into this.

**Examining `do_epoll_create`**

Right, so I need to understand the initial setup for epoll. Let's head over to `fs/eventpoll.c` and specifically focus on the `do_epoll_create` function. I want to zero in on lines 2500 through 2530. Those lines should cover the core initialization. I'll be looking for how the data structures are allocated and initialized, any security checks, and how the file descriptor is assigned. My experience tells me this is where the groundwork is laid, so this is the best place to find the kernel's first steps in setting up an epoll instance. Let's see what we're working with here!

10/2

2026/09/19 01:37

tool

read-file

Args:

{
  "File": "fs/eventpoll.c",
  "FirstLine": 2500,
  "LineCount": 30
}

Results:

{
  "Contents": "2500:\t\tBUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);\n2501:\t\n2502:\t\tif (flags \u0026 ~EPOLL_CLOEXEC)\n2503:\t\t\treturn -EINVAL;\n2504:\t\t/*\n2505:\t\t * Create the internal data structure (\"struct eventpoll\").\n2506:\t\t */\n2507:\t\terror = ep_alloc(\u0026ep);\n2508:\t\tif (error \u003c 0)\n2509:\t\t\treturn error;\n2510:\t\t/*\n2511:\t\t * Creates all the items needed to setup an eventpoll file. That is,\n2512:\t\t * a file structure and a free file descriptor.\n2513:\t\t */\n2514:\t\tFD_PREPARE(fdf, O_RDWR | (flags \u0026 O_CLOEXEC),\n2515:\t\t\t   anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n2516:\t\t\t\t\t      O_RDWR | (flags \u0026 O_CLOEXEC)));\n2517:\t\tif (fdf-\u003efd \u003c 0) {\n2518:\t\t\tep_clear_and_put(ep);\n2519:\t\t\treturn fdf-\u003efd;\n2520:\t\t}\n2521:\t\tep-\u003efile = fdf-\u003efile;\n2522:\t\treturn fd_publish(fdf);\n2523:\t}\n2524:\t\n2525:\tSYSCALL_DEFINE1(epoll_create1, int, flags)\n2526:\t{\n2527:\t\treturn do_epoll_create(flags);\n2528:\t}\n2529:\t\n"
}

11/2

2026/09/19 01:37

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 18086
							output: 34
							thoughts: 33

Thoughts:

Okay, let's dive into this. I need to understand how file descriptors are received in the kernel, so I'll zero in on `receive_fd` within `fs/file.c`. Specifically, I'm going to focus on lines 1380 through 1415. I'm expecting this section to illuminate the mechanism by which file descriptors are transferred, potentially across processes or through a socket, and how the kernel handles the reception and validation of these descriptors. I'll be looking for the crucial data structures involved – the relevant `struct file`, `struct fdtable`, perhaps some socket-related structures if inter-process communication is involved – and how the kernel ensures the integrity and security of the transferred file descriptors. I'm anticipating some intricate pointer management and reference counting to be in play here, as well as some careful checks to prevent resource leaks and potential security vulnerabilities. Time to dig in and see how the kernel engineers solved this.

12/2

2026/09/19 01:37

tool

read-file

Args:

{
  "File": "fs/file.c",
  "FirstLine": 1380,
  "LineCount": 35
}

Results:

{
  "Contents": "1380:\t * This helper handles its own reference counting of the incoming\n1381:\t * struct file.\n1382:\t *\n1383:\t * Returns newly install fd or -ve on error.\n1384:\t */\n1385:\tint receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)\n1386:\t{\n1387:\t\tint error;\n1388:\t\n1389:\t\terror = security_file_receive(file);\n1390:\t\tif (error)\n1391:\t\t\treturn error;\n1392:\t\n1393:\t\tFD_PREPARE(fdf, o_flags, file);\n1394:\t\tif (fdf-\u003efd \u003c 0)\n1395:\t\t\treturn fdf-\u003efd;\n1396:\t\tget_file(file);\n1397:\t\n1398:\t\tif (ufd) {\n1399:\t\t\terror = put_user(fdf-\u003efd, ufd);\n1400:\t\t\tif (error)\n1401:\t\t\t\treturn error;\n1402:\t\t}\n1403:\t\n1404:\t\t__receive_sock(fdf-\u003efile);\n1405:\t\treturn fd_publish(fdf);\n1406:\t}\n1407:\tEXPORT_SYMBOL_GPL(receive_fd);\n1408:\t\n1409:\tint receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)\n1410:\t{\n1411:\t\tint error;\n1412:\t\n1413:\t\terror = security_file_receive(file);\n1414:\t\tif (error)\n"
}

13/2

2026/09/19 01:37

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 18819
							output: 22
							thoughts: 3384

Thoughts:

**Analyzing File Descriptor Management in Kernel Code**

Okay, let's break this down. My initial focus is on the `receive_fd` function in `fs/file.c` and how it handles file descriptors (FDs). It looks like this code is going through a refactor, and I need to understand the implications of the changes.

Initially, I'm concerned about the behavior when `put_user` fails in `receive_fd`. The core of the problem seems to be the lifetime management of the `struct file` pointer associated with the FD.

First, I see the old `FD_PREPARE` macro used a struct member `fdf.err`. Now it appears that we have `fdf->fd < 0`, so I need to figure out how this is different now. I recall how it was initialized: `FD_PREPARE(fdf, o_flags, file);`. This macro sets up an unused FD and associates it with a `file` pointer, acquiring a reference count. The critical change is in how the cleanup is handled.

The old code had `class_fd_prepare_destructor`, which would call `fput(file)` to release the reference if `put_user` failed. This makes sense: the FD gets cleaned up, and the file reference is dropped. The current approach uses `__fd_prepare_cleanup`.

Now, the `fd_publish` function used to set the `__file` pointer to NULL and set `__fd` to -EBADF! This suggests that, in the event of success, the `file` pointer should be released. However, in the *new* `fd_publish`, there is no modification to the `guard->file`. This seems like a potential leak, but the guard now makes sure `__fd_prepare_cleanup` is run at the end of the `guard` lifetime, regardless.

I notice that the new `fd_publish` no longer handles the `file` pointer. This is where I start to see a difference with the old code. Looking at the cleanup function `__fd_prepare_cleanup`, the check `fdf->fd >= 0` is now crucial. If it's *false* (because of `take_fd`), neither `put_unused_fd` nor `fput` is called *after* a successful `fd_publish`, and therefore no leak!

Now I'm turning my attention to the `scm_recv_one_fd` function. The process flow is similar to `receive_fd`. I see that the order of `FD_PREPARE` and `get_file` calls is crucial because the old code ensures that `fput` drops the reference that `get_file` provides.

So, in the original `receive_fd` code with the `ACQUIRE_ERR` macro, `get_file` was called and later, the refcount was properly dropped by `fput(file)` when an error occurs, or at the end of `fd_publish`. This avoids refcount leaks or underflows.

I see that the new `__fd_prepare` function handles the initial error cases by either releasing the FD or setting `file` to `NULL`. The cleanup of the file pointer is now done only in the destructor when things go wrong.

Then, I'm checking what happens in `net/handshake/netlink.c`, in the context of `netlink` connections. In this specific scenario, a `file` reference is acquired using `handshake_req_next`. I note the `fput` call if `fdf->fd < 0` to release the refcount acquired. Otherwise if `hp_accept` fails, the destructor does a clean-up.

I need to emphasize that the most impactful change here involves how `fdf` is now a *pointer* (`const struct fd_prepare *const _fdf`) instead of a `struct fd_prepare` by value. Previously, `fdf.err` was used, but now `fdf->fd < 0` is the check. The key difference is how the FD is managed throughout the process.  The original use of the struct member, `fdf.err`, is now replaced with pointer dereference, `fdf->fd < 0`. This subtle pointer use is critical for understanding the refcount changes.

The focus is now ensuring that the file object is correctly released when the FD goes out of scope and, in particular, when an error occurs.

14/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "__FD_ADD|FD_ADD"
}

Results:

{
  "Output": "arch/powerpc/platforms/pseries/papr-hvpipe.c=485=static int papr_hvpipe_dev_create_handle(u32 srcID)\n--\narch/powerpc/platforms/pseries/papr-hvpipe.c-512-\narch/powerpc/platforms/pseries/papr-hvpipe.c:513:\tfd = FD_ADD(O_RDONLY | O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-hvpipe.c-514-\t\t   anon_inode_getfile(\"[papr-hvpipe]\", \u0026papr_hvpipe_handle_ops,\n--\narch/powerpc/platforms/pseries/papr-platform-dump.c=302=static long papr_platform_dump_create_handle(u64 dump_tag)\n--\narch/powerpc/platforms/pseries/papr-platform-dump.c-334-\narch/powerpc/platforms/pseries/papr-platform-dump.c:335:\tfd = FD_ADD(O_RDONLY | O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-platform-dump.c-336-\t\t    anon_inode_getfile_fmode(\"[papr-platform-dump]\",\n--\narch/powerpc/platforms/pseries/papr-rtas-common.c=203=long papr_rtas_setup_file_interface(struct papr_rtas_sequence *seq,\n--\narch/powerpc/platforms/pseries/papr-rtas-common.c-213-\narch/powerpc/platforms/pseries/papr-rtas-common.c:214:\tfd = FD_ADD(O_RDONLY | O_CLOEXEC,\narch/powerpc/platforms/pseries/papr-rtas-common.c-215-\t\t   anon_inode_getfile_fmode(name, fops, (void *)blob, O_RDONLY,\n--\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c=695=static int a5xx_hw_init(struct msm_gpu *gpu)\n--\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c-901-\tgpu_write(gpu, REG_A5XX_HLSQ_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c:902:\tgpu_write(gpu, REG_A5XX_VFD_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a5xx_gpu.c-903-\tgpu_write(gpu, REG_A5XX_VPC_ADDR_MODE_CNTL, 0x1);\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c=1173=static int hw_init(struct msm_gpu *gpu)\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c-1224-\t\tgpu_write(gpu, REG_A6XX_HLSQ_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c:1225:\t\tgpu_write(gpu, REG_A6XX_VFD_ADDR_MODE_CNTL, 0x1);\ndrivers/gpu/drm/msm/adreno/a6xx_gpu.c-1226-\t\tgpu_write(gpu, REG_A6XX_VPC_ADDR_MODE_CNTL, 0x1);\n--\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml=4=xsi:schemaLocation=\"https://gitlab.freedesktop.org/freedreno/ rules-fd.xsd\"\u003e\n--\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml-1529-\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml:1530:\t\u003creg32 offset=\"0x0e41\" name=\"VFD_ADDR_MODE_CNTL\" type=\"a5xx_address_mode\"/\u003e\ndrivers/gpu/drm/msm/registers/adreno/a5xx.xml-1531-\t\u003creg32 offset=\"0x0e42\" name=\"VFD_MODE_CNTL\"/\u003e \u003c!-- always 00000000? --\u003e\n--\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml=32=by a particular renderpass/blit.\n--\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml-3578-\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml:3579:\t\u003creg32 offset=\"0xa601\" name=\"VFD_ADDR_MODE_CNTL\" type=\"a5xx_address_mode\" variants=\"A6XX\"/\u003e\ndrivers/gpu/drm/msm/registers/adreno/a6xx.xml-3580-\t\u003carray offset=\"0xa610\" name=\"VFD_PERFCTR_VFD_SEL\" stride=\"1\" length=\"8\" variants=\"A6XX\"/\u003e\n--\ndrivers/hv/mshv_root_main.c=2048=mshv_ioctl_create_partition(void __user *user_arg, struct device *module_dev)\n--\ndrivers/hv/mshv_root_main.c-2107-\ndrivers/hv/mshv_root_main.c:2108:\tret = FD_ADD(O_CLOEXEC, anon_inode_getfile(\"mshv_partition\",\ndrivers/hv/mshv_root_main.c-2109-\t\t\t\t\t\t   \u0026mshv_partition_fops,\n--\ndrivers/net/ethernet/atheros/alx/main.c=450=static void alx_init_ring_ptrs(struct alx_priv *alx)\n--\ndrivers/net/ethernet/atheros/alx/main.c-471-\t\t\talx_write_mem32(hw, ALX_RRD_ADDR_LO, np-\u003erxq-\u003errd_dma);\ndrivers/net/ethernet/atheros/alx/main.c:472:\t\t\talx_write_mem32(hw, ALX_RFD_ADDR_LO, np-\u003erxq-\u003erfd_dma);\ndrivers/net/ethernet/atheros/alx/main.c-473-\t\t}\n--\ndrivers/net/ethernet/atheros/alx/reg.h-295-\ndrivers/net/ethernet/atheros/alx/reg.h:296:#define ALX_RFD_ADDR_LO\t\t\t\t\t0x1550\ndrivers/net/ethernet/atheros/alx/reg.h-297-#define ALX_RFD_RING_SZ\t\t\t\t\t0x1560\n--\ndrivers/net/ethernet/atheros/atlx/atl1.c=1451=static u32 atl1_configure(struct atl1_adapter *adapter)\n--\ndrivers/net/ethernet/atheros/atlx/atl1.c-1474-\tiowrite32((u32) (adapter-\u003erfd_ring.dma \u0026 0x00000000ffffffffULL),\ndrivers/net/ethernet/atheros/atlx/atl1.c:1475:\t\thw-\u003ehw_addr + REG_DESC_RFD_ADDR_LO);\ndrivers/net/ethernet/atheros/atlx/atl1.c-1476-\tiowrite32((u32) (adapter-\u003errd_ring.dma \u0026 0x00000000ffffffffULL),\n--\ndrivers/net/ethernet/atheros/atlx/atl1.h=51=static u32 atl1_check_link(struct atl1_adapter *adapter);\n--\ndrivers/net/ethernet/atheros/atlx/atl1.h-121-/* Descriptor Control registers, low 32 bits */\ndrivers/net/ethernet/atheros/atlx/atl1.h:122:#define REG_DESC_RFD_ADDR_LO\t\t\t0x1544\ndrivers/net/ethernet/atheros/atlx/atl1.h-123-#define REG_DESC_RRD_ADDR_LO\t\t\t0x1548\n--\ndrivers/net/ethernet/atheros/atlx/atlx.h-268-/* Internal SRAM Partition Register, high 32 bits */\ndrivers/net/ethernet/atheros/atlx/atlx.h:269:#define REG_SRAM_RFD_ADDR\t\t0x1500\ndrivers/net/ethernet/atheros/atlx/atlx.h-270-\n--\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h=22=enum {\n--\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h-578-#define CR_READ_TCB_ADDR\t\tCTL_REG(0x06E8)\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h:579:#define CR_READ_RFD_ADDR\t\tCTL_REG(0x06EC)\ndrivers/net/wireless/zydas/zd1211rw/zd_chip.h-580-#define CR_CWMIN_CWMAX\t\t\tCTL_REG(0x06F0)\n--\ndrivers/tty/pty.c=617=int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)\n--\ndrivers/tty/pty.c-621-\ndrivers/tty/pty.c:622:\treturn FD_ADD(flags, ptm_open_peer_file(master, tty, flags));\ndrivers/tty/pty.c-623-}\n--\ndrivers/vfio/group.c=303=static int vfio_group_ioctl_get_device_fd(struct vfio_group *group,\n--\ndrivers/vfio/group.c-318-\ndrivers/vfio/group.c:319:\tfd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));\ndrivers/vfio/group.c-320-\tif (fd \u003c 0)\n--\nfs/anon_inodes.c=275=static int __anon_inode_getfd(const char *name,\n--\nfs/anon_inodes.c-280-{\nfs/anon_inodes.c:281:\treturn FD_ADD(flags, __anon_inode_getfile(name, fops, priv, flags,\nfs/anon_inodes.c-282-\t\t\t\t\t\t  context_inode, make_inode));\n--\nfs/autofs/dev-ioctl.c=232=static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)\n--\nfs/autofs/dev-ioctl.c-240-\nfs/autofs/dev-ioctl.c:241:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/autofs/dev-ioctl.c-242-}\n--\nfs/exec.c=1124=int begin_new_exec(struct linux_binprm * bprm)\n--\nfs/exec.c-1318-\t\tbprm-\u003eexecutable = NULL;\nfs/exec.c:1319:\t\tretval = FD_ADD(0, executable);\nfs/exec.c-1320-\t\tif (retval \u003c 0) {\n--\nfs/fhandle.c=427=static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,\n--\nfs/fhandle.c-436-\nfs/fhandle.c:437:\treturn FD_ADD(open_flag, file_open_handle(\u0026path, open_flag));\nfs/fhandle.c-438-}\n--\nfs/namespace.c=3248=SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags)\nfs/namespace.c-3249-{\nfs/namespace.c:3250:\treturn FD_ADD(flags, vfs_open_tree(dfd, filename, flags));\nfs/namespace.c-3251-}\n--\nfs/namespace.c=4442=SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n--\nfs/namespace.c-4532-\tif (flags \u0026 FSMOUNT_NAMESPACE)\nfs/namespace.c:4533:\t\treturn FD_ADD((flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\nfs/namespace.c-4534-\t\t\t      open_new_namespace(\u0026new_path, MOUNT_COPY_NEW));\n--\nfs/notify/fanotify/fanotify_user.c=1589=SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)\n--\nfs/notify/fanotify/fanotify_user.c-1727-\nfs/notify/fanotify/fanotify_user.c:1728:\tfd = FD_ADD(f_flags,\nfs/notify/fanotify/fanotify_user.c-1729-\t\t    anon_inode_getfile_fmode(\"[fanotify]\", \u0026fanotify_fops,\n--\nfs/nsfs.c=123=int open_namespace(struct ns_common *ns)\n--\nfs/nsfs.c-132-\nfs/nsfs.c:133:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/nsfs.c-134-}\n--\nfs/open.c=1408=static int do_sys_openat2(int dfd, const char __user *filename,\n--\nfs/open.c-1416-\tCLASS(filename_flags, name)(filename, op.lookup_flags);\nfs/open.c:1417:\treturn FD_ADD(how-\u003eflags, do_file_open(dfd, name, \u0026op));\nfs/open.c-1418-}\n--\nfs/signalfd.c=251=static int do_signalfd4(int ufd, sigset_t *mask, int flags)\n--\nfs/signalfd.c-272-\nfs/signalfd.c:273:\t\tfd = FD_ADD(flags \u0026 O_CLOEXEC,\nfs/signalfd.c-274-\t\t\t    anon_inode_getfile_fmode(\n--\nfs/timerfd.c=424=SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)\n--\nfs/timerfd.c-463-\nfs/timerfd.c:464:\tret = FD_ADD(flags \u0026 TFD_SHARED_FCNTL_FLAGS,\nfs/timerfd.c-465-\t\t     anon_inode_getfile_fmode(\"[timerfd]\", \u0026timerfd_fops, ctx,\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare *fdf)\n--\ninclude/linux/file.h-206-/* Do not use directly. */\ninclude/linux/file.h:207:#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\ninclude/linux/file.h-208-\t({\t\t\t\t\t\t\t\\\n--\ninclude/linux/file.h-213-/*\ninclude/linux/file.h:214: * FD_ADD - Allocate and install an fd and file in one step.\ninclude/linux/file.h-215- * @_fd_flags: flags for get_unused_fd_flags()\n--\ninclude/linux/file.h-219- */\ninclude/linux/file.h:220:#define FD_ADD(_fd_flags, _file_owned) \\\ninclude/linux/file.h:221:\t__FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)\ninclude/linux/file.h-222-\n--\nipc/mqueue.c=910=static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,\n--\nipc/mqueue.c-922-\tro = mnt_want_write(mnt);\t/* we'll drop it in any case */\nipc/mqueue.c:923:\tfd = FD_ADD(O_CLOEXEC, mqueue_file_open(name, mnt, oflag, ro, mode, attr));\nipc/mqueue.c-924-\tif (!ro)\n--\nmm/memfd.c=503=SYSCALL_DEFINE2(memfd_create,\n--\nmm/memfd.c-519-\tfd_flags = (flags \u0026 MFD_CLOEXEC) ? O_CLOEXEC : 0;\nmm/memfd.c:520:\treturn FD_ADD(fd_flags, memfd_alloc_file(name, flags));\nmm/memfd.c-521-}\n--\nmm/secretmem.c=224=SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)\n--\nmm/secretmem.c-236-\nmm/secretmem.c:237:\treturn FD_ADD(flags \u0026 O_CLOEXEC, secretmem_file_create(flags));\nmm/secretmem.c-238-}\n--\nnet/socket.c=2082=static int __sys_accept4_file(struct file *file, struct sockaddr __user *upeer_sockaddr,\n--\nnet/socket.c-2092-\nnet/socket.c:2093:\treturn FD_ADD(flags, do_accept(file, \u0026arg, upeer_sockaddr, upeer_addrlen, flags));\nnet/socket.c-2094-}\n--\nnet/unix/af_unix.c=3281=static int unix_open_file(struct sock *sk)\n--\nnet/unix/af_unix.c-3291-\nnet/unix/af_unix.c:3292:\treturn FD_ADD(O_CLOEXEC, dentry_open(\u0026unix_sk(sk)-\u003epath, O_PATH, current_cred()));\nnet/unix/af_unix.c-3293-}\n"
}

15/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 27869
							output: 36
							thoughts: 522

Thoughts:

**Deep Dive into Kernel File Descriptor Allocation**

Okay, here we go. Look at this – `FD_ADD`! It's defined as a macro, wrapping `__FD_ADD`, which in turn leverages both `FD_PREPARE` and `fd_publish`. Seems straightforward enough on the surface, but given where this is used, it's clearly critical.

This `FD_ADD` macro implementation is absolutely fundamental. It's used by the core system calls: `open()`, `openat()`, `openat2()`. Plus, it's touched in numerous other key areas: anonymous inodes, namespace operations, fanotify, signalfd, timerfd, message queues, memfd, sockets, and even pseudoterminals. This touches nearly everything to do with file descriptor allocation and management within the Linux kernel, not just files but pretty much anything treated as a file or accessed through a file descriptor.

Think about it: every time we see an `openat()`, `accept()`, `memfd_create()`, `timerfd_create()`, even an `epoll_create()` or `eventfd()`, `fsmount()`, they are all, without exception, going through this revised macro implementation of `FD_PREPARE` and `FD_ADD`. That's a huge architectural change.

Given this broad impact, I need to fully grok this. I'm going to start by reviewing `include/linux/file.h`, specifically lines 125 to 230, to make sure I understand all the implications and how this plays out in practice. Gotta make sure nothing is overlooked.

16/2

2026/09/19 01:38

tool

read-file

Args:

{
  "File": "include/linux/file.h",
  "FirstLine": 125,
  "LineCount": 105
}

Results:

{
  "Contents": " 125:\t\n 126:\textern void flush_delayed_fput(void);\n 127:\textern void __fput_sync(struct file *);\n 128:\t\n 129:\textern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;\n 130:\t\n 131:\t/*\n 132:\t * fd_prepare: Combined fd + file allocation cleanup class.\n 133:\t * @fd: Allocated fd\n 134:\t * @file: Allocated struct file pointer\n 135:\t *\n 136:\t * Allocates an fd and a file together. On error paths, automatically cleans\n 137:\t * up whichever resource was successfully allocated. Allows flexible file\n 138:\t * allocation with different functions per usage.\n 139:\t *\n 140:\t * Do not declare directly, use FD_PREPARE().\n 141:\t */\n 142:\tstruct fd_prepare {\n 143:\t\tint fd;\n 144:\t\tstruct file *file;\n 145:\t};\n 146:\t\n 147:\t/* Do not use directly. */\n 148:\tstatic __always_inline void __fd_prepare_cleanup(const struct fd_prepare *fdf)\n 149:\t{\n 150:\t\tif (unlikely(fdf-\u003efd \u003e= 0)) {\n 151:\t\t\tput_unused_fd(fdf-\u003efd);\n 152:\t\t\tfput(fdf-\u003efile);\n 153:\t\t}\n 154:\t}\n 155:\t\n 156:\t/* Do not use directly. */\n 157:\tstatic __always_inline struct fd_prepare __fd_prepare(int fd, struct file *file)\n 158:\t{\n 159:\t\tif (fd \u003e= 0 \u0026\u0026 IS_ERR_OR_NULL(file)) {\n 160:\t\t\tint err = file ? PTR_ERR(file) : -ENOMEM;\n 161:\t\n 162:\t\t\tput_unused_fd(fd);\n 163:\t\t\tfd = err;\n 164:\t\t\tfile = NULL;\n 165:\t\t}\n 166:\t\treturn (struct fd_prepare){ .fd = fd, .file = file };\n 167:\t}\n 168:\t\n 169:\t/*\n 170:\t * FD_PREPARE - Declare and initialize an fd_prepare instance.\n 171:\t *\n 172:\t * This allocates a new fd and only evaluates @_file_owned if the\n 173:\t * allocation succeeded. Cleanup happens when the variable goes out of\n 174:\t * scope and the guard releases whichever of the descriptor and the file\n 175:\t * was allocated. If fd_publish() was called the fd and file are\n 176:\t * published and cleanup becomes a nop.\n 177:\t *\n 178:\t * @_fdf: name of the const struct fd_prepare pointer to define\n 179:\t * @_fd_flags: flags for get_unused_fd_flags()\n 180:\t * @_file_owned: struct file to take ownership of (can be expression)\n 181:\t */\n 182:\t#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)\t\t\\\n 183:\t\tstruct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({\t\\\n 184:\t\t\tint __fd = get_unused_fd_flags(_fd_flags);\t\t\\\n 185:\t\t\t__fd_prepare(__fd, __fd \u003c 0 ? NULL : (_file_owned));\t\\\n 186:\t\t});\t\t\t\t\t\t\t\t\\\n 187:\t\tconst struct fd_prepare *const _fdf = \u0026_guard\n 188:\t\n 189:\t#define FD_PREPARE(_fdf, _fd_flags, _file_owned) \\\n 190:\t\t__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)\n 191:\t\n 192:\t/*\n 193:\t * fd_publish - Publish prepared fd and file to the fd table.\n 194:\t * @fdf: struct fd_prepare pointer defined by FD_PREPARE()\n 195:\t */\n 196:\tstatic __always_inline int fd_publish(const struct fd_prepare *fdf)\n 197:\t{\n 198:\t\t/* Callers only get a const view, the guard itself is writable. */\n 199:\t\tstruct fd_prepare *guard = (struct fd_prepare *)fdf;\n 200:\t\n 201:\t\tVFS_WARN_ON_ONCE(guard-\u003efd \u003c 0);\n 202:\t\tfd_install(guard-\u003efd, guard-\u003efile);\n 203:\t\treturn take_fd(guard-\u003efd);\n 204:\t}\n 205:\t\n 206:\t/* Do not use directly. */\n 207:\t#define __FD_ADD(_fdf, _fd_flags, _file_owned)\t\t\t\\\n 208:\t\t({\t\t\t\t\t\t\t\\\n 209:\t\t\tFD_PREPARE(_fdf, _fd_flags, _file_owned);\t\\\n 210:\t\t\t_fdf-\u003efd \u003c 0 ? _fdf-\u003efd : fd_publish(_fdf);\t\\\n 211:\t\t})\n 212:\t\n 213:\t/*\n 214:\t * FD_ADD - Allocate and install an fd and file in one step.\n 215:\t * @_fd_flags: flags for get_unused_fd_flags()\n 216:\t * @_file_owned: struct file to take ownership of\n 217:\t *\n 218:\t * Returns the allocated fd number, or negative error code on failure.\n 219:\t */\n 220:\t#define FD_ADD(_fd_flags, _file_owned) \\\n 221:\t\t__FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)\n 222:\t\n 223:\t#endif /* __LINUX_FILE_H */\n"
}

17/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 30385
							output: 27
							thoughts: 21

Thoughts:

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

**Investigating the Commit History**

Alright, so we're diving back into this code and, as always, context is key. Before I make any assumptions or start digging into the changes themselves, I want to nail down the *why* behind them. A thorough understanding starts with the original commit message. I need to understand the intent. Was it a bug fix? Feature implementation? Refactor? Knowing the rationale from the source is vital. Let's see if we can easily pull the commit log. A quick `git log` should give me the crucial context. Without that, I'm just guessing, and we both know guessing is a terrible approach, especially with critical code.

18/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "FD_PREPARE",
  "PathPrefix": "fs/"
}

Results:

{
  "Output": "fs/eventfd.c=379=static int do_eventfd(unsigned int count, int flags)\n--\nfs/eventfd.c-402-\nfs/eventfd.c:403:\tFD_PREPARE(fdf, flags,\nfs/eventfd.c-404-\t\t   anon_inode_getfile_fmode(\"[eventfd]\", \u0026eventfd_fops, ctx,\n--\nfs/eventpoll.c=2494=static int do_epoll_create(int flags)\n--\nfs/eventpoll.c-2513-\t */\nfs/eventpoll.c:2514:\tFD_PREPARE(fdf, O_RDWR | (flags \u0026 O_CLOEXEC),\nfs/eventpoll.c-2515-\t\t   anon_inode_getfile(\"[eventpoll]\", \u0026eventpoll_fops, ep,\n--\nfs/file.c=1385=int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)\n--\nfs/file.c-1392-\nfs/file.c:1393:\tFD_PREPARE(fdf, o_flags, file);\nfs/file.c-1394-\tif (fdf-\u003efd \u003c 0)\n--\nfs/namespace.c=4442=SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,\n--\nfs/namespace.c-4544-\nfs/namespace.c:4545:\tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\nfs/namespace.c-4546-\t\t   dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n--\nfs/namespace.c=5193=SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,\n--\nfs/namespace.c-5199-\nfs/namespace.c:5200:\tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\nfs/namespace.c-5201-\tif (fdf-\u003efd \u003c 0)\n--\nfs/nsfs.c=213=static long ns_ioctl(struct file *filp, unsigned int ioctl,\n--\nfs/nsfs.c-349-\nfs/nsfs.c:350:\t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\nfs/nsfs.c-351-\t\tif (fdf-\u003efd \u003c 0)\n--\nfs/xfs/xfs_handle.c=231=xfs_open_by_handle(\n--\nfs/xfs/xfs_handle.c-273-\nfs/xfs/xfs_handle.c:274:\tFD_PREPARE(fdf, 0, dentry_open(\u0026path, hreq-\u003eoflags, cred));\nfs/xfs/xfs_handle.c-275-\tif (fdf-\u003efd \u003c 0)\n"
}

19/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 31394
							output: 18
							thoughts: 1107

Thoughts:

**Analyzing the Scope and Focus of this Kernel Patch**

Okay, let's break this down. First, I need to get a handle on the breadth of this commit. I've already determined that it's touching a wide range of core subsystems: the Virtual File System (VFS), Memory Management (MM), BPF (Berkeley Packet Filter), Networking (Net), and more. This is significant; it indicates that the changes likely have broad impact and could potentially introduce subtle, widespread issues, and it modifies reachable executable code on amd64. Therefore, setting `WorthFuzzing=true` is a no-brainer.

Now, the crucial part: determining the `FocusSymbols`. The goal is to identify the most relevant functions or entry points to guide the fuzzer. I need to avoid listing common, high-frequency functions that are called almost everywhere, such as memory allocators, deallocators, or core synchronization primitives. Those would dilute the fuzzing effort. Instead, I need to pinpoint the *specific* feature logic or API entrypoints being altered.

Looking specifically at the file.h header, the changes involve these inline functions: `__fd_prepare_cleanup`, `__fd_prepare`, and `fd_publish`. Because they are static and inline, they are inlined into every call site, and won't have individual symbols. I need to look for non-ubiquitous caller functions in the .c files.

I'll start by checking the modified .c files. In `fs/eventfd.c`, I see `do_eventfd`, which is called by `__do_sys_eventfd2` and `__do_sys_eventfd`. However, that function might be ubiquitous, so let's check for other caller functions in the other files. In `fs/file.c`, I notice `receive_fd` is non-static (`EXPORT_SYMBOL_GPL(receive_fd)`). I'll need to investigate what calls `receive_fd` to see if it's a good focus.

20/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "receive_fd\\("
}

Results:

{
  "Output": "drivers/vdpa/vdpa_user/vduse_dev.c=1477=static long vduse_dev_ioctl(struct file *file, unsigned int cmd,\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c-1520-\t\t}\ndrivers/vdpa/vdpa_user/vduse_dev.c:1521:\t\tret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));\ndrivers/vdpa/vdpa_user/vduse_dev.c-1522-\t\tfput(f);\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c=1785=static long vduse_dev_compat_ioctl(struct file *file, unsigned int cmd,\n--\ndrivers/vdpa/vdpa_user/vduse_dev.c-1817-\t\t}\ndrivers/vdpa/vdpa_user/vduse_dev.c:1818:\t\tret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));\ndrivers/vdpa/vdpa_user/vduse_dev.c-1819-\t\tfput(f);\n--\nfs/file.c=1345=int replace_fd(unsigned fd, struct file *file, unsigned flags)\n--\nfs/file.c-1370-/**\nfs/file.c:1371: * receive_fd() - Install received file into file descriptor table\nfs/file.c-1372- * @file: struct file that was received from another process\n--\nfs/file.c-1384- */\nfs/file.c:1385:int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)\nfs/file.c-1386-{\n--\ninclude/linux/file.h=120=extern void fd_install(unsigned int fd, struct file *file);\ninclude/linux/file.h-121-\ninclude/linux/file.h:122:int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);\ninclude/linux/file.h-123-\n--\nio_uring/openclose.c=305=int io_install_fixed_fd(struct io_kiocb *req, unsigned int issue_flags)\n--\nio_uring/openclose.c-310-\tifi = io_kiocb_to_cmd(req, struct io_fixed_install);\nio_uring/openclose.c:311:\tret = receive_fd(req-\u003efile, NULL, ifi-\u003eo_flags);\nio_uring/openclose.c-312-\tif (ret \u003c 0)\n--\nkernel/pid.c=890=static int pidfd_getfd(struct pid *pid, int fd)\n--\nkernel/pid.c-904-\nkernel/pid.c:905:\tret = receive_fd(file, NULL, O_CLOEXEC);\nkernel/pid.c-906-\tfput(file);\n--\nkernel/seccomp.c=1124=static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_knotif *n)\n--\nkernel/seccomp.c-1133-\tif (!addfd-\u003esetfd)\nkernel/seccomp.c:1134:\t\tfd = receive_fd(addfd-\u003efile, NULL, addfd-\u003eflags);\nkernel/seccomp.c-1135-\telse\n"
}

21/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 33855
							output: 34
							thoughts: 136

Thoughts:

**Examining the File Descriptor Handling**

Okay, so `receive_fd` is a public function, not hidden away as static, and it's exported. That makes things immediately more interesting from a design perspective. Its direct use of `FD_PREPARE` with the `fdf`, `o_flags`, and `file` arguments, followed by `fd_publish`, suggests a specific workflow for handling file descriptors. I'm going to have to understand that sequence better.

Now, let's look at `scm_recv_one_fd`. It's also non-static, exposed to the world (likely through `EXPORT_SYMBOL_GPL`). I remember that function's signature. I think it lives in `net/core/scm.c`. This suggests a potential interaction point or dependency between these two functions, or possibly that this is where the *receiving* side of the file descriptor transfer is handled, with the first being the sending part. I need to dig into `net/core/scm.c` to see how it works and how it might be interacting.

22/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "scm_recv_one_fd",
  "PathPrefix": "net/core/scm.c"
}

Results:

{
  "Output": "net/core/scm.c=347=static int scm_max_fds(struct msghdr *msg)\n--\nnet/core/scm.c-353-\nnet/core/scm.c:354:int scm_recv_one_fd(struct file *f, int __user *ufd, unsigned int flags,\nnet/core/scm.c-355-\t\t    bool notrunc)\n--\nnet/core/scm.c=378=void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm, bool notrunc)\n--\nnet/core/scm.c-396-\tfor (i = 0; i \u003c fdmax; i++) {\nnet/core/scm.c:397:\t\terr = scm_recv_one_fd(scm-\u003efp-\u003efp[i], cmsg_data + i, o_flags, notrunc);\nnet/core/scm.c-398-\t\tif (err \u003c 0)\n"
}

23/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 34513
							output: 39
							thoughts: 208

Thoughts:

**Investigating Potential Attack Surfaces**

Okay, let's see, I need to start digging into this... I'm going to start by looking for exported or otherwise externally accessible functions, functions that could be entry points. The first one I'll look at is `media_request_alloc` in `drivers/media/mc/mc-request.c`. It's an exported function, `int media_request_alloc(struct media_device *mdev, int *alloc_fd)`, so that certainly warrants further investigation. Next, I'll move on to `bpf_iter_new_fd` in `kernel/bpf/bpf_iter.c`. It's a non-static function so it's also worth a look; `int bpf_iter_new_fd(struct bpf_link *link)`. Then, I'll check `bpf_token_create` in `kernel/bpf/token.c`.  `int bpf_token_create(union bpf_attr *attr)` is also a non-static function, so I'll need to understand how it's being used. Finally, I'll need to check `xfs_open_by_handle` in `fs/xfs/xfs_handle.c`, specifically around line 231 of that file, as this likely is a useful function from a filesystem perspective. I need to understand the control flow and parameters of these functions to understand if there is a vulnerability there.

24/2

2026/09/19 01:38

tool

read-file

Args:

{
  "File": "fs/xfs/xfs_handle.c",
  "FirstLine": 230,
  "LineCount": 20
}

Results:

{
  "Contents": " 230:\tint\n 231:\txfs_open_by_handle(\n 232:\t\tstruct file\t\t*parfilp,\n 233:\t\txfs_fsop_handlereq_t\t*hreq)\n 234:\t{\n 235:\t\tconst struct cred\t*cred = current_cred();\n 236:\t\tint\t\t\tpermflag;\n 237:\t\tstruct inode\t\t*inode;\n 238:\t\tstruct dentry\t\t*dentry;\n 239:\t\tfmode_t\t\t\tfmode;\n 240:\t\tstruct path\t\tpath __free(path_put) = {};\n 241:\t\n 242:\t\tif (!capable(CAP_SYS_ADMIN))\n 243:\t\t\treturn -EPERM;\n 244:\t\n 245:\t\tdentry = xfs_handlereq_to_dentry(parfilp, hreq);\n 246:\t\tif (IS_ERR(dentry))\n 247:\t\t\treturn PTR_ERR(dentry);\n 248:\t\tinode = d_inode(dentry);\n 249:\t\tpath.dentry = dentry;\n"
}

25/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 35394
							output: 36
							thoughts: 201

Thoughts:

**My Initial Thoughts on Function Visibility**

Okay, so `xfs_open_by_handle` isn't declared as `static`. That's good to know, it means it's available outside its immediate source file. Let's see... what about something in the netlink subsystem? I'll quickly check `handshake_nl_accept_doit` in `net/handshake/netlink.c`. Ah, nope, that's not static either – good, good.

Now, let's look at `drivers/gpio/gpiolib-cdev.c`. I need to understand the visibility of functions like `linehandle_create`, `linereq_create`, and `lineevent_create`. Hold on a second, are those... static? Yep, they are. Okay, those are all declared as `static`. Now, the crucial question is, who *calls* these? Given the context, it's likely the `gpio_ioctl` function. Let's dig into `drivers/gpio/gpiolib-cdev.c` and see. I need to trace the usage to understand how this module handles device requests and interactions.

26/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "linehandle_create",
  "PathPrefix": "drivers/gpio/gpiolib-cdev.c"
}

Results:

{
  "Output": "drivers/gpio/gpiolib-cdev.c=301=DEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))\ndrivers/gpio/gpiolib-cdev.c-302-\ndrivers/gpio/gpiolib-cdev.c:303:static int linehandle_create(struct gpio_device *gdev, void __user *ip)\ndrivers/gpio/gpiolib-cdev.c-304-{\n--\ndrivers/gpio/gpiolib-cdev.c=2396=static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)\n--\ndrivers/gpio/gpiolib-cdev.c-2413-\tcase GPIO_GET_LINEHANDLE_IOCTL:\ndrivers/gpio/gpiolib-cdev.c:2414:\t\treturn linehandle_create(gdev, ip);\ndrivers/gpio/gpiolib-cdev.c-2415-\tcase GPIO_GET_LINEEVENT_IOCTL:\n"
}

27/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 36156
							output: 34
							thoughts: 74

Thoughts:

Okay, let's dive into this. I need to get a handle on the syscalls that have been touched within `fs/namespace.c`. Specifically, I'm interested in any modifications to `__do_sys_fsmount` and `__do_sys_open_tree_attr`. My initial thought is to zero in on the relevant code blocks. I'll need to check the lines around 4540-4560 and 5190-5220 in `fs/namespace.c` to see what has changed or been introduced. This is where the core of the action likely resides, and where I'll find the specific logic I need to analyze.

28/2

2026/09/19 01:38

tool

read-file

Args:

{
  "File": "fs/namespace.c",
  "FirstLine": 4540,
  "LineCount": 25
}

Results:

{
  "Contents": "4540:\t\tns-\u003eroot = mnt;\n4541:\t\tns-\u003enr_mounts = 1;\n4542:\t\tmnt_add_to_ns(ns, mnt);\n4543:\t\tmntget(new_path.mnt);\n4544:\t\n4545:\t\tFD_PREPARE(fdf, (flags \u0026 FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,\n4546:\t\t\t   dentry_open(\u0026new_path, O_PATH, fc-\u003ecred));\n4547:\t\tif (fdf-\u003efd \u003c 0) {\n4548:\t\t\tdissolve_on_fput(new_path.mnt);\n4549:\t\t\treturn fdf-\u003efd;\n4550:\t\t}\n4551:\t\n4552:\t\t/*\n4553:\t\t * Attach to an apparent O_PATH fd with a note that we\n4554:\t\t * need to unmount it, not just simply put it.\n4555:\t\t */\n4556:\t\tfdf-\u003efile-\u003ef_mode |= FMODE_NEED_UNMOUNT;\n4557:\t\treturn fd_publish(fdf);\n4558:\t}\n4559:\t\n4560:\tstatic inline int vfs_move_mount(const struct path *from_path,\n4561:\t\t\t\t\t const struct path *to_path,\n4562:\t\t\t\t\t enum mnt_tree_flags_t mflags)\n4563:\t{\n4564:\t\tint ret;\n"
}

29/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 36820
							output: 34
							thoughts: 20

Thoughts:

Okay, here's my summary, taking on the persona you requested:

**Navigating the Namespace Labyrinth: Lines 5190-5220**

Alright, I'm diving into `fs/namespace.c` again. Always a tricky area, but I need to understand this specific section: lines 5190-5220. My initial thought is to zero in on what's going on here. The context is crucial. Based on my existing knowledge, I'm betting this segment deals with some aspect of how the kernel manages mount points, namespaces, or perhaps the transition between them. Probably something related to how the kernel handles the interactions between different processes’ views of the filesystem. I recall similar sections I've analyzed for previous projects – those always gave me a headache. I need to be precise, as even the smallest oversight can create huge problems in production systems. I'll read line-by-line, watching out for data structures being manipulated. Is this about cloning, unsharing, or something even more exotic? The comments, I hope, will be illuminating. I need to track data flow through any function calls, pay attention to the return values, and what kind of checks are in place. Then, I need to compare this section to similar logic within the module so I can know what this does within the broader context of the system. I also need to make sure this logic is secure. My immediate priority is to understand the *why* as much as the *how*. Then, I'll need to link this back to the bigger picture to ensure it all makes sense in the greater architecture.

30/2

2026/09/19 01:38

tool

read-file

Args:

{
  "File": "fs/namespace.c",
  "FirstLine": 5190,
  "LineCount": 30
}

Results:

{
  "Contents": "5190:\t\treturn err;\n5191:\t}\n5192:\t\n5193:\tSYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,\n5194:\t\t\tunsigned, flags, struct mount_attr __user *, uattr,\n5195:\t\t\tsize_t, usize)\n5196:\t{\n5197:\t\tif (!uattr \u0026\u0026 usize)\n5198:\t\t\treturn -EINVAL;\n5199:\t\n5200:\t\tFD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));\n5201:\t\tif (fdf-\u003efd \u003c 0)\n5202:\t\t\treturn fdf-\u003efd;\n5203:\t\n5204:\t\tif (uattr) {\n5205:\t\t\tstruct mount_kattr kattr = {};\n5206:\t\t\tstruct file *file = fdf-\u003efile;\n5207:\t\t\tint ret;\n5208:\t\n5209:\t\t\tif (flags \u0026 OPEN_TREE_CLONE)\n5210:\t\t\t\tkattr.kflags = MOUNT_KATTR_IDMAP_REPLACE;\n5211:\t\t\tif (flags \u0026 AT_RECURSIVE)\n5212:\t\t\t\tkattr.kflags |= MOUNT_KATTR_RECURSE;\n5213:\t\n5214:\t\t\tret = wants_mount_setattr(uattr, usize, \u0026kattr);\n5215:\t\t\tif (ret \u003e 0) {\n5216:\t\t\t\tret = do_mount_setattr(\u0026file-\u003ef_path, \u0026kattr);\n5217:\t\t\t\tfinish_mount_kattr(\u0026kattr);\n5218:\t\t\t}\n5219:\t\t\tif (ret)\n"
}

31/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 37685
							output: 31
							thoughts: 41

Thoughts:

Here's my take on the thought process, as requested:

**Diving into `io_uring/mock_file.c`**

Okay, time to get my hands dirty. I'm going to start by examining `io_uring/mock_file.c`. My immediate focus is the `io_create_mock_file` function. I need to understand its definition and, crucially, how it's actually invoked within the broader context of this `io_uring` implementation. That will give me insights into its purpose and role within the overall system.

32/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "io_create_mock_file",
  "PathPrefix": "io_uring/"
}

Results:

{
  "Output": "io_uring/mock_file.c=197=static const struct file_operations io_mock_poll_fops = {\n--\nio_uring/mock_file.c-209-\nio_uring/mock_file.c:210:static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flags)\nio_uring/mock_file.c-211-{\n--\nio_uring/mock_file.c=304=static int iou_mock_mgr_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)\n--\nio_uring/mock_file.c-312-\tcase IORING_MOCK_MGR_CMD_CREATE:\nio_uring/mock_file.c:313:\t\treturn io_create_mock_file(cmd, issue_flags);\nio_uring/mock_file.c-314-\t}\n"
}

33/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 38116
							output: 36
							thoughts: 35

Thoughts:

Okay, let's dive in.
**Diving into `ntsync.c`**

Alright, time to get to it. I'm going to start by taking a look at `ntsync.c`. I need to figure out how this is implemented. Specifically, I'm interested in understanding the function `ntsync_obj_get_fd`. Let's navigate to the relevant directory, which should be `drivers/misc/ntsync.c`. That should give me a solid starting point for my analysis. Let's see what we can uncover.

34/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "ntsync_obj_get_fd",
  "PathPrefix": "drivers/misc/ntsync.c"
}

Results:

{
  "Output": "drivers/misc/ntsync.c=704=static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev,\n--\ndrivers/misc/ntsync.c-722-\ndrivers/misc/ntsync.c:723:static int ntsync_obj_get_fd(struct ntsync_obj *obj)\ndrivers/misc/ntsync.c-724-{\n--\ndrivers/misc/ntsync.c=733=static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)\n--\ndrivers/misc/ntsync.c-749-\tsem-\u003eu.sem.max = args.max;\ndrivers/misc/ntsync.c:750:\tfd = ntsync_obj_get_fd(sem);\ndrivers/misc/ntsync.c-751-\tif (fd \u003c 0)\n--\ndrivers/misc/ntsync.c=757=static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp)\n--\ndrivers/misc/ntsync.c-773-\tmutex-\u003eu.mutex.owner = args.owner;\ndrivers/misc/ntsync.c:774:\tfd = ntsync_obj_get_fd(mutex);\ndrivers/misc/ntsync.c-775-\tif (fd \u003c 0)\n--\ndrivers/misc/ntsync.c=781=static int ntsync_create_event(struct ntsync_device *dev, void __user *argp)\n--\ndrivers/misc/ntsync.c-794-\tevent-\u003eu.event.signaled = args.signaled;\ndrivers/misc/ntsync.c:795:\tfd = ntsync_obj_get_fd(event);\ndrivers/misc/ntsync.c-796-\tif (fd \u003c 0)\n"
}

35/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 38790
							output: 32
							thoughts: 38

Thoughts:

Here's my take on those thoughts:

**Considering `userfaultfd` Implementation**

Okay, so I'm thinking about `userfaultfd`. Specifically, I need to understand its core implementation. Where's the entry point? Right, it's `new_userfaultfd` in `mm/userfaultfd.c`. That function is probably where the magic starts. Time to dive into that file and see how this thing is actually put together. I need to refresh my memory on the data structures and control flow within this part of the memory management subsystem.

36/2

2026/09/19 01:38

tool

grepper

Args:

{
  "Expression": "new_userfaultfd",
  "PathPrefix": "mm/userfaultfd.c"
}

Results:

{
  "Output": "mm/userfaultfd.c=4773=static void init_once_userfaultfd_ctx(void *mem)\n--\nmm/userfaultfd.c-4783-\nmm/userfaultfd.c:4784:static int new_userfaultfd(int flags)\nmm/userfaultfd.c-4785-{\n--\nmm/userfaultfd.c=4839=SYSCALL_DEFINE1(userfaultfd, int, flags)\n--\nmm/userfaultfd.c-4843-\nmm/userfaultfd.c:4844:\treturn new_userfaultfd(flags);\nmm/userfaultfd.c-4845-}\n--\nmm/userfaultfd.c=4847=static long userfaultfd_dev_ioctl(struct file *file, unsigned int cmd, unsigned long flags)\n--\nmm/userfaultfd.c-4851-\nmm/userfaultfd.c:4852:\treturn new_userfaultfd(flags);\nmm/userfaultfd.c-4853-}\n"
}

37/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 39255
							output: 39
							thoughts: 41

Thoughts:

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

**Analyzing the KCM IOCTL Implementation**

Okay, time to dive into this `kcm_ioctl` situation. My first move is to go straight to the source. Specifically, I need to zero in on `net/kcm/kcmsock.c`. I'm interested in the `kcm_ioctl` function itself, so I'll be looking at lines 1570 through 1600. That section should give me the core logic for how the IOCTL commands are handled within the KCM framework. I'm hoping to quickly identify the specific IOCTLs supported and understand the corresponding actions. My goal here is to establish the context for this specific area and identify any potential problem points.

38/2

2026/09/19 01:38

tool

read-file

Args:

{
  "File": "net/kcm/kcmsock.c",
  "FirstLine": 1570,
  "LineCount": 35
}

Results:

{
  "Contents": "1570:\t\t\tstruct kcm_unattach info;\n1571:\t\n1572:\t\t\tif (copy_from_user(\u0026info, (void __user *)arg, sizeof(info)))\n1573:\t\t\t\treturn -EFAULT;\n1574:\t\n1575:\t\t\terr = kcm_unattach_ioctl(sock, \u0026info);\n1576:\t\n1577:\t\t\tbreak;\n1578:\t\t}\n1579:\t\tcase SIOCKCMCLONE: {\n1580:\t\t\tstruct kcm_clone info;\n1581:\t\n1582:\t\t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n1583:\t\t\tif (fdf-\u003efd \u003c 0)\n1584:\t\t\t\treturn fdf-\u003efd;\n1585:\t\n1586:\t\t\tinfo.fd = fdf-\u003efd;\n1587:\t\t\tif (copy_to_user((void __user *)arg, \u0026info, sizeof(info)))\n1588:\t\t\t\treturn -EFAULT;\n1589:\t\n1590:\t\t\tfd_publish(fdf);\n1591:\t\t\terr = 0;\n1592:\t\t\tbreak;\n1593:\t\t}\n1594:\t\tdefault:\n1595:\t\t\terr = -ENOIOCTLCMD;\n1596:\t\t\tbreak;\n1597:\t\t}\n1598:\t\n1599:\t\treturn err;\n1600:\t}\n1601:\t\n1602:\tstatic void release_mux(struct kcm_mux *mux)\n1603:\t{\n1604:\t\tstruct kcm_net *knet = mux-\u003eknet;\n"
}

39/2

2026/09/19 01:38

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 39958
							output: 34
							thoughts: 197

Thoughts:

**My Analysis of the KCM and Namespace IOCTL Handlers**

Okay, so I'm looking at `kcm_ioctl`. Right off the bat, I see this is the entry point for handling `ioctl` calls specifically for KCM sockets. The key thing here is the `kcm_clone(sock)` function. We're cloning the socket, and that's being passed to `FD_PREPARE`. `FD_PREPARE` is then going to set up a file descriptor, and if that operation fails, we're returning the negative error code directly. We assign the file descriptor we got back from `FD_PREPARE` to the `info.fd` variable. This will be the fd we pass back to userspace, it's pretty standard so far.

Now, this `copy_to_user` call is important. We're copying that `info` struct, which contains the new file descriptor, back to the user-space buffer pointed to by `arg`. *If* that `copy_to_user` fails with `-EFAULT`, the scope will exit. That means the resources allocated for the file descriptor are cleaned up. We don't have to worry about a resource leak in that case. The cleanup must be handled implicitly because the `fdf` structure is declared locally.

Alright, now I'll switch gears and shift my focus to `ns_ioctl` within `fs/nsfs.c`. I'll need to go to lines 340-370 to properly see what's going on there. I'm sure there's something interesting there, related to namespace management!

40/2

2026/09/19 01:39

tool

read-file

Args:

{
  "File": "fs/nsfs.c",
  "FirstLine": 340,
  "LineCount": 35
}

Results:

{
  "Contents": " 340:\t\t\tmnt_ns = get_sequential_mnt_ns(to_mnt_ns(ns), previous);\n 341:\t\t\tif (IS_ERR(mnt_ns))\n 342:\t\t\t\treturn PTR_ERR(mnt_ns);\n 343:\t\n 344:\t\t\tns = to_ns_common(mnt_ns);\n 345:\t\t\t/* Transfer ownership of @mnt_ns reference to @path. */\n 346:\t\t\tret = path_from_stashed(\u0026ns-\u003estashed, nsfs_mnt, ns, \u0026path);\n 347:\t\t\tif (ret)\n 348:\t\t\t\treturn ret;\n 349:\t\n 350:\t\t\tFD_PREPARE(fdf, O_CLOEXEC, dentry_open(\u0026path, O_RDONLY, current_cred()));\n 351:\t\t\tif (fdf-\u003efd \u003c 0)\n 352:\t\t\t\treturn fdf-\u003efd;\n 353:\t\t\t/*\n 354:\t\t\t * If @uinfo is passed return all information about the\n 355:\t\t\t * mount namespace as well.\n 356:\t\t\t */\n 357:\t\t\tret = copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, \u0026kinfo);\n 358:\t\t\tif (ret)\n 359:\t\t\t\treturn ret;\n 360:\t\t\tret = fd_publish(fdf);\n 361:\t\t\tbreak;\n 362:\t\t}\n 363:\t\tdefault:\n 364:\t\t\tret = -ENOTTY;\n 365:\t\t}\n 366:\t\n 367:\t\treturn ret;\n 368:\t}\n 369:\t\n 370:\tint ns_get_name(char *buf, size_t size, struct task_struct *task,\n 371:\t\t\t\tconst struct proc_ns_operations *ns_ops)\n 372:\t{\n 373:\t\tstruct ns_common *ns;\n 374:\t\tint res = -ENOENT;\n"
}

41/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 41075
							output: 29
							thoughts: 344

Thoughts:

**Analyzing `ns_ioctl` and Relevant Kernel Configurations**

Okay, let's break this down. I'm looking at `fs/nsfs.c: ns_ioctl`, specifically the `FD_PREPARE` usage with `O_CLOEXEC` and the subsequent error handling. The function calls `dentry_open`, and then checks the file descriptor `fdf->fd`. I see the `copy_ns_info_to_user` function, which makes sense for namespace information transfer. Finally, `fd_publish` is called.

Now, I need to check the relevant Kconfig options to understand the dependencies and build configurations. Let's make sure I understand the context for these features.

I need to confirm if these configurations are enabled:

*   `userfaultfd`: USERFAULTFD
*   `eventpoll`: EPOLL
*   `eventfd`: EVENTFD
*   `fs/file.c`: This is core VFS; it's always compiled. That's good.
*   `bpf_iter_new_fd`: BPF\_SYSCALL
*   `bpf_token_create`: BPF\_SYSCALL
*   `kcm`: KCM
*   `ntsync`: NTSYNC
*   `gpiolib-cdev`: GPIOLIB (and GPIO\_CDEV)
*   `media_request_alloc`: This requires MEDIA\_SUPPORT and MEDIA\_CONTROLLER.
*   `open_tree_attr` / `fsmount`: Part of core VFS, so should be built-in.
*   `receive_fd` / `scm_recv_one_fd`: Core VFS/NET, so likely built-in.

I'll use grepper to search the Kconfig files for these features to confirm the build configuration. That should give me the full picture.

42/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "config NTSYNC",
  "PathPrefix": "drivers/misc/"
}

Results:

{
  "Output": "drivers/misc/Kconfig=441=config OPEN_DICE\n--\ndrivers/misc/Kconfig-453-\ndrivers/misc/Kconfig:454:config NTSYNC\ndrivers/misc/Kconfig-455-\ttristate \"NT synchronization primitive emulation\"\n"
}

43/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 41936
							output: 29
							thoughts: 27

Thoughts:

**Investigating the `io_uring/mock_file.c` Implementation**

Okay, so I need to understand the configuration that enables `mock_file.c` within the `io_uring` framework. I'm going to start by going straight into the code. Time to dig into `io_uring/mock_file.c` and figure out the conditionals. The goal is to identify what settings or flags must be set for this module to be active. I'm looking for the defining factors here.

44/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "mock_file\\.o",
  "PathPrefix": "io_uring/"
}

Results:

{
  "Output": "io_uring/Makefile=25=obj-$(CONFIG_PROC_FS) += fdinfo.o\nio_uring/Makefile:26:obj-$(CONFIG_IO_URING_MOCK_FILE) += mock_file.o\nio_uring/Makefile-27-obj-$(CONFIG_IO_URING_BPF) += bpf_filter.o\n"
}

45/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 42196
							output: 33
							thoughts: 23

Thoughts:

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

**IO_URING_MOCK_FILE Hunt**

Okay, so `CONFIG_IO_URING_MOCK_FILE`... that rings a bell.  I need to quickly figure out where this macro is actually defined in the kernel source.  I'm assuming it's part of the iouring subsystem, given the naming convention, but let's not make assumptions.  Time to fire up the grep, find, or whatever tool is quickest to locate the definition. Understanding its scope and purpose is critical before I dive into any code that *uses* it.  Is it a build option?  A conditional compilation flag?  Or something more internal to a specific part of the mock file support?  Knowing its exact definition will dictate my next step, whether I'm debugging, configuring, or trying to understand a particular feature. Gotta see the implementation first.

46/2

2026/09/19 01:39

tool

grepper

Error:

no matches

Args:

{
  "Expression": "config IO_URING_MOCK_FILE",
  "PathPrefix": "io_uring/"
}

Results:

{
  "error": "no matches"
}

47/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 42462
							output: 22
							thoughts: 21

Thoughts:

Okay, here's my summarized thought process, presented as if I were thinking it:

**Digging into IO_URING_MOCK_FILE Configuration**

Alright, time to get to work. I need to understand how `IO_URING_MOCK_FILE` is configured within this kernel tree. My immediate instinct is to leverage `grep`. It's the most efficient way to quickly search through the Kconfig files, which are, of course, where these build-time options are defined. So, I need to use `grep` across the entire source tree, targeting all the relevant Kconfig files. This should give me the configuration context I need – where it's defined, any dependencies, any default values, and so on. This should give me the information necessary to know about this option.

48/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "IO_URING_MOCK_FILE"
}

Results:

{
  "Output": "include/uapi/linux/io_uring/mock_file.h:1:#ifndef LINUX_IO_URING_MOCK_FILE_H\ninclude/uapi/linux/io_uring/mock_file.h:2:#define LINUX_IO_URING_MOCK_FILE_H\ninclude/uapi/linux/io_uring/mock_file.h-3-\n--\ninit/Kconfig=1969=config GCOV_PROFILE_URING\n--\ninit/Kconfig-1981-\ninit/Kconfig:1982:config IO_URING_MOCK_FILE\ninit/Kconfig-1983-\ttristate \"Enable io_uring mock files (Experimental)\" if EXPERT\n--\nio_uring/Makefile=25=obj-$(CONFIG_PROC_FS) += fdinfo.o\nio_uring/Makefile:26:obj-$(CONFIG_IO_URING_MOCK_FILE) += mock_file.o\nio_uring/Makefile-27-obj-$(CONFIG_IO_URING_BPF) += bpf_filter.o\n"
}

49/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 42940
							output: 33
							thoughts: 31

Thoughts:

Here's my take:

**Investigating IO_URING_MOCK_FILE Dependencies in the Kernel Configuration**

Okay, so I need to quickly figure out the dependencies for `IO_URING_MOCK_FILE`. My instinct is to head straight to `init/Kconfig` – that's where the heart of kernel configuration lives. I'm pretty sure it'll be around line 1982, maybe a few lines above or below, but that's a good starting point to locate the relevant menu entry. I need to understand what other options are required or might influence the visibility and selection of `IO_URING_MOCK_FILE`. Is it contingent on a specific architecture? Does it require some broader IO_URING configuration to be enabled first? I have to consider the potential for dependencies. I want a clear picture of its integration. I'll get the details on its relationships and any conditional logic tied to that configuration.

50/2

2026/09/19 01:39

tool

read-file

Args:

{
  "File": "init/Kconfig",
  "FirstLine": 1980,
  "LineCount": 15
}

Results:

{
  "Contents": "1980:\t\t  specific test purposes.\n1981:\t\n1982:\tconfig IO_URING_MOCK_FILE\n1983:\t\ttristate \"Enable io_uring mock files (Experimental)\" if EXPERT\n1984:\t\tdefault n\n1985:\t\tdepends on IO_URING\n1986:\t\thelp\n1987:\t\t  Enable mock files for io_uring subsystem testing. The ABI might\n1988:\t\t  still change, so it's still experimental and should only be enabled\n1989:\t\t  for specific test purposes.\n1990:\t\n1991:\t\t  If unsure, say N.\n1992:\t\n1993:\tconfig ADVISE_SYSCALLS\n1994:\t\tbool \"Enable madvise/fadvise syscalls\" if EXPERT\n"
}

51/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 43424
							output: 29
							thoughts: 19

Thoughts:

Here's my thought process, as it is:

**Checking `GPIO_CDEV` in `drivers/gpio/Kconfig`**

Okay, time to get started. My first step is to quickly confirm the presence and nature of `GPIO_CDEV`. I need to ensure it's defined within the core GPIO driver configuration. I'm going to navigate directly to `drivers/gpio/Kconfig` and verify its presence there. Knowing this Kconfig file inside and out, I already have a mental map of where things are likely located. I expect to find a definition, probably with associated help text. I want to understand if it's dependent on any other configurations, and the general purpose of this GPIO character device that I am configuring. Essentially, I'm checking the Kconfig to understand the "what" and "why" behind `GPIO_CDEV` before I dig deeper into its implementation.

52/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "config GPIO_CDEV",
  "PathPrefix": "drivers/gpio/"
}

Results:

{
  "Output": "drivers/gpio/Kconfig=75=config GPIO_SYSFS_LEGACY\n--\ndrivers/gpio/Kconfig-82-\ndrivers/gpio/Kconfig:83:config GPIO_CDEV\ndrivers/gpio/Kconfig-84-\tbool \"Character device (/dev/gpiochipN) support\" if EXPERT\n--\ndrivers/gpio/Kconfig-95-\ndrivers/gpio/Kconfig:96:config GPIO_CDEV_V1\ndrivers/gpio/Kconfig-97-\tbool \"Support GPIO ABI Version 1\"\n"
}

53/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 43804
							output: 25
							thoughts: 60

Thoughts:

Here's my thought process, as it stands:

**Reviewing GPIO Device Driver Implementation Details**

Okay, so I'm diving into the GPIO driver code again. First, I need to make sure I'm fully up to speed with how the different versions are handled. Let's start by comparing `GPIO_CDEV_V1` and the current `GPIO_CDEV`. I know those are the key interfaces, and the versioning is important for compatibility. I recall `linehandle_create` and `lineevent_create` are specific to the `GPIO_CDEV_V1` implementation, so I'll need to double-check their interaction points within that version. This is critical for assessing how the old and new methods are handled. Next, I'll shift gears and check the `net/handshake/Kconfig` file. I need to see how the GPIO driver is being configured relative to the net handshake protocols. This could give insight into timing dependency and interoperability.

54/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "HANDSHAKE",
  "PathPrefix": "net/"
}

Results:

{
  "Output": "\nFull output is too long, showing 500 out of 508 lines.\nUse more precise expression if possible.\n\nnet/Kconfig=92=source \"net/xdp/Kconfig\"\nnet/Kconfig-93-\nnet/Kconfig:94:config NET_HANDSHAKE\nnet/Kconfig-95-\tbool\n--\nnet/Kconfig-98-\nnet/Kconfig:99:config NET_HANDSHAKE_KUNIT_TEST\nnet/Kconfig-100-\ttristate \"KUnit tests for the handshake upcall mechanism\" if !KUNIT_ALL_TESTS\n--\nnet/Makefile=75=obj-$(CONFIG_MCTP)\t\t+= mctp/\nnet/Makefile:76:obj-$(CONFIG_NET_HANDSHAKE)\t+= handshake/\nnet/Makefile-77-obj-$(CONFIG_NET_SHAPER)\t+= shaper/\n--\nnet/bluetooth/hidp/core.c=243=static int hidp_get_raw_report(struct hid_device *hid,\n--\nnet/bluetooth/hidp/core.c-312-\t} else {\nnet/bluetooth/hidp/core.c:313:\t\t/* Device returned a HANDSHAKE, indicating  protocol error. */\nnet/bluetooth/hidp/core.c-314-\t\tlen = -EIO;\n--\nnet/bluetooth/hidp/core.c=459=static void hidp_process_handshake(struct hidp_session *session,\n--\nnet/bluetooth/hidp/core.c-492-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:493:\t\t\tHIDP_TRANS_HANDSHAKE | HIDP_HSHK_ERR_INVALID_PARAMETER, NULL, 0);\nnet/bluetooth/hidp/core.c-494-\t\tbreak;\n--\nnet/bluetooth/hidp/core.c=517=static int hidp_process_data(struct hidp_session *session, struct sk_buff *skb,\n--\nnet/bluetooth/hidp/core.c-541-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:542:\t\t\tHIDP_TRANS_HANDSHAKE | HIDP_HSHK_ERR_INVALID_PARAMETER, NULL, 0);\nnet/bluetooth/hidp/core.c-543-\t}\n--\nnet/bluetooth/hidp/core.c=561=static void hidp_recv_ctrl_frame(struct hidp_session *session,\n--\nnet/bluetooth/hidp/core.c-577-\tswitch (type) {\nnet/bluetooth/hidp/core.c:578:\tcase HIDP_TRANS_HANDSHAKE:\nnet/bluetooth/hidp/core.c-579-\t\thidp_process_handshake(session, param);\n--\nnet/bluetooth/hidp/core.c-591-\t\thidp_send_ctrl_message(session,\nnet/bluetooth/hidp/core.c:592:\t\t\tHIDP_TRANS_HANDSHAKE | HIDP_HSHK_ERR_UNSUPPORTED_REQUEST, NULL, 0);\nnet/bluetooth/hidp/core.c-593-\t\tbreak;\n--\nnet/bluetooth/hidp/hidp.h-33-/* HIDP transaction types */\nnet/bluetooth/hidp/hidp.h:34:#define HIDP_TRANS_HANDSHAKE\t\t\t0x00\nnet/bluetooth/hidp/hidp.h-35-#define HIDP_TRANS_HID_CONTROL\t\t\t0x10\n--\nnet/handshake/.kunitconfig=9=CONFIG_SUNRPC=y\nnet/handshake/.kunitconfig:10:CONFIG_NET_HANDSHAKE=y\nnet/handshake/.kunitconfig:11:CONFIG_NET_HANDSHAKE_KUNIT_TEST=y\n--\nnet/handshake/Makefile-2-#\nnet/handshake/Makefile:3:# Makefile for the Generic HANDSHAKE service\nnet/handshake/Makefile-4-#\n--\nnet/handshake/Makefile=11=handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o\nnet/handshake/Makefile-12-\nnet/handshake/Makefile:13:obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o\n--\nnet/handshake/genl.c-14-\nnet/handshake/genl.c:15:/* HANDSHAKE_CMD_ACCEPT - do */\nnet/handshake/genl.c:16:static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HANDLER_CLASS + 1] = {\nnet/handshake/genl.c:17:\t[HANDSHAKE_A_ACCEPT_HANDLER_CLASS] = NLA_POLICY_MAX(NLA_U32, 2),\nnet/handshake/genl.c-18-};\nnet/handshake/genl.c-19-\nnet/handshake/genl.c:20:/* HANDSHAKE_CMD_DONE - do */\nnet/handshake/genl.c:21:static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {\nnet/handshake/genl.c:22:\t[HANDSHAKE_A_DONE_STATUS] = NLA_POLICY_MAX(NLA_U32, MAX_ERRNO),\nnet/handshake/genl.c:23:\t[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },\nnet/handshake/genl.c:24:\t[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },\nnet/handshake/genl.c-25-};\n--\nnet/handshake/genl.c=28=static const struct genl_split_ops handshake_nl_ops[] = {\nnet/handshake/genl.c-29-\t{\nnet/handshake/genl.c:30:\t\t.cmd\t\t= HANDSHAKE_CMD_ACCEPT,\nnet/handshake/genl.c-31-\t\t.doit\t\t= handshake_nl_accept_doit,\nnet/handshake/genl.c-32-\t\t.policy\t\t= handshake_accept_nl_policy,\nnet/handshake/genl.c:33:\t\t.maxattr\t= HANDSHAKE_A_ACCEPT_HANDLER_CLASS,\nnet/handshake/genl.c-34-\t\t.flags\t\t= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,\n--\nnet/handshake/genl.c-36-\t{\nnet/handshake/genl.c:37:\t\t.cmd\t\t= HANDSHAKE_CMD_DONE,\nnet/handshake/genl.c-38-\t\t.doit\t\t= handshake_nl_done_doit,\nnet/handshake/genl.c-39-\t\t.policy\t\t= handshake_done_nl_policy,\nnet/handshake/genl.c:40:\t\t.maxattr\t= HANDSHAKE_A_DONE_REMOTE_AUTH,\nnet/handshake/genl.c-41-\t\t.flags\t\t= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,\n--\nnet/handshake/genl.c=45=static const struct genl_multicast_group handshake_nl_mcgrps[] = {\nnet/handshake/genl.c:46:\t[HANDSHAKE_NLGRP_NONE] = { \"none\", },\nnet/handshake/genl.c:47:\t[HANDSHAKE_NLGRP_TLSHD] = { \"tlshd\", },\nnet/handshake/genl.c-48-};\n--\nnet/handshake/genl.c=50=struct genl_family handshake_nl_family __ro_after_init = {\nnet/handshake/genl.c:51:\t.name\t\t= HANDSHAKE_FAMILY_NAME,\nnet/handshake/genl.c:52:\t.version\t= HANDSHAKE_FAMILY_VERSION,\nnet/handshake/genl.c-53-\t.netnsok\t= true,\n--\nnet/handshake/genl.h-6-\nnet/handshake/genl.h:7:#ifndef _LINUX_HANDSHAKE_GEN_H\nnet/handshake/genl.h:8:#define _LINUX_HANDSHAKE_GEN_H\nnet/handshake/genl.h-9-\n--\nnet/handshake/genl.h=19=enum {\nnet/handshake/genl.h:20:\tHANDSHAKE_NLGRP_NONE,\nnet/handshake/genl.h:21:\tHANDSHAKE_NLGRP_TLSHD,\nnet/handshake/genl.h-22-};\n--\nnet/handshake/genl.h=24=extern struct genl_family handshake_nl_family;\nnet/handshake/genl.h-25-\nnet/handshake/genl.h:26:#endif /* _LINUX_HANDSHAKE_GEN_H */\n--\nnet/handshake/handshake-test.c=40=static struct handshake_proto handshake_req_alloc_proto_2 = {\nnet/handshake/handshake-test.c:41:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_NONE,\nnet/handshake/handshake-test.c-42-};\n--\nnet/handshake/handshake-test.c=44=static struct handshake_proto handshake_req_alloc_proto_3 = {\nnet/handshake/handshake-test.c:45:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_MAX,\nnet/handshake/handshake-test.c-46-};\n--\nnet/handshake/handshake-test.c=48=static struct handshake_proto handshake_req_alloc_proto_4 = {\nnet/handshake/handshake-test.c:49:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-50-};\n--\nnet/handshake/handshake-test.c=52=static struct handshake_proto handshake_req_alloc_proto_5 = {\nnet/handshake/handshake-test.c:53:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-54-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake-test.c=57=static struct handshake_proto handshake_req_alloc_proto_6 = {\nnet/handshake/handshake-test.c:58:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-59-\t.hp_privsize\t\t= UINT_MAX,\n--\nnet/handshake/handshake-test.c=64=static struct handshake_proto handshake_req_alloc_proto_good = {\nnet/handshake/handshake-test.c:65:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-66-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake-test.c=362=static void handshake_req_cancel_test2(struct kunit *test)\n--\nnet/handshake/handshake-test.c-394-\t/* Pretend to accept this request */\nnet/handshake/handshake-test.c:395:\tnext = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);\nnet/handshake/handshake-test.c-396-\tKUNIT_ASSERT_PTR_EQ(test, req, next);\n--\nnet/handshake/handshake-test.c=412=static void handshake_req_cancel_test3(struct kunit *test)\n--\nnet/handshake/handshake-test.c-444-\t/* Pretend to accept this request */\nnet/handshake/handshake-test.c:445:\tnext = handshake_req_next(hn, HANDSHAKE_HANDLER_CLASS_TLSHD);\nnet/handshake/handshake-test.c-446-\tKUNIT_ASSERT_PTR_EQ(test, req, next);\n--\nnet/handshake/handshake-test.c=473=static struct handshake_proto handshake_req_alloc_proto_destroy = {\nnet/handshake/handshake-test.c:474:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/handshake-test.c-475-\t.hp_accept\t\t= test_accept_func,\n--\nnet/handshake/handshake.h-9-\nnet/handshake/handshake.h:10:#ifndef _INTERNAL_HANDSHAKE_H\nnet/handshake/handshake.h:11:#define _INTERNAL_HANDSHAKE_H\nnet/handshake/handshake.h-12-\n--\nnet/handshake/handshake.h=23=enum hn_flags_bits {\nnet/handshake/handshake.h:24:\tHANDSHAKE_F_NET_DRAINING,\nnet/handshake/handshake.h-25-};\n--\nnet/handshake/handshake.h=44=enum hr_flags_bits {\nnet/handshake/handshake.h:45:\tHANDSHAKE_F_REQ_COMPLETED,\nnet/handshake/handshake.h:46:\tHANDSHAKE_F_REQ_SESSION,\nnet/handshake/handshake.h-47-};\n--\nnet/handshake/handshake.h=67=enum hp_flags_bits {\nnet/handshake/handshake.h:68:\tHANDSHAKE_F_PROTO_NOTIFY,\nnet/handshake/handshake.h-69-};\n--\nnet/handshake/handshake.h=93=bool handshake_req_cancel(struct sock *sk);\nnet/handshake/handshake.h-94-\nnet/handshake/handshake.h:95:#endif /* _INTERNAL_HANDSHAKE_H */\n--\nnet/handshake/netlink.c=37=int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,\n--\nnet/handshake/netlink.c-43-\t/* Disable notifications during unit testing */\nnet/handshake/netlink.c:44:\tif (!test_bit(HANDSHAKE_F_PROTO_NOTIFY, \u0026proto-\u003ehp_flags))\nnet/handshake/netlink.c-45-\t\treturn 0;\n--\nnet/handshake/netlink.c-55-\thdr = genlmsg_put(msg, 0, 0, \u0026handshake_nl_family, 0,\nnet/handshake/netlink.c:56:\t\t\t  HANDSHAKE_CMD_READY);\nnet/handshake/netlink.c-57-\tif (!hdr)\n--\nnet/handshake/netlink.c-59-\nnet/handshake/netlink.c:60:\tif (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_HANDLER_CLASS,\nnet/handshake/netlink.c-61-\t\t\tproto-\u003ehp_handler_class) \u003c 0) {\n--\nnet/handshake/netlink.c=90=int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/handshake/netlink.c-101-\terr = -EINVAL;\nnet/handshake/netlink.c:102:\tif (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_ACCEPT_HANDLER_CLASS))\nnet/handshake/netlink.c-103-\t\tgoto out_status;\nnet/handshake/netlink.c:104:\tclass = nla_get_u32(info-\u003eattrs[HANDSHAKE_A_ACCEPT_HANDLER_CLASS]);\nnet/handshake/netlink.c-105-\n--\nnet/handshake/netlink.c=133=int handshake_nl_done_doit(struct sk_buff *skb, struct genl_info *info)\n--\nnet/handshake/netlink.c-139-\nnet/handshake/netlink.c:140:\tif (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_DONE_SOCKFD))\nnet/handshake/netlink.c-141-\t\treturn -EINVAL;\nnet/handshake/netlink.c:142:\tfd = nla_get_s32(info-\u003eattrs[HANDSHAKE_A_DONE_SOCKFD]);\nnet/handshake/netlink.c-143-\n--\nnet/handshake/netlink.c-158-\tstatus = -EIO;\nnet/handshake/netlink.c:159:\tif (info-\u003eattrs[HANDSHAKE_A_DONE_STATUS])\nnet/handshake/netlink.c:160:\t\tstatus = -(int)nla_get_u32(info-\u003eattrs[HANDSHAKE_A_DONE_STATUS]);\nnet/handshake/netlink.c-161-\n--\nnet/handshake/netlink.c=191=static void __net_exit handshake_net_exit(struct net *net)\n--\nnet/handshake/netlink.c-202-\tspin_lock_bh(\u0026hn-\u003ehn_lock);\nnet/handshake/netlink.c:203:\tset_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags);\nnet/handshake/netlink.c-204-\tlist_splice_init(\u0026hn-\u003ehn_requests, \u0026requests);\n--\nnet/handshake/request.c=109=struct handshake_req *handshake_req_alloc(const struct handshake_proto *proto,\n--\nnet/handshake/request.c-115-\t\treturn NULL;\nnet/handshake/request.c:116:\tif (proto-\u003ehp_handler_class \u003c= HANDSHAKE_HANDLER_CLASS_NONE)\nnet/handshake/request.c-117-\t\treturn NULL;\nnet/handshake/request.c:118:\tif (proto-\u003ehp_handler_class \u003e= HANDSHAKE_HANDLER_CLASS_MAX)\nnet/handshake/request.c-119-\t\treturn NULL;\n--\nnet/handshake/request.c=169=static bool remove_pending(struct handshake_net *hn, struct handshake_req *req)\n--\nnet/handshake/request.c-173-\tspin_lock_bh(\u0026hn-\u003ehn_lock);\nnet/handshake/request.c:174:\tif (!test_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags) \u0026\u0026\nnet/handshake/request.c-175-\t    !list_empty(\u0026req-\u003ehr_list)) {\n--\nnet/handshake/request.c=251=int handshake_req_submit(struct socket *sock, struct handshake_req *req,\n--\nnet/handshake/request.c-290-\tret = -EOPNOTSUPP;\nnet/handshake/request.c:291:\tif (test_bit(HANDSHAKE_F_NET_DRAINING, \u0026hn-\u003ehn_flags))\nnet/handshake/request.c-292-\t\tgoto out_unlock;\n--\nnet/handshake/request.c-313-\ttrace_handshake_submit_err(net, req, req-\u003ehr_sk, ret);\nnet/handshake/request.c:314:\tif (!test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-315-\t\t/* Restore original destructor so socket teardown still runs. */\n--\nnet/handshake/request.c=324=void handshake_complete(struct handshake_req *req, int status,\n--\nnet/handshake/request.c-329-\nnet/handshake/request.c:330:\tif (!test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-331-\t\tstruct file *file = req-\u003ehr_file;\n--\nnet/handshake/request.c=352=bool handshake_req_cancel(struct sock *sk)\n--\nnet/handshake/request.c-367-\t\t/* Request hadn't been accepted - mark cancelled */\nnet/handshake/request.c:368:\t\tif (test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-369-\t\t\ttrace_handshake_cancel_busy(net, req, sk);\n--\nnet/handshake/request.c-373-\t}\nnet/handshake/request.c:374:\tif (test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED, \u0026req-\u003ehr_flags)) {\nnet/handshake/request.c-375-\t\t/* Request already completed */\n--\nnet/handshake/tlshd.c=61=static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,\n--\nnet/handshake/tlshd.c-70-\tnla_for_each_attr(nla, head, len, rem) {\nnet/handshake/tlshd.c:71:\t\tif (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)\nnet/handshake/tlshd.c-72-\t\t\ti++;\n--\nnet/handshake/tlshd.c-80-\tnla_for_each_attr(nla, head, len, rem) {\nnet/handshake/tlshd.c:81:\t\tif (nla_type(nla) == HANDSHAKE_A_DONE_REMOTE_AUTH)\nnet/handshake/tlshd.c-82-\t\t\ttreq-\u003eth_peerid[i++] = nla_get_u32(nla);\n--\nnet/handshake/tlshd.c=95=static void tls_handshake_done(struct handshake_req *req,\n--\nnet/handshake/tlshd.c-104-\tif (!status)\nnet/handshake/tlshd.c:105:\t\tset_bit(HANDSHAKE_F_REQ_SESSION, \u0026req-\u003ehr_flags);\nnet/handshake/tlshd.c-106-\n--\nnet/handshake/tlshd.c=151=static int tls_handshake_put_peer_identity(struct sk_buff *msg,\n--\nnet/handshake/tlshd.c-156-\tfor (i = 0; i \u003c treq-\u003eth_num_peerids; i++)\nnet/handshake/tlshd.c:157:\t\tif (nla_put_u32(msg, HANDSHAKE_A_ACCEPT_PEER_IDENTITY,\nnet/handshake/tlshd.c-158-\t\t\t\ttreq-\u003eth_peerid[i]) \u003c 0)\n--\nnet/handshake/tlshd.c=163=static int tls_handshake_put_certificate(struct sk_buff *msg,\n--\nnet/handshake/tlshd.c-171-\nnet/handshake/tlshd.c:172:\tentry_attr = nla_nest_start(msg, HANDSHAKE_A_ACCEPT_CERTIFICATE);\nnet/handshake/tlshd.c-173-\tif (!entry_attr)\n--\nnet/handshake/tlshd.c-175-\nnet/handshake/tlshd.c:176:\tif (nla_put_s32(msg, HANDSHAKE_A_X509_CERT,\nnet/handshake/tlshd.c-177-\t\t\ttreq-\u003eth_certificate) ||\nnet/handshake/tlshd.c:178:\t    nla_put_s32(msg, HANDSHAKE_A_X509_PRIVKEY,\nnet/handshake/tlshd.c-179-\t\t\ttreq-\u003eth_privkey)) {\n--\nnet/handshake/tlshd.c=196=static int tls_handshake_accept(struct handshake_req *req,\n--\nnet/handshake/tlshd.c-215-\nnet/handshake/tlshd.c:216:\tret = nla_put_s32(msg, HANDSHAKE_A_ACCEPT_SOCKFD, fd);\nnet/handshake/tlshd.c-217-\tif (ret \u003c 0)\nnet/handshake/tlshd.c-218-\t\tgoto out_cancel;\nnet/handshake/tlshd.c:219:\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, treq-\u003eth_type);\nnet/handshake/tlshd.c-220-\tif (ret \u003c 0)\n--\nnet/handshake/tlshd.c-222-\tif (treq-\u003eth_peername) {\nnet/handshake/tlshd.c:223:\t\tret = nla_put_string(msg, HANDSHAKE_A_ACCEPT_PEERNAME,\nnet/handshake/tlshd.c-224-\t\t\t\t     treq-\u003eth_peername);\n--\nnet/handshake/tlshd.c-228-\tif (treq-\u003eth_timeout_ms) {\nnet/handshake/tlshd.c:229:\t\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_TIMEOUT, treq-\u003eth_timeout_ms);\nnet/handshake/tlshd.c-230-\t\tif (ret \u003c 0)\n--\nnet/handshake/tlshd.c-233-\tif (treq-\u003eth_keyring) {\nnet/handshake/tlshd.c:234:\t\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_KEYRING,\nnet/handshake/tlshd.c-235-\t\t\t\t  treq-\u003eth_keyring);\n--\nnet/handshake/tlshd.c-239-\nnet/handshake/tlshd.c:240:\tret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_AUTH_MODE,\nnet/handshake/tlshd.c-241-\t\t\t  treq-\u003eth_auth_mode);\n--\nnet/handshake/tlshd.c-244-\tswitch (treq-\u003eth_auth_mode) {\nnet/handshake/tlshd.c:245:\tcase HANDSHAKE_AUTH_PSK:\nnet/handshake/tlshd.c-246-\t\tret = tls_handshake_put_peer_identity(msg, treq);\n--\nnet/handshake/tlshd.c-249-\t\tbreak;\nnet/handshake/tlshd.c:250:\tcase HANDSHAKE_AUTH_X509:\nnet/handshake/tlshd.c-251-\t\tret = tls_handshake_put_certificate(msg, treq);\n--\nnet/handshake/tlshd.c=267=static const struct handshake_proto tls_handshake_proto = {\nnet/handshake/tlshd.c:268:\t.hp_handler_class\t= HANDSHAKE_HANDLER_CLASS_TLSHD,\nnet/handshake/tlshd.c-269-\t.hp_privsize\t\t= sizeof(struct tls_handshake_req),\nnet/handshake/tlshd.c:270:\t.hp_flags\t\t= BIT(HANDSHAKE_F_PROTO_NOTIFY),\nnet/handshake/tlshd.c-271-\n--\nnet/handshake/tlshd.c=286=int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags)\n--\nnet/handshake/tlshd.c-294-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:295:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:296:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_UNAUTH;\nnet/handshake/tlshd.c-297-\n--\nnet/handshake/tlshd.c=312=int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags)\n--\nnet/handshake/tlshd.c-320-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:321:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:322:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_X509;\nnet/handshake/tlshd.c-323-\ttreq-\u003eth_certificate = args-\u003eta_my_cert;\n--\nnet/handshake/tlshd.c=341=int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags)\n--\nnet/handshake/tlshd.c-354-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:355:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_CLIENTHELLO;\nnet/handshake/tlshd.c:356:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_PSK;\nnet/handshake/tlshd.c-357-\ttreq-\u003eth_num_peerids = args-\u003eta_num_peerids;\n--\nnet/handshake/tlshd.c=375=int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags)\n--\nnet/handshake/tlshd.c-383-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:384:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;\nnet/handshake/tlshd.c:385:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_X509;\nnet/handshake/tlshd.c-386-\ttreq-\u003eth_certificate = args-\u003eta_my_cert;\n--\nnet/handshake/tlshd.c=403=int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags)\n--\nnet/handshake/tlshd.c-411-\ttreq = tls_handshake_req_init(req, args);\nnet/handshake/tlshd.c:412:\ttreq-\u003eth_type = HANDSHAKE_MSG_TYPE_SERVERHELLO;\nnet/handshake/tlshd.c:413:\ttreq-\u003eth_auth_mode = HANDSHAKE_AUTH_PSK;\nnet/handshake/tlshd.c-414-\ttreq-\u003eth_num_peerids = 1;\n--\nnet/handshake/tlshd.c=445=void tls_handshake_close(struct socket *sock)\n--\nnet/handshake/tlshd.c-451-\t\treturn;\nnet/handshake/tlshd.c:452:\tif (!test_and_clear_bit(HANDSHAKE_F_REQ_SESSION, \u0026req-\u003ehr_flags))\nnet/handshake/tlshd.c-453-\t\treturn;\n--\nnet/mac80211/mlme.c=5592=const char *ieee80211_get_reason_code_string(u16 reason_code)\n--\nnet/mac80211/mlme.c-5607-\tcase_WLAN(MIC_FAILURE);\nnet/mac80211/mlme.c:5608:\tcase_WLAN(4WAY_HANDSHAKE_TIMEOUT);\nnet/mac80211/mlme.c:5609:\tcase_WLAN(GROUP_KEY_HANDSHAKE_TIMEOUT);\nnet/mac80211/mlme.c-5610-\tcase_WLAN(IE_DIFFERENT);\n--\nnet/sunrpc/svc_xprt.c=224=void svc_xprt_received(struct svc_xprt *xprt)\n--\nnet/sunrpc/svc_xprt.c-245-\tif (READ_ONCE(xprt-\u003expt_flags) \u0026\nnet/sunrpc/svc_xprt.c:246:\t    (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE) |\nnet/sunrpc/svc_xprt.c-247-\t     BIT(XPT_DATA) | BIT(XPT_DEFERRED)))\n--\nnet/sunrpc/svc_xprt.c=472=static bool svc_xprt_ready(struct svc_xprt *xprt)\n--\nnet/sunrpc/svc_xprt.c-489-\t\treturn false;\nnet/sunrpc/svc_xprt.c:490:\tif (xpt_flags \u0026 (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))\nnet/sunrpc/svc_xprt.c-491-\t\treturn true;\n--\nnet/sunrpc/svc_xprt.c=832=static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)\n--\nnet/sunrpc/svc_xprt.c-860-\t\tsvc_xprt_received(xprt);\nnet/sunrpc/svc_xprt.c:861:\t} else if (test_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags)) {\nnet/sunrpc/svc_xprt.c-862-\t\txprt-\u003expt_ops-\u003expo_handshake(xprt);\n--\nnet/sunrpc/svcauth_unix.c=1101=svcauth_tls_accept(struct svc_rqst *rqstp)\n--\nnet/sunrpc/svcauth_unix.c-1147-\nnet/sunrpc/svcauth_unix.c:1148:\t\tset_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcauth_unix.c-1149-\t\tsvc_xprt_enqueue(xprt);\n--\nnet/sunrpc/svcsock.c=85=enum {\nnet/sunrpc/svcsock.c:86:\tSVC_HANDSHAKE_TO\t= 5U * HZ\nnet/sunrpc/svcsock.c-87-};\n--\nnet/sunrpc/svcsock.c=401=static void svc_data_ready(struct sock *sk)\n--\nnet/sunrpc/svcsock.c-411-\t\ttrace_svcsock_data_ready(\u0026svsk-\u003esk_xprt, 0);\nnet/sunrpc/svcsock.c:412:\t\tif (test_bit(XPT_HANDSHAKE, \u0026svsk-\u003esk_xprt.xpt_flags))\nnet/sunrpc/svcsock.c-413-\t\t\treturn;\n--\nnet/sunrpc/svcsock.c=462=static void svc_tcp_handshake_done(void *data, int status, key_serial_t peerid)\n--\nnet/sunrpc/svcsock.c-471-\t}\nnet/sunrpc/svcsock.c:472:\tclear_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcsock.c-473-\tcomplete_all(\u0026svsk-\u003esk_handshake_done);\n--\nnet/sunrpc/svcsock.c=482=static void svc_tcp_handshake(struct svc_xprt *xprt)\n--\nnet/sunrpc/svcsock.c-508-\tret = wait_for_completion_interruptible_timeout(\u0026svsk-\u003esk_handshake_done,\nnet/sunrpc/svcsock.c:509:\t\t\t\t\t\t\tSVC_HANDSHAKE_TO);\nnet/sunrpc/svcsock.c-510-\tif (ret \u003c= 0) {\n--\nnet/sunrpc/svcsock.c-537-out_failed:\nnet/sunrpc/svcsock.c:538:\tclear_bit(XPT_HANDSHAKE, \u0026xprt-\u003expt_flags);\nnet/sunrpc/svcsock.c-539-\tset_bit(XPT_DATA, \u0026xprt-\u003expt_flags);\n--\nnet/sunrpc/xprtsock.c=110=static struct ctl_table xs_tunables_table[] = {\n--\nnet/sunrpc/xprtsock.c-196- */\nnet/sunrpc/xprtsock.c:197:#define XS_TLS_HANDSHAKE_TO\t(10U * HZ)\nnet/sunrpc/xprtsock.c-198-\n--\nnet/sunrpc/xprtsock.c=2616=static int xs_tls_handshake_sync(struct rpc_xprt *lower_xprt, struct xprtsec_parms *xprtsec)\n--\nnet/sunrpc/xprtsock.c-2650-\trc = wait_for_completion_interruptible_timeout(\u0026lower_transport-\u003ehandshake_done,\nnet/sunrpc/xprtsock.c:2651:\t\t\t\t\t\t       XS_TLS_HANDSHAKE_TO);\nnet/sunrpc/xprtsock.c-2652-\tif (rc \u003c= 0) {\n--\nnet/tls/tls_sw.c=1531=static int tls_check_pending_rekey(struct sock *sk, struct tls_context *ctx,\n--\nnet/tls/tls_sw.c-1538-\nnet/tls/tls_sw.c:1539:\tif (likely(tlm-\u003econtrol != TLS_RECORD_TYPE_HANDSHAKE))\nnet/tls/tls_sw.c-1540-\t\treturn 0;\n--\nnet/tls/tls_sw.c-1550-\nnet/tls/tls_sw.c:1551:\tif (hs_type == TLS_HANDSHAKE_KEYUPDATE) {\nnet/tls/tls_sw.c-1552-\t\tstruct tls_sw_context_rx *rx_ctx = ctx-\u003epriv_ctx_rx;\n--\nnet/wireless/core.c=853=int wiphy_register(struct wiphy *wiphy)\n--\nnet/wireless/core.c-968-\tif (WARN_ON(wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/core.c:969:\t\t\t\t\t    NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X) \u0026\u0026\nnet/wireless/core.c-970-\t\t    (!rdev-\u003eops-\u003eset_pmk || !rdev-\u003eops-\u003edel_pmk)))\n--\nnet/wireless/nl80211.c=1128=nl80211_wowlan_policy[NUM_NL80211_WOWLAN_TRIG] = {\n--\nnet/wireless/nl80211.c-1134-\t[NL80211_WOWLAN_TRIG_EAP_IDENT_REQUEST] = { .type = NLA_FLAG },\nnet/wireless/nl80211.c:1135:\t[NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE] = { .type = NLA_FLAG },\nnet/wireless/nl80211.c-1136-\t[NL80211_WOWLAN_TRIG_RFKILL_RELEASE] = { .type = NLA_FLAG },\n--\nnet/wireless/nl80211.c=2068=static int nl80211_send_wowlan(struct sk_buff *msg,\n--\nnet/wireless/nl80211.c-2093-\t     nla_put_flag(msg, NL80211_WOWLAN_TRIG_EAP_IDENT_REQUEST)) ||\nnet/wireless/nl80211.c:2094:\t    ((rdev-\u003ewiphy.wowlan-\u003eflags \u0026 WIPHY_WOWLAN_4WAY_HANDSHAKE) \u0026\u0026\nnet/wireless/nl80211.c:2095:\t     nla_put_flag(msg, NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE)) ||\nnet/wireless/nl80211.c-2096-\t    ((rdev-\u003ewiphy.wowlan-\u003eflags \u0026 WIPHY_WOWLAN_RFKILL_RELEASE) \u0026\u0026\n--\nnet/wireless/nl80211.c=12936=static int nl80211_crypto_settings(struct cfg80211_registered_device *rdev,\n--\nnet/wireless/nl80211.c-13026-\t\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:13027:\t\t\t\t\t     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK) \u0026\u0026\nnet/wireless/nl80211.c-13028-\t\t    !wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:13029:\t\t\t\t\t     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_AP_PSK))\nnet/wireless/nl80211.c-13030-\t\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=13995=static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)\n--\nnet/wireless/nl80211.c-14023-\t    !wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:14024:\t\t\t\t     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X))\nnet/wireless/nl80211.c-14025-\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=15563=static int nl80211_get_wowlan(struct sk_buff *skb, struct genl_info *info)\n--\nnet/wireless/nl80211.c-15608-\t\t    (rdev-\u003ewiphy.wowlan_config-\u003efour_way_handshake \u0026\u0026\nnet/wireless/nl80211.c:15609:\t\t     nla_put_flag(msg, NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE)) ||\nnet/wireless/nl80211.c-15610-\t\t    (rdev-\u003ewiphy.wowlan_config-\u003erfkill_release \u0026\u0026\n--\nnet/wireless/nl80211.c=15813=static int nl80211_set_wowlan(struct sk_buff *skb, struct genl_info *info)\n--\nnet/wireless/nl80211.c-15875-\nnet/wireless/nl80211.c:15876:\tif (tb[NL80211_WOWLAN_TRIG_4WAY_HANDSHAKE]) {\nnet/wireless/nl80211.c:15877:\t\tif (!(wowlan-\u003eflags \u0026 WIPHY_WOWLAN_4WAY_HANDSHAKE))\nnet/wireless/nl80211.c-15878-\t\t\treturn -EINVAL;\n--\nnet/wireless/nl80211.c=18434=static int nl80211_set_pmk(struct sk_buff *skb, struct genl_info *info)\n--\nnet/wireless/nl80211.c-18445-\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\nnet/wireless/nl80211.c:18446:\t\t\t\t     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X))\nnet/wireless/nl80211.c-18447-\t\treturn -EOPNOTSUPP;\n--\nnet/wireless/nl80211.c=18472=static int nl80211_del_pmk(struct sk_buff *skb, struct genl_info *info)\n--\nnet/wireless/nl80211.c-18483-\tif (!wiphy_ext_feature_isset(\u0026rdev-\u003ewiphy,\n\n"
}

55/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 55597
							output: 20
							thoughts: 1628

Thoughts:

**Identifying Relevant Symbols for Targeted Fuzzing**

Okay, let's break this down systematically. My goal here is to identify the most relevant functions in the kernel modifications for fuzzing, specifically focusing on the new handshake code. First, let's start by looking at `net/handshake/Kconfig` to confirm that `CONFIG_NET_HANDSHAKE` is enabled.

Next, I'll need a list of the required configurations to compile the code. The following configurations are needed: `VFS`, `EVENTFD`, `EPOLL`, `USERFAULTFD`, `BPF_SYSCALL`, `NTSYNC`, `KCM`, `GPIO_CDEV`, `IO_URING`, `MEDIA_SUPPORT`, `NET_HANDSHAKE`, and `XFS_FS`.

Now, the crucial step: identifying the *right* symbols to target.  I need to avoid the fuzzing trap of picking overly generic, "ubiquitous" functions like `sys_openat` or `do_sys_openat2`, which will dilute the fuzzing effort. Instead, I want to find the feature-specific entrypoints or functions that specifically implement the new logic.

Following the guidance, I need to look for functions that implement the *logic being added or altered*. My focus is on functions in .c files. Let's start by methodically reviewing each function:

1.  `receive_fd` (`fs/file.c`): This isn't ubiquitous; it's specific to file descriptor passing via `scm_detach_fds`, `pidfd_getfd`, `seccomp_handle_addfd`, `io_install_fixed_fd`, and `vduse`. This looks promising.
2.  `scm_recv_one_fd` (`net/core/scm.c`):  Again, not ubiquitous. This is dedicated to passing file descriptors across UNIX domain sockets (SCM_RIGHTS). Good candidate.
3.  `do_eventfd` or `__do_sys_eventfd2` (`fs/eventfd.c`): I need to be careful with inlined functions. Based on how `SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)` is defined, I see that `__do_sys_eventfd2` is the syscall symbol.
4.  `__do_sys_open_tree_attr` (`fs/namespace.c`) and `__do_sys_fsmount` (`fs/namespace.c`): These look like strong candidates as system calls.
5.  `bpf_iter_new_fd` (`kernel/bpf/bpf_iter.c`): Worth checking.
6.  `bpf_token_create` (`kernel/bpf/token.c`): Worth checking.
7.  `new_userfaultfd` or `__do_sys_userfaultfd` (`mm/userfaultfd.c`): The syscall symbol looks like `__do_sys_userfaultfd`.
8.  `xfs_open_by_handle` (`fs/xfs/xfs_handle.c`): Potentially relevant.
9.  `kcm_ioctl` (`net/kcm/kcmsock.c`): Could be valuable.
10. `ntsync_obj_get_fd` (`drivers/misc/ntsync.c`): Let's keep it on the list.
11. `media_request_alloc` (`drivers/media/mc/mc-request.c`): Relevant.
12. `handshake_nl_accept_doit` (`net/handshake/netlink.c`): This is very relevant given the area we are focusing on.
13. `io_create_mock_file` (`io_uring/mock_file.c`): Interesting, depending on its use within the modified code.
14. `linehandle_create` (`drivers/gpio/gpiolib-cdev.c`): Possibly relevant.

I need to confirm whether these functions have reliable symbol names in the kernel's vmlinux, specifically syscalls.  Modern x86_64 Linux system calls defined with `SYSCALL_DEFINE...` typically use names like `__x64_sys_fsmount`, and `__do_sys_fsmount`. The key is to distinguish syscalls from internal functions, so the fuzzing tools can find them. Other functions: `receive_fd`, `scm_recv_one_fd`, `bpf_iter_new_fd`, `bpf_token_create`, `xfs_open_by_handle`, `media_request_

56/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "bpf_token_create"
}

Results:

{
  "Output": "include/linux/bpf.h=2909=void bpf_token_put(struct bpf_token *token);\ninclude/linux/bpf.h:2910:int bpf_token_create(union bpf_attr *attr);\ninclude/linux/bpf.h-2911-struct bpf_token *bpf_token_get_from_fd(u32 ufd);\n--\ninclude/linux/lsm_hook_defs.h=449=LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free, struct bpf_prog *prog)\ninclude/linux/lsm_hook_defs.h:450:LSM_HOOK(int, 0, bpf_token_create, struct bpf_token *token, union bpf_attr *attr,\ninclude/linux/lsm_hook_defs.h-451-\t const struct path *path)\n--\ninclude/linux/security.h=2309=extern void security_bpf_prog_free(struct bpf_prog *prog);\ninclude/linux/security.h:2310:extern int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,\ninclude/linux/security.h-2311-\t\t\t\t     const struct path *path);\n--\ninclude/linux/security.h=2347=static inline void security_bpf_prog_free(struct bpf_prog *prog)\n--\ninclude/linux/security.h-2349-\ninclude/linux/security.h:2350:static inline int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,\ninclude/linux/security.h-2351-\t\t\t\t\t    const struct path *path)\n--\nkernel/bpf/bpf_lsm.c=297=BTF_ID(func, bpf_lsm_bpf_prog_load)\nkernel/bpf/bpf_lsm.c:298:BTF_ID(func, bpf_lsm_bpf_token_create)\nkernel/bpf/bpf_lsm.c-299-BTF_ID(func, bpf_lsm_bpf_token_free)\n--\nkernel/bpf/syscall.c=6226=static int token_create(union bpf_attr *attr)\n--\nkernel/bpf/syscall.c-6234-\nkernel/bpf/syscall.c:6235:\treturn bpf_token_create(attr);\nkernel/bpf/syscall.c-6236-}\n--\nkernel/bpf/token.c=107=const struct file_operations bpf_token_fops = {\n--\nkernel/bpf/token.c-111-\nkernel/bpf/token.c:112:int bpf_token_create(union bpf_attr *attr)\nkernel/bpf/token.c-113-{\n--\nkernel/bpf/token.c-187-\nkernel/bpf/token.c:188:\terr = security_bpf_token_create(token, attr, \u0026path);\nkernel/bpf/token.c-189-\tif (err)\n--\nsecurity/security.c=5370=int security_bpf_prog_load(struct bpf_prog *prog, union bpf_attr *attr,\n--\nsecurity/security.c-5385-/**\nsecurity/security.c:5386: * security_bpf_token_create() - Check if creating of BPF token is allowed\nsecurity/security.c-5387- * @token: BPF token object\n--\nsecurity/security.c-5395- */\nsecurity/security.c:5396:int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,\nsecurity/security.c-5397-\t\t\t      const struct path *path)\n--\nsecurity/security.c-5404-\nsecurity/security.c:5405:\trc = call_int_hook(bpf_token_create, token, attr, path);\nsecurity/security.c-5406-\tif (unlikely(rc))\n--\nsecurity/selinux/hooks.c=7306=static int selinux_bpf_prog_load(struct bpf_prog *prog, union bpf_attr *attr,\n--\nsecurity/selinux/hooks.c-7326-\nsecurity/selinux/hooks.c:7327:static int selinux_bpf_token_create(struct bpf_token *token,\nsecurity/selinux/hooks.c-7328-\t\t\t\t    union bpf_attr *attr,\n--\nsecurity/selinux/hooks.c=7560=static struct security_hook_list selinux_hooks[] __ro_after_init = {\n--\nsecurity/selinux/hooks.c-7842-\tLSM_HOOK_INIT(bpf_prog_load, selinux_bpf_prog_load),\nsecurity/selinux/hooks.c:7843:\tLSM_HOOK_INIT(bpf_token_create, selinux_bpf_token_create),\nsecurity/selinux/hooks.c-7844-\tLSM_HOOK_INIT(bpf_token_cmd, selinux_bpf_token_cmd),\n--\ntools/lib/bpf/bpf.c=1411=int bpf_prog_bind_map(int prog_fd, int map_fd,\n--\ntools/lib/bpf/bpf.c-1429-\ntools/lib/bpf/bpf.c:1430:int bpf_token_create(int bpffs_fd, struct bpf_token_create_opts *opts)\ntools/lib/bpf/bpf.c-1431-{\n--\ntools/lib/bpf/bpf.c-1435-\ntools/lib/bpf/bpf.c:1436:\tif (!OPTS_VALID(opts, bpf_token_create_opts))\ntools/lib/bpf/bpf.c-1437-\t\treturn libbpf_err(-EINVAL);\n--\ntools/lib/bpf/bpf.h=717=LIBBPF_API int bpf_prog_test_run_opts(int prog_fd,\n--\ntools/lib/bpf/bpf.h-719-\ntools/lib/bpf/bpf.h:720:struct bpf_token_create_opts {\ntools/lib/bpf/bpf.h-721-\tsize_t sz; /* size of this struct for forward/backward compatibility */\n--\ntools/lib/bpf/bpf.h-724-};\ntools/lib/bpf/bpf.h:725:#define bpf_token_create_opts__last_field flags\ntools/lib/bpf/bpf.h-726-\ntools/lib/bpf/bpf.h-727-/**\ntools/lib/bpf/bpf.h:728: * @brief **bpf_token_create()** creates a new instance of BPF token derived\ntools/lib/bpf/bpf.h-729- * from specified BPF FS mount point.\n--\ntools/lib/bpf/bpf.h-740- */\ntools/lib/bpf/bpf.h:741:LIBBPF_API int bpf_token_create(int bpffs_fd,\ntools/lib/bpf/bpf.h:742:\t\t\t\tstruct bpf_token_create_opts *opts);\ntools/lib/bpf/bpf.h-743-\n--\ntools/lib/bpf/libbpf.c=5147=static int bpf_object_prepare_token(struct bpf_object *obj)\n--\ntools/lib/bpf/libbpf.c-5172-\ntools/lib/bpf/libbpf.c:5173:\ttoken_fd = bpf_token_create(bpffs_fd, 0);\ntools/lib/bpf/libbpf.c-5174-\tclose(bpffs_fd);\n--\ntools/lib/bpf/libbpf.map=411=LIBBPF_1.4.0 {\n--\ntools/lib/bpf/libbpf.map-414-\t\tbpf_raw_tracepoint_open_opts;\ntools/lib/bpf/libbpf.map:415:\t\tbpf_token_create;\ntools/lib/bpf/libbpf.map-416-\t\tbtf__new_split;\n--\ntools/testing/selftests/bpf/prog_tests/token.c=287=static void child(int sock_fd, struct bpffs_opts *opts, child_callback_fn callback)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-389-\t/* create BPF token FD and pass it to parent for some extra checks */\ntools/testing/selftests/bpf/prog_tests/token.c:390:\ttoken_fd = bpf_token_create(bpffs_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-391-\tif (!ASSERT_GT(token_fd, 0, \"child_token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=506=static int userns_map_create(int mnt_fd, struct token_lsm *lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-512-\t/* create BPF token from BPF FS mount */\ntools/testing/selftests/bpf/prog_tests/token.c:513:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-514-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=574=static int userns_btf_load(int mnt_fd, struct token_lsm *lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-583-\t/* create BPF token from BPF FS mount */\ntools/testing/selftests/bpf/prog_tests/token.c:584:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-585-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=643=static int userns_prog_load(int mnt_fd, struct token_lsm *lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-659-\t/* create BPF token from BPF FS mount */\ntools/testing/selftests/bpf/prog_tests/token.c:660:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-661-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n--\ntools/testing/selftests/bpf/prog_tests/token.c=1108=static int userns_bpf_token_info(int mnt_fd, struct token_lsm *lsm_skel)\n--\ntools/testing/selftests/bpf/prog_tests/token.c-1114-\t/* create BPF token from BPF FS mount */\ntools/testing/selftests/bpf/prog_tests/token.c:1115:\ttoken_fd = bpf_token_create(mnt_fd, NULL);\ntools/testing/selftests/bpf/prog_tests/token.c-1116-\tif (!ASSERT_GT(token_fd, 0, \"token_create\")) {\n"
}

57/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 61354
							output: 26
							thoughts: 591

Thoughts:

**My Analysis of FD_PREPARE Updates**

Okay, so I've been digging into where `FD_PREPARE` was updated, and I've got a pretty good list. It looks like the changes are in key functions across various parts of the kernel: `bpf_token_create` in `kernel/bpf/token.c`, `bpf_iter_new_fd` in `kernel/bpf/bpf_iter.c`, `receive_fd` in `fs/file.c`, `scm_recv_one_fd` in `net/core/scm.c`, `new_userfaultfd` in `mm/userfaultfd.c`, `do_epoll_create` in `fs/eventpoll.c`, `do_eventfd` in `fs/eventfd.c`, `ntsync_obj_get_fd` in `drivers/misc/ntsync.c`, `media_request_alloc` in `drivers/media/mc/mc-request.c` and `xfs_open_by_handle` in `fs/xfs/xfs_handle.c`.

Now, the next logical step is to understand the configuration implications of these updates. I need to figure out which kernel configuration options enable these code paths. So, based on my analysis of the dependencies, it looks like:

*   `receive_fd` and `scm_recv_one_fd` are pretty fundamental – they rely on core networking and file system code, which implies `NET` for the network component.
*   `bpf_token_create` and `bpf_iter_new_fd` depend on `BPF_SYSCALL`.
*   `new_userfaultfd` depends on `USERFAULTFD`.
*   `ntsync_obj_get_fd` relies on `NTSYNC`.
*   `media_request_alloc` depends on `MEDIA_SUPPORT` and `MEDIA_CONTROLLER`.
*   `xfs_open_by_handle` depends on `XFS_FS`.

Given the importance of `USERFAULTFD`, I need to double-check its direct dependencies. I will have a more informed next step with that information.

58/2

2026/09/19 01:39

tool

grepper

Error:

no matches

Args:

{
  "Expression": "config USERFAULTFD",
  "PathPrefix": "fs/"
}

Results:

{
  "error": "no matches"
}

59/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 62469
							output: 18
							thoughts: 10

Thoughts:

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

**Hunting Down USERFAULTFD Configuration**

Okay, so I need to dig into the `USERFAULTFD` configuration. My initial thought process is to bypass the usual suspects, and just start looking for it directly. I'm not going to beat around the bush; I'm going to jump straight to the relevant configuration settings. I'm thinking of kernel parameters, sysfs entries, maybe even some obscure module options if it's got one. I'm assuming, given what I'm working on, that the configuration would have been carefully considered given the nature of the feature so it would be likely available to change at runtime. I'll need to figure out what's currently enabled or disabled. My guess is it's not something that's simply on by default, so I'll probably be chasing down some disabled state, or specific access permissions. I'll focus on the obvious first, but be ready to drop into the code if it's not as simple as a sysctl entry. I'll be looking for relevant kernel builds and patches too, that could also give me an idea about the configuration.

60/2

2026/09/19 01:39

tool

grepper

Args:

{
  "Expression": "config USERFAULTFD"
}

Results:

{
  "Output": "mm/Kconfig=1372=config HAVE_ARCH_USERFAULTFD_MINOR\n--\nmm/Kconfig-1376-\nmm/Kconfig:1377:config USERFAULTFD_RWP\nmm/Kconfig-1378-\tdef_bool y\n--\nmm/Kconfig-1385-\nmm/Kconfig:1386:menuconfig USERFAULTFD\nmm/Kconfig-1387-\tbool \"Enable userfaultfd() system call\"\n"
}

61/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 62880
							output: 33
							thoughts: 17

Thoughts:

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

**Navigating the Labyrinth of Kernel Configuration**

Okay, time to dive into this. Based on the task at hand, I'm thinking I need to zero in on `mm/Kconfig`. That's where a lot of the memory management options and dependencies are defined in the kernel's configuration system, so it's a good starting point for whatever I'm troubleshooting or investigating. And since there's a specific line number mentioned, I'm going to start around line 1386. That likely points to a specific configuration option, definition, or perhaps a conditional block related to the memory management subsystem. Going directly to that location will save some time rather than sifting through the file from the start. Let's see what's there...

62/2

2026/09/19 01:39

tool

read-file

Args:

{
  "File": "mm/Kconfig",
  "FirstLine": 1385,
  "LineCount": 10
}

Results:

{
  "Contents": "1385:\t\n1386:\tmenuconfig USERFAULTFD\n1387:\t\tbool \"Enable userfaultfd() system call\"\n1388:\t\tdepends on MMU\n1389:\t\thelp\n1390:\t\t  Enable the userfaultfd() system call that allows to intercept and\n1391:\t\t  handle page faults in userland.\n1392:\t\n1393:\tconfig PTE_MARKER_UFFD_WP\n1394:\t\tbool \"Userfaultfd write protection support for shmem/hugetlbfs\"\n"
}

63/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 63256
							output: 29
							thoughts: 19

Thoughts:

Here's my summary, as though I'm thinking it:

**Digging into Kernel Configuration for BPF Syscall**

Alright, time to get my hands dirty. I need to refresh my memory on the kernel config options related to BPF syscalls, particularly `BPF_SYSCALL`. Let's jump into the `init/Kconfig` file and take a look. I'm assuming that's where I can find the primary switch for enabling or disabling that functionality, as it's the usual spot for such core features. I need to verify that it's enabled and consider any dependencies or associated options that might be relevant to the specific BPF use-case I'm working on right now. A quick check of the Kconfig should clarify things.

64/2

2026/09/19 01:39

tool

grepper

Error:

no matches

Args:

{
  "Expression": "config BPF_SYSCALL",
  "PathPrefix": "init/"
}

Results:

{
  "error": "no matches"
}

65/2

2026/09/19 01:39

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 63481
							output: 21
							thoughts: 13

Thoughts:

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

**Hunting Down BPF_SYSCALL in the Configuration**

Alright, let's get down to brass tacks. I need to locate the `config BPF_SYSCALL` option. This isn't just a casual search; I need to quickly and efficiently pinpoint its definition within the kernel configuration system. This usually means diving into the Kconfig files, likely spread across various subdirectories reflecting different kernel subsystems. I'm thinking I'll start with a broad search – maybe using `grep` or a similar tool to look across the entire kernel source tree, or the generated `.config` file itself if I have it at hand. That'll give me a quick list of places where `BPF_SYSCALL` is even *mentioned*. From there, I'll need to assess the context. Where it's defined, the dependencies it has, and perhaps where it's *used* by other configurations, or code. Context is key here; a simple grep hit isn't enough. I'm looking for the definitive source and any relevant dependencies. So, time to get searching and then start understanding.

66/2

2026/09/19 01:40

tool

grepper

Args:

{
  "Expression": "config BPF_SYSCALL"
}

Results:

{
  "Output": "kernel/bpf/Kconfig=25=menu \"BPF subsystem\"\nkernel/bpf/Kconfig-26-\nkernel/bpf/Kconfig:27:config BPF_SYSCALL\nkernel/bpf/Kconfig-28-\tbool \"Enable bpf() system call\"\n"
}

67/2

2026/09/19 01:40

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 63851
							output: 34
							thoughts: 19

Thoughts:

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

**Examining BPF Kconfig Configuration**

Okay, I need to dive into the kernel's BPF configuration. My initial instinct is to go straight to `kernel/bpf/Kconfig`, specifically around line 27. I'm probably looking for the core BPF feature enablement flag, or maybe I'm trying to recall a related option that I want to double-check. Could be an experimental feature flag, or something tied to a specific BPF helper version. I suspect line 27 will likely lead me to the main entry point or a crucial dependency in that Kconfig file. I am hoping to get to the root cause of an issue I'm working through. I'm expecting this to provide the base configuration that all further configuration is reliant on. Time to see what's there and refresh my memory on the build options.

68/2

2026/09/19 01:40

tool

read-file

Args:

{
  "File": "kernel/bpf/Kconfig",
  "FirstLine": 25,
  "LineCount": 15
}

Results:

{
  "Contents": "  25:\tmenu \"BPF subsystem\"\n  26:\t\n  27:\tconfig BPF_SYSCALL\n  28:\t\tbool \"Enable bpf() system call\"\n  29:\t\tselect BPF\n  30:\t\tselect IRQ_WORK\n  31:\t\tselect NEED_TASKS_RCU\n  32:\t\tselect TASKS_TRACE_RCU\n  33:\t\tselect BINARY_PRINTF\n  34:\t\tselect NET_SOCK_MSG if NET\n  35:\t\tselect NET_XGRESS if NET\n  36:\t\tselect PAGE_POOL if NET\n  37:\t\tdefault n\n  38:\t\thelp\n  39:\t\t  Enable the bpf() system call that allows to manipulate BPF programs\n"
}

69/2

2026/09/19 01:40

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 64294
							output: 19
							thoughts: 11

Thoughts:

Here's your summary, as if it were my thought process:

**Diving into Configuration: NTSYNC**

Alright, time to get granular. I need to take a look at the `config NTSYNC` settings. I know this is where the core network time synchronization parameters are. I'm going to want to examine how this system is configured to interact with the NTP servers, and what specific settings are enabled. I'll need to confirm the configured server addresses, the authentication details if any, and the configured stratum level, to assess the accuracy of time synchronization with external servers. I need to make sure this NTSYNC setting is optimally configured to prevent any time drift or synchronization issues within the system. Let's see what we're working with here.

70/2

2026/09/19 01:40

tool

grepper

Args:

{
  "Expression": "config NTSYNC"
}

Results:

{
  "Output": "drivers/misc/Kconfig=441=config OPEN_DICE\n--\ndrivers/misc/Kconfig-453-\ndrivers/misc/Kconfig:454:config NTSYNC\ndrivers/misc/Kconfig-455-\ttristate \"NT synchronization primitive emulation\"\n"
}

71/2

2026/09/19 01:40

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 64570
							output: 34
							thoughts: 18

Thoughts:

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

**Diving into the Kernel Config**

Okay, time to dig in. Something's nagging at me, and I have a feeling the answer lies in the kernel's configuration options. Let's start with `drivers/misc/Kconfig`. Line 454... yeah, that's where I need to be. Hopefully, whatever is bugging me is addressed within that particular section. Time to start reading...

72/2

2026/09/19 01:40

tool

read-file

Args:

{
  "File": "drivers/misc/Kconfig",
  "FirstLine": 453,
  "LineCount": 10
}

Results:

{
  "Contents": " 453:\t\n 454:\tconfig NTSYNC\n 455:\t\ttristate \"NT synchronization primitive emulation\"\n 456:\t\thelp\n 457:\t\t  This module provides kernel support for emulation of Windows NT\n 458:\t\t  synchronization primitives. It is not a hardware driver.\n 459:\t\n 460:\t\t  To compile this driver as a module, choose M here: the\n 461:\t\t  module will be called ntsync.\n 462:\t\n"
}

73/2

2026/09/19 01:40

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 64873
							output: 17
							thoughts: 9

Thoughts:

Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue:

**Checking the Configuration Kernel Configuration Management (KCM)**

Alright, time to get to the heart of the matter. I need to take a look at the `config KCM`. It's my go-to starting point when troubleshooting, especially after the recent system update. It’s where I'll find the core configurations related to how we're managing the kernel and its various parameters. I’m thinking, does the kernel configuration match the specs? Are there any obvious flags that are set wrong, particularly related to the areas affected by the recent changes? I'll probably start with the memory allocation, interrupt handling, and any power management settings. After all, a misconfigured KCM can lead to all sorts of performance bottlenecks or outright instability. It's the first place I always check to get a good overview of the state. It will allow me to narrow down the problem.

74/2

2026/09/19 01:40

tool

grepper

Args:

{
  "Expression": "config KCM"
}

Results:

{
  "Output": "init/Kconfig=2003=config MEMBARRIER\n--\ninit/Kconfig-2014-\ninit/Kconfig:2015:config KCMP\ninit/Kconfig-2016-\tbool \"Enable kcmp() system call\" if EXPERT\n"
}

75/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 65190
							output: 33
							thoughts: 13

Thoughts:

Here's a summary of my immediate thought process, crafted from the prompt:

**Kconfig Inspection: Where Do We Start?**

Alright, the instruction is clear: start by examining `net/kcm/Kconfig`. This immediately tells me we're likely dealing with configuration options related to a specific kernel component, namely KCM (Kernel Connection Manager, I presume?). This means it's time to delve into the heart of the configuration. I want to see how this particular KCM module is controlled. What features are exposed to the user for configuration? Are there any dependencies on other kernel components? How granular is the control, and what are the defaults? My initial goal is to understand the scope and the landscape of settings that `Kconfig` defines for this subsystem. Let's see what's in there.

76/2

2026/09/19 01:41

tool

read-file

Args:

{
  "File": "net/kcm/Kconfig",
  "FirstLine": 1,
  "LineCount": 20
}

Results:

{
  "Contents": "   1:\t# SPDX-License-Identifier: GPL-2.0-only\n   2:\t\n   3:\tconfig AF_KCM\n   4:\t\ttristate \"KCM sockets\"\n   5:\t\tdepends on INET\n   6:\t\tselect BPF_SYSCALL\n   7:\t\tselect STREAM_PARSER\n   8:\t\thelp\n   9:\t\t  KCM (Kernel Connection Multiplexor) sockets provide a method\n  10:\t\t  for multiplexing messages of a message-based application\n  11:\t\t  protocol over kernel connections (e.g. TCP connections).\n"
}

77/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 65559
							output: 29
							thoughts: 37

Thoughts:

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

**Kernel Media Subsystem Audit - Quick Scan**

Alright, that familiar string popped up: `AF_KCM`! Always catches my eye. Time for a quick sanity check within the media subsystem. My immediate thought is to verify the configuration options directly related to this area. Let's see... I'm diving into `drivers/media/Kconfig` right away. I need to confirm the status of `MEDIA_SUPPORT` and `MEDIA_CONTROLLER` in relation to this, and how `AF_KCM` influences their enablement or dependencies. I'm looking for any potential configuration conflicts or missing dependencies right off the bat, as well as a more general idea of how this part of the subsystem is handled. I need to assess its influence on a high level and make sure the design makes sense.

78/2

2026/09/19 01:41

tool

grepper

Args:

{
  "Expression": "config MEDIA_CONTROLLER",
  "PathPrefix": "drivers/media/"
}

Results:

{
  "Output": "drivers/media/Kconfig=160=config VIDEO_DEV\n--\ndrivers/media/Kconfig-169-\ndrivers/media/Kconfig:170:config MEDIA_CONTROLLER\ndrivers/media/Kconfig-171-\tbool \"Media Controller API\"\n--\ndrivers/media/mc/Kconfig-6-\ndrivers/media/mc/Kconfig:7:config MEDIA_CONTROLLER_DVB\ndrivers/media/mc/Kconfig-8-\tbool \"Enable Media controller for DVB (EXPERIMENTAL)\"\n"
}

79/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 65948
							output: 34
							thoughts: 18

Thoughts:

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

**Diving into the Media Subsystem Configuration**

Okay, let's zero in on `drivers/media/Kconfig`. I need to get a handle on what's configurable within the media subsystem. I'm thinking around line 170. I suspect there's a specific option related to [your assumed area of expertise - e.g., a specific camera module, a particular video codec, or perhaps a relevant DMA engine setting]. I'm going to scan that section to see how that feature is defined, if it's tristated, what dependencies it might have on other kernel modules, and the default settings. My goal is to quickly assess its build configuration. This will give me a better understanding of what’s enabled and disabled and how that impacts my current work on [insert likely area of work, e.g. system power, device configuration, new feature integration].

80/2

2026/09/19 01:41

tool

read-file

Args:

{
  "File": "drivers/media/Kconfig",
  "FirstLine": 165,
  "LineCount": 20
}

Results:

{
  "Contents": " 165:\t\tselect VIDEOBUF2_V4L2 if VIDEOBUF2_CORE\n 166:\t\thelp\n 167:\t\t  Enables the V4L2 API, used by cameras, analog TV, video grabbers,\n 168:\t\t  radio devices and by some input devices.\n 169:\t\n 170:\tconfig MEDIA_CONTROLLER\n 171:\t\tbool \"Media Controller API\"\n 172:\t\tdefault MEDIA_CAMERA_SUPPORT || MEDIA_ANALOG_TV_SUPPORT || MEDIA_DIGITAL_TV_SUPPORT || MEDIA_PLATFORM_SUPPORT\n 173:\t\thelp\n 174:\t\t  Enable the media controller API used to query media devices internal\n 175:\t\t  topology and configure it dynamically.\n 176:\t\n 177:\t\t  This API is mostly used by camera interfaces in embedded platforms.\n 178:\t\n 179:\t#\n 180:\t# DVB Core\n 181:\t#\tOnly enables if one of DTV is selected\n 182:\t#\n 183:\t\n 184:\tconfig DVB_CORE\n"
}

81/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 66499
							output: 30
							thoughts: 10

Thoughts:

Okay, here's my attempt at summarizing that thought process, keeping in mind I'm speaking to a fellow expert:

**Let's Dig into `XFS_FS`**

Right, time to get to the core. Let's see... the initial directive is vague, but the clear next step is to drill down into `XFS_FS`. This likely means we're dealing with an XFS filesystem-related problem or investigation. So, that's where I'll direct my focus. I need to understand what's relevant to XFS in this context and gather the key data. This could involve looking at specific commands, logs, potential error messages, or kernel dumps, depending on what the bigger picture turns out to be. My immediate goal is to establish a solid baseline for the issue. From there, I can pivot to the relevant area based on what is available.

82/2

2026/09/19 01:41

tool

grepper

Args:

{
  "Expression": "config XFS_FS",
  "PathPrefix": "fs/xfs/"
}

Results:

{
  "Output": "fs/xfs/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/xfs/Kconfig:2:config XFS_FS\nfs/xfs/Kconfig-3-\ttristate \"XFS filesystem support\"\n"
}

83/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 66798
							output: 33
							thoughts: 10

Thoughts:

Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue:

**Checking `GPIO_CDEV`**

Alright, time to dive in. My initial thought process, as I scan the landscape, is a direct and focused query: "Let's check `GPIO_CDEV`". No need for preamble; I'm assuming that the user understands the context and the problem space we're working within. `GPIO_CDEV` is likely a key piece, and a logical starting point in diagnosing whatever issue is at hand. This is more of a mental checklist item than a fully formed hypothesis, but it represents the first step in a diagnostic process. I am going to check the basics and then look for any oddities.

84/2

2026/09/19 01:41

tool

read-file

Args:

{
  "File": "drivers/gpio/Kconfig",
  "FirstLine": 80,
  "LineCount": 25
}

Results:

{
  "Contents": "  80:\t\t  Say Y here if you want to enable the legacy, global GPIO\n  81:\t\t  numberspace-based functionalities of the sysfs interface.\n  82:\t\n  83:\tconfig GPIO_CDEV\n  84:\t\tbool \"Character device (/dev/gpiochipN) support\" if EXPERT\n  85:\t\tdefault y\n  86:\t\thelp\n  87:\t\t  Say Y here to add the character device /dev/gpiochipN interface\n  88:\t\t  for GPIOs. The character device allows userspace to control GPIOs\n  89:\t\t  using ioctl() operations.\n  90:\t\n  91:\t\t  Only say N if you are sure that the GPIO character device is not\n  92:\t\t  required.\n  93:\t\n  94:\t\t  If unsure, say Y.\n  95:\t\n  96:\tconfig GPIO_CDEV_V1\n  97:\t\tbool \"Support GPIO ABI Version 1\"\n  98:\t\tdepends on GPIO_CDEV\n  99:\t\thelp\n 100:\t\t  Say Y here to support version 1 of the GPIO CDEV ABI.\n 101:\t\n 102:\t\t  This ABI version is deprecated.\n 103:\t\t  Please use the latest ABI for new developments.\n 104:\t\n"
}

85/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 67347
							output: 20
							thoughts: 1006

Thoughts:

**Refining the Target Symbol List**

Okay, let's nail down these focus symbols. The goal is to pinpoint functions that are directly touched by the changes, and are not part of general hotpaths that could introduce too much noise. We need to avoid ubiquitous code like memory allocators or page fault handlers. Ideally, the symbols will be reachable, non-static, and located within the altered `.c` files.

So, here are the original candidates: `receive_fd`, `scm_recv_one_fd`, `bpf_token_create`, `bpf_iter_new_fd`, `xfs_open_by_handle`, `handshake_nl_accept_doit`, `media_request_alloc`, `ntsync_obj_get_fd`, `new_userfaultfd`, and `do_eventfd`.

But I need to double-check those static functions. `ntsync_obj_get_fd` is static within `ntsync.c`, so that's out. Instead, I should be looking at the direct ioctl entry points within `ntsync.c`, which are `ntsync_char_ioctl`, `ntsync_create_sem`, `ntsync_create_mutex`, and `ntsync_create_event`! That's more specific.

Similarly, `new_userfaultfd` isn't ideal. Let's see... `userfaultfd_open`, or `__do_sys_userfaultfd`, or `userfaultfd_dev_ioctl` in `mm/userfaultfd.c` looks better.

Ah, and I see now, `do_epoll_create` is static in `fs/eventpoll.c`, and called by `__do_sys_epoll_create1` and `__do_sys_epoll_create`.

And `__do_sys_fsmount` and `__do_sys_open_tree_attr` look good too.

Plus, I found `kcm_ioctl` in `net/kcm/kcmsock.c`.

Okay, taking stock: `receive_fd`, `scm_recv_one_fd`, `bpf_token_create`, `bpf_iter_new_fd`, `xfs_open_by_handle`, `handshake_nl_accept_doit`, and `media_request_alloc` are still the best initial choices, as these directly exercise the `FD_PREPARE` and `fd_publish` logic, plus they're addressable kernel symbols. `kcm_ioctl`, and `__do_sys_open_tree_attr` / `__do_sys_fsmount` also seem very promising.

So, let's also verify that we have the correct enable configs. I'm thinking: `BPF_SYSCALL`, `USERFAULTFD`, `NTSYNC`, `AF_KCM`, `XFS_FS`, `NET_HANDSHAKE`, `MEDIA_CONTROLLER`, `MEDIA_SUPPORT`, `GPIO_CDEV`, `GPIO_CDEV_V1`, and `IO_URING_MOCK_FILE`.

Now, let's quickly check `NET_HANDSHAKE`. I recall seeing it in `net/Kconfig`, but it seems like it's a hidden config, meaning it's likely pulled in by other configs, like maybe `SUNRPC`. I should check what actually enables it, just to be sure.

86/2

2026/09/19 01:41

tool

grepper

Args:

{
  "Expression": "select NET_HANDSHAKE"
}

Results:

{
  "Output": "drivers/nvme/host/Kconfig=100=config NVME_TCP_TLS\n--\ndrivers/nvme/host/Kconfig-102-\tdepends on NVME_TCP\ndrivers/nvme/host/Kconfig:103:\tselect NET_HANDSHAKE\ndrivers/nvme/host/Kconfig-104-\tselect KEYS\n--\ndrivers/nvme/target/Kconfig=97=config NVME_TARGET_TCP_TLS\n--\ndrivers/nvme/target/Kconfig-99-\tdepends on NVME_TARGET_TCP\ndrivers/nvme/target/Kconfig:100:\tselect NET_HANDSHAKE\ndrivers/nvme/target/Kconfig-101-\tselect TLS\n"
}

87/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 69309
							output: 29
							thoughts: 51

Thoughts:

**Investigating `SUNRPC` Dependencies**

Okay, so I'm digging into `SUNRPC` again. Time to see what's relying on it within the `net/` directory. Let's start by looking at what configurations might depend on `SUNRPC` itself. There are a few possibilities that jump out at me - `NVME_TCP_TLS`, `NVME_TARGET_TCP_TLS`, and of course, `SUNRPC` itself. Best to zero in on that last one first, as it's the most obvious starting point for an understanding of its integration. Time to pull up the relevant code and see how `SUNRPC` is being utilized.

88/2

2026/09/19 01:41

tool

grepper

Error:

no matches

Args:

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

Results:

{
  "error": "no matches"
}

89/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 69546
							output: 30
							thoughts: 47

Thoughts:

**Decision Time: Network Security for SUNRPC**

Okay, so I'm trying to figure out the best approach for securing my `SUNRPC` communication. The question is, do I go with `SUNRPC_XPRT_RDMA` or `RPCSEC_GSS_KRB5`? Both have their advantages and disadvantages, depending on the specific environment and requirements. To make an informed decision, I need to understand how these options handle the network handshake.

My gut tells me a quick `grepper` search within the `net/sunrpc` directory should give me some insights into how `NET_HANDSHAKE` is implemented in relation to these two choices. Hopefully, I'll find some code examples or documentation that clarifies the connection establishment process for each. This should help me assess which method is more suitable based on the relevant context. I'll need to look for any clues about how this impacts performance, security posture, and compatibility with my existing infrastructure. Let's dig in.

90/2

2026/09/19 01:41

tool

grepper

Error:

no matches

Args:

{
  "Expression": "HANDSHAKE",
  "PathPrefix": "net/sunrpc/Kconfig"
}

Results:

{
  "error": "no matches"
}

91/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 69847
							output: 27
							thoughts: 20

Thoughts:

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

**Investigating Network Handshake Configuration Options**

Alright, I need to get a handle on how network handshake features are configured within this build system. The best first step is always to go straight to the source, the `Kconfig` files. I'm going to leverage `grep` to quickly search through the entire configuration tree for anything related to "NET_HANDSHAKE". This should give me a comprehensive overview of the available options, dependencies, and default settings related to network handshaking, whether it's TCP/IP negotiation, TLS setup, or something more specialized within this particular domain. I'm expecting this will quickly expose the relevant configuration symbols and their associated help text, which will provide a great foundation to understand the implementation and make future decisions about its customization.

92/2

2026/09/19 01:41

tool

grepper

Args:

{
  "Expression": "NET_HANDSHAKE",
  "PathPrefix": "net/"
}

Results:

{
  "Output": "net/Kconfig=92=source \"net/xdp/Kconfig\"\nnet/Kconfig-93-\nnet/Kconfig:94:config NET_HANDSHAKE\nnet/Kconfig-95-\tbool\n--\nnet/Kconfig-98-\nnet/Kconfig:99:config NET_HANDSHAKE_KUNIT_TEST\nnet/Kconfig-100-\ttristate \"KUnit tests for the handshake upcall mechanism\" if !KUNIT_ALL_TESTS\n--\nnet/Makefile=75=obj-$(CONFIG_MCTP)\t\t+= mctp/\nnet/Makefile:76:obj-$(CONFIG_NET_HANDSHAKE)\t+= handshake/\nnet/Makefile-77-obj-$(CONFIG_NET_SHAPER)\t+= shaper/\n--\nnet/handshake/.kunitconfig=9=CONFIG_SUNRPC=y\nnet/handshake/.kunitconfig:10:CONFIG_NET_HANDSHAKE=y\nnet/handshake/.kunitconfig:11:CONFIG_NET_HANDSHAKE_KUNIT_TEST=y\n--\nnet/handshake/Makefile=11=handshake-y := alert.o genl.o netlink.o request.o tlshd.o trace.o\nnet/handshake/Makefile-12-\nnet/handshake/Makefile:13:obj-$(CONFIG_NET_HANDSHAKE_KUNIT_TEST) += handshake-test.o\n"
}

93/2

2026/09/19 01:41

llm

patch-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 70427
							output: 319
							thoughts: 588

Thoughts:

**My Analysis of Configuration and Reasoning**

Okay, let's break this down. First, I see that `NET_HANDSHAKE` is selected either by `NVME_TCP_TLS` or `NVME_TARGET_TCP_TLS`. `NET_HANDSHAKE` itself can be configured directly or via `NVME_TCP_TLS`. Got it.

Next, I'm checking some dependencies. `IO_URING_MOCK_FILE` relies on both `IO_URING` and `EXPERT`, which makes perfect sense. `NTSYNC` is independent – no dependencies there. `AF_KCM` requires `INET`, which is expected. `GPIO_CDEV` is interesting; it has a prompt controlled by `EXPERT` and depends on `GPIOLIB`. Good to know the potential expert interaction. `MEDIA_CONTROLLER` depends on `MEDIA_SUPPORT`, as I'd anticipate.

Now, a quick scan of the `FocusSymbols`. I see a variety of file descriptor related operations, `bpf`, `xfs`, `media`, `handshake` and `ntsync` functions. The list looks comprehensive.

Now to the `EnableConfigs`. The key ones are `BPF_SYSCALL`, `USERFAULTFD`, `NTSYNC`, `AF_KCM`, `XFS_FS`, `NET_HANDSHAKE`, and some media and GPIO configs. This seems like a broad selection covering several areas.

Finally, the reasoning behind the patch is about RAII cleanup mechanism changes in `include/linux/file.h`. It's a refactoring of `fd_prepare`, `fd_publish`, and `FD_ADD` macros, and the underlying struct layout. This touches file descriptor management, specifically inlining and error reporting. Because of the broad implications, this is high risk with implications for resource management and syscall error paths. Therefore, fuzzing is required to verify the changes prevent memory leaks, double-puts, and regressions across different core subsystems, like VFS, BPF, networking, memory management, and character devices.

Excellent. Everything here is aligned and logical. No conflicts or inconsistencies are apparent. I am completely confident to `set-results`.

94/2

2026/09/19 01:41

tool

set-results

Args:

{
  "EnableConfigs": [
    "BPF_SYSCALL",
    "USERFAULTFD",
    "NTSYNC",
    "AF_KCM",
    "XFS_FS",
    "NET_HANDSHAKE",
    "MEDIA_SUPPORT",
    "MEDIA_CONTROLLER",
    "GPIOLIB",
    "GPIO_CDEV",
    "GPIO_CDEV_V1"
  ],
  "FocusSymbols": [
    "receive_fd",
    "scm_recv_one_fd",
    "bpf_iter_new_fd",
    "bpf_token_create",
    "xfs_open_by_handle",
    "media_request_alloc",
    "handshake_nl_accept_doit",
    "kcm_ioctl",
    "ntsync_obj_get_fd"
  ],
  "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.",
  "WorthFuzzing": true
}

Results:

{
  "EnableConfigs": [
    "BPF_SYSCALL",
    "USERFAULTFD",
    "NTSYNC",
    "AF_KCM",
    "XFS_FS",
    "NET_HANDSHAKE",
    "MEDIA_SUPPORT",
    "MEDIA_CONTROLLER",
    "GPIOLIB",
    "GPIO_CDEV",
    "GPIO_CDEV_V1"
  ],
  "FocusSymbols": [
    "receive_fd",
    "scm_recv_one_fd",
    "bpf_iter_new_fd",
    "bpf_token_create",
    "xfs_open_by_handle",
    "media_request_alloc",
    "handshake_nl_accept_doit",
    "kcm_ioctl",
    "ntsync_obj_get_fd"
  ],
  "Reasoning": "The patch refactors the fd_prepare resource cleanup guard and related helper macros (FD_PREPARE, fd_publish, FD_ADD) in include/linux/file.h, changing the struct definition, error handling conventions (checking fdf-\u003efd \u003c 0 instead of fdf.err), and scope cleanup logic across core VFS, BPF, networking, userfaultfd, and various driver endpoints on amd64. Fuzzing is necessary to ensure the modified cleanup and publishing logic properly handles error unwind paths without leaking file descriptors, leaking file struct references, or causing double-free issues.",
  "WorthFuzzing": true
}

95/1

2026/09/19 01:41

action

Args:

{
  "WorthFuzzing": true
}

Results:

null

96/2

2026/09/19 01:41

agent

kmsan-evaluator

Model:

core

Args:

null

Results:

{
  "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

Instruction:

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

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

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

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

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

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

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


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

Prompt:

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit 58a61ff73c4736b57ba577d0b474d08304b94c83
Author: syz-cluster <triage@syzkaller.com>
Date:   Sat Sep 19 01:36:27 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 2b54afb31529f..5c06f69c9f7f9 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -266,9 +266,9 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
 static int spufs_context_open(const struct path *path)
 {
 	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	if (fdf.err)
-		return fdf.err;
-	fd_prepare_file(fdf)->f_op = &spufs_context_fops;
+	if (fdf->fd < 0)
+		return fdf->fd;
+	fdf->file->f_op = &spufs_context_fops;
 	return fd_publish(fdf);
 }
 
@@ -499,9 +499,9 @@ static int spufs_gang_open(const struct path *path)
 	 * in error path of *_open().
 	 */
 	FD_PREPARE(fdf, 0, dentry_open(path, O_RDONLY, current_cred()));
-	if (fdf.err)
-		return fdf.err;
-	fd_prepare_file(fdf)->f_op = &spufs_gang_fops;
+	if (fdf->fd < 0)
+		return fdf->fd;
+	fdf->file->f_op = &spufs_gang_fops;
 	return fd_publish(fdf);
 }
 
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 9f3b628d57934..6526ce27ea446 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -377,11 +377,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-linehandle", &linehandle_fileops,
 				      lh, O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(lh);
 
-	handlereq.fd = fd_prepare_fd(fdf);
+	handlereq.fd = fdf->fd;
 	if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
 		return -EFAULT;
 
@@ -1715,11 +1715,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-line", &line_fileops, lr,
 				      O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(lr);
 
-	ulr.fd = fd_prepare_fd(fdf);
+	ulr.fd = fdf->fd;
 	if (copy_to_user(ip, &ulr, sizeof(ulr)))
 		return -EFAULT;
 
@@ -2115,11 +2115,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
 		   anon_inode_getfile("gpio-event", &lineevent_fileops, le,
 				      O_RDONLY | O_CLOEXEC));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	retain_and_null_ptr(le);
 
-	eventreq.fd = fd_prepare_fd(fdf);
+	eventreq.fd = fdf->fd;
 	if (copy_to_user(ip, &eventreq, sizeof(eventreq)))
 		return -EFAULT;
 
diff --git a/drivers/gpu/drm/msm/msm_perfcntr.c b/drivers/gpu/drm/msm/msm_perfcntr.c
index ce65b1160955e..7fa2e858bd082 100644
--- a/drivers/gpu/drm/msm/msm_perfcntr.c
+++ b/drivers/gpu/drm/msm/msm_perfcntr.c
@@ -543,8 +543,8 @@ msm_ioctl_perfcntr_config(struct drm_device *dev, void *data, struct drm_file *f
 
 		FD_PREPARE(fdf, O_CLOEXEC,
 			   anon_inode_getfile("[msm_perfcntrs]", &stream_fops, stream, 0));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 
 		INIT_WORK(&stream->sel_work, sel_worker);
 		kthread_init_work(&stream->sample_work, sample_worker);
diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c
index 13e77648807c2..e1387f039780b 100644
--- a/drivers/media/mc/mc-request.c
+++ b/drivers/media/mc/mc-request.c
@@ -316,15 +316,15 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   anon_inode_getfile("request", &request_fops, NULL,
 				      O_CLOEXEC));
-	if (fdf.err) {
-		ret = fdf.err;
+	if (fdf->fd < 0) {
+		ret = fdf->fd;
 		goto err_free_req;
 	}
 
-	fd_prepare_file(fdf)->private_data = req;
+	fdf->file->private_data = req;
 
 	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
-		 atomic_inc_return(&mdev->request_id), fd_prepare_fd(fdf));
+		 atomic_inc_return(&mdev->request_id), fdf->fd);
 	atomic_inc(&mdev->num_requests);
 	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
 
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 4a805919bb0c5..2857ae37d3c81 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -724,9 +724,9 @@ static int ntsync_obj_get_fd(struct ntsync_obj *obj)
 {
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR));
-	if (fdf.err)
-		return fdf.err;
-	obj->file = fd_prepare_file(fdf);
+	if (fdf->fd < 0)
+		return fdf->fd;
+	obj->file = fdf->file;
 	return fd_publish(fdf);
 }
 
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 9d33a02757d52..52426795752ec 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -403,8 +403,8 @@ static int do_eventfd(unsigned int count, int flags)
 	FD_PREPARE(fdf, flags,
 		   anon_inode_getfile_fmode("[eventfd]", &eventfd_fops, ctx,
 					    flags, FMODE_NOWAIT));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	ctx->id = ida_alloc(&eventfd_ida, GFP_KERNEL);
 	retain_and_null_ptr(ctx);
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index e0c4bf88a8383..f48b829a710f7 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2514,11 +2514,11 @@ static int do_epoll_create(int flags)
 	FD_PREPARE(fdf, O_RDWR | (flags & O_CLOEXEC),
 		   anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
 				      O_RDWR | (flags & O_CLOEXEC)));
-	if (fdf.err) {
+	if (fdf->fd < 0) {
 		ep_clear_and_put(ep);
-		return fdf.err;
+		return fdf->fd;
 	}
-	ep->file = fd_prepare_file(fdf);
+	ep->file = fdf->file;
 	return fd_publish(fdf);
 }
 
diff --git a/fs/file.c b/fs/file.c
index 628ca07dc4b17..2a01b22eb65a1 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -1391,17 +1391,17 @@ int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
 		return error;
 
 	FD_PREPARE(fdf, o_flags, file);
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 	get_file(file);
 
 	if (ufd) {
-		error = put_user(fd_prepare_fd(fdf), ufd);
+		error = put_user(fdf->fd, ufd);
 		if (error)
 			return error;
 	}
 
-	__receive_sock(fd_prepare_file(fdf));
+	__receive_sock(fdf->file);
 	return fd_publish(fdf);
 }
 EXPORT_SYMBOL_GPL(receive_fd);
diff --git a/fs/namespace.c b/fs/namespace.c
index 1ecd96c918b33..0f5c00816775b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4544,16 +4544,16 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 
 	FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0,
 		   dentry_open(&new_path, O_PATH, fc->cred));
-	if (fdf.err) {
+	if (fdf->fd < 0) {
 		dissolve_on_fput(new_path.mnt);
-		return fdf.err;
+		return fdf->fd;
 	}
 
 	/*
 	 * Attach to an apparent O_PATH fd with a note that we
 	 * need to unmount it, not just simply put it.
 	 */
-	fd_prepare_file(fdf)->f_mode |= FMODE_NEED_UNMOUNT;
+	fdf->file->f_mode |= FMODE_NEED_UNMOUNT;
 	return fd_publish(fdf);
 }
 
@@ -5198,12 +5198,12 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename,
 		return -EINVAL;
 
 	FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	if (uattr) {
 		struct mount_kattr kattr = {};
-		struct file *file = fd_prepare_file(fdf);
+		struct file *file = fdf->file;
 		int ret;
 
 		if (flags & OPEN_TREE_CLONE)
diff --git a/fs/nsfs.c b/fs/nsfs.c
index c3b6ae76594a8..56ea0bb9ef3a3 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -348,8 +348,8 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
 			return ret;
 
 		FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 		/*
 		 * If @uinfo is passed return all information about the
 		 * mount namespace as well.
diff --git a/fs/xfs/xfs_handle.c b/fs/xfs/xfs_handle.c
index 0689cade8f74c..303bcff644596 100644
--- a/fs/xfs/xfs_handle.c
+++ b/fs/xfs/xfs_handle.c
@@ -272,11 +272,11 @@ xfs_open_by_handle(
 	path.mnt = mntget(parfilp->f_path.mnt);
 
 	FD_PREPARE(fdf, 0, dentry_open(&path, hreq->oflags, cred));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	if (S_ISREG(inode->i_mode)) {
-		struct file *filp = fd_prepare_file(fdf);
+		struct file *filp = fdf->file;
 
 		filp->f_flags |= O_NOATIME;
 		filp->f_mode |= FMODE_NOCMTIME;
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index b1b5698cbf1b6..1fb8058b897d4 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -261,10 +261,6 @@ const volatile void * __must_check_fn(const volatile void *val)
  * CLASS(name, var)(args...):
  *	declare the variable @var as an instance of the named class
  *
- * CLASS_INIT(name, var, init_expr):
- *	declare the variable @var as an instance of the named class with
- *	custom initialization expression.
- *
  * Ex.
  *
  * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd)
@@ -302,9 +298,6 @@ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_
 	class_##_name##_t var __cleanup(class_##_name##_destructor) =	\
 		class_##_name##_constructor
 
-#define CLASS_INIT(_name, _var, _init_expr)                             \
-        class_##_name##_t _var __cleanup(class_##_name##_destructor) = (_init_expr)
-
 #define __scoped_class(_name, var, _label, args...)        \
 	for (CLASS(_name, var)(args); ; ({ goto _label; })) \
 		if (0) {                                   \
diff --git a/include/linux/file.h b/include/linux/file.h
index 27484b444d315..41c3c0be10644 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -12,6 +12,7 @@
 #include <linux/errno.h>
 #include <linux/cleanup.h>
 #include <linux/err.h>
+#include <linux/vfsdebug.h>
 
 struct file;
 
@@ -129,117 +130,84 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
 
 /*
  * fd_prepare: Combined fd + file allocation cleanup class.
- * @err: Error code to indicate if allocation succeeded.
- * @__fd: Allocated fd (may not be accessed directly)
- * @__file: Allocated struct file pointer (may not be accessed directly)
+ * @fd: Allocated fd
+ * @file: Allocated struct file pointer
  *
  * Allocates an fd and a file together. On error paths, automatically cleans
  * up whichever resource was successfully allocated. Allows flexible file
  * allocation with different functions per usage.
  *
- * Do not use directly.
+ * Do not declare directly, use FD_PREPARE().
  */
 struct fd_prepare {
-	s32 err;
-	s32 __fd; /* do not access directly */
-	struct file *__file; /* do not access directly */
+	int fd;
+	struct file *file;
 };
 
-/* Typedef for fd_prepare cleanup guards. */
-typedef struct fd_prepare class_fd_prepare_t;
-
-/*
- * Accessors for fd_prepare class members.
- * _Generic() is used for zero-cost type safety.
- */
-#define fd_prepare_fd(_fdf) \
-	(_Generic((_fdf), struct fd_prepare: (_fdf).__fd))
-
-#define fd_prepare_file(_fdf) \
-	(_Generic((_fdf), struct fd_prepare: (_fdf).__file))
-
 /* Do not use directly. */
-static inline void class_fd_prepare_destructor(const struct fd_prepare *fdf)
+static __always_inline void __fd_prepare_cleanup(const struct fd_prepare *fdf)
 {
-	if (unlikely(fdf->__fd >= 0))
-		put_unused_fd(fdf->__fd);
-	if (unlikely(!IS_ERR_OR_NULL(fdf->__file)))
-		fput(fdf->__file);
+	if (unlikely(fdf->fd >= 0)) {
+		put_unused_fd(fdf->fd);
+		fput(fdf->file);
+	}
 }
 
 /* Do not use directly. */
-static inline int class_fd_prepare_lock_err(const struct fd_prepare *fdf)
+static __always_inline struct fd_prepare __fd_prepare(int fd, struct file *file)
 {
-	if (unlikely(fdf->err))
-		return fdf->err;
-	if (unlikely(fdf->__fd < 0))
-		return fdf->__fd;
-	if (unlikely(IS_ERR(fdf->__file)))
-		return PTR_ERR(fdf->__file);
-	if (unlikely(!fdf->__file))
-		return -ENOMEM;
-	return 0;
+	if (fd >= 0 && IS_ERR_OR_NULL(file)) {
+		int err = file ? PTR_ERR(file) : -ENOMEM;
+
+		put_unused_fd(fd);
+		fd = err;
+		file = NULL;
+	}
+	return (struct fd_prepare){ .fd = fd, .file = file };
 }
 
 /*
- * __FD_PREPARE_INIT - Helper to initialize fd_prepare class.
- * @_fd_flags: flags for get_unused_fd_flags()
- * @_file_owned: expression that returns struct file *
- *
- * Returns a struct fd_prepare with fd, file, and err set.
- * If fd allocation fails, fd will be negative and err will be set. If
- * fd succeeds but file_init_expr fails, file will be ERR_PTR and err
- * will be set. The err field is the single source of truth for error
- * checking.
- */
-#define __FD_PREPARE_INIT(_fd_flags, _file_owned)                 \
-	({                                                        \
-		struct fd_prepare fdf = {                         \
-			.__fd = get_unused_fd_flags((_fd_flags)), \
-		};                                                \
-		if (likely(fdf.__fd >= 0))                        \
-			fdf.__file = (_file_owned);               \
-		fdf.err = ACQUIRE_ERR(fd_prepare, &fdf);          \
-		fdf;                                              \
-	})
-
-/*
- * FD_PREPARE - Macro to declare and initialize an fd_prepare variable.
+ * FD_PREPARE - Declare and initialize an fd_prepare instance.
  *
- * Declares and initializes an fd_prepare variable with automatic
- * cleanup. No separate scope required - cleanup happens when variable
- * goes out of scope.
+ * This allocates a new fd and only evaluates @_file_owned if the
+ * allocation succeeded. Cleanup happens when the variable goes out of
+ * scope and the guard releases whichever of the descriptor and the file
+ * was allocated. If fd_publish() was called the fd and file are
+ * published and cleanup becomes a nop.
  *
- * @_fdf: name of struct fd_prepare variable to define
+ * @_fdf: name of the const struct fd_prepare pointer to define
  * @_fd_flags: flags for get_unused_fd_flags()
  * @_file_owned: struct file to take ownership of (can be expression)
  */
+#define __FD_PREPARE(_guard, _fdf, _fd_flags, _file_owned)		\
+	struct fd_prepare _guard __cleanup(__fd_prepare_cleanup) = ({	\
+		int __fd = get_unused_fd_flags(_fd_flags);		\
+		__fd_prepare(__fd, __fd < 0 ? NULL : (_file_owned));	\
+	});								\
+	const struct fd_prepare *const _fdf = &_guard
+
 #define FD_PREPARE(_fdf, _fd_flags, _file_owned) \
-	CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))
+	__FD_PREPARE(__UNIQUE_ID(fd_prepare), _fdf, _fd_flags, _file_owned)
 
 /*
  * fd_publish - Publish prepared fd and file to the fd table.
- * @_fdf: struct fd_prepare variable
+ * @fdf: struct fd_prepare pointer defined by FD_PREPARE()
  */
-#define fd_publish(_fdf)                                       \
-	({                                                     \
-		struct fd_prepare *fdp = &(_fdf);              \
-		VFS_WARN_ON_ONCE(fdp->err);                    \
-		VFS_WARN_ON_ONCE(fdp->__fd < 0);               \
-		VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \
-		fd_install(fdp->__fd, fdp->__file);            \
-		retain_and_null_ptr(fdp->__file);              \
-		take_fd(fdp->__fd);                            \
-	})
+static __always_inline int fd_publish(const struct fd_prepare *fdf)
+{
+	/* Callers only get a const view, the guard itself is writable. */
+	struct fd_prepare *guard = (struct fd_prepare *)fdf;
+
+	VFS_WARN_ON_ONCE(guard->fd < 0);
+	fd_install(guard->fd, guard->file);
+	return take_fd(guard->fd);
+}
 
 /* Do not use directly. */
-#define __FD_ADD(_fdf, _fd_flags, _file_owned)            \
-	({                                                \
-		FD_PREPARE(_fdf, _fd_flags, _file_owned); \
-		s32 ret = _fdf.err;                       \
-		if (likely(!ret))                         \
-			ret = fd_publish(_fdf);           \
-		ret;                                      \
+#define __FD_ADD(_fdf, _fd_flags, _file_owned)			\
+	({							\
+		FD_PREPARE(_fdf, _fd_flags, _file_owned);	\
+		_fdf->fd < 0 ? _fdf->fd : fd_publish(_fdf);	\
 	})
 
 /*
diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c
index b318ed697998e..9f0b4d850c12f 100644
--- a/io_uring/mock_file.c
+++ b/io_uring/mock_file.c
@@ -257,17 +257,17 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
 	FD_PREPARE(fdf, O_RDWR | O_CLOEXEC,
 		   anon_inode_create_getfile("[io_uring_mock]", fops, mf,
 					     O_RDWR | O_CLOEXEC, NULL));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	retain_and_null_ptr(mf);
-	file = fd_prepare_file(fdf);
+	file = fdf->file;
 	file->f_mode |= FMODE_READ | FMODE_CAN_READ | FMODE_WRITE |
 			FMODE_CAN_WRITE | FMODE_LSEEK;
 	if (mc.flags & IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)
 		file->f_mode |= FMODE_NOWAIT;
 
-	mc.out_fd = fd_prepare_fd(fdf);
+	mc.out_fd = fdf->fd;
 	if (copy_to_user(uarg, &mc, uarg_size))
 		return -EFAULT;
 
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 14a5fdfa04214..5f790d12f72e1 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -643,11 +643,11 @@ int bpf_iter_new_fd(struct bpf_link *link)
 	flags = O_RDONLY | O_CLOEXEC;
 
 	FD_PREPARE(fdf, flags, anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	iter_link = container_of(link, struct bpf_iter_link, link);
-	err = prepare_seq_file(fd_prepare_file(fdf), iter_link);
+	err = prepare_seq_file(fdf->file, iter_link);
 	if (err)
 		return err; /* Automatic cleanup handles fput */
 
diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c
index e85a179523f02..da915a4f972b1 100644
--- a/kernel/bpf/token.c
+++ b/kernel/bpf/token.c
@@ -169,8 +169,8 @@ int bpf_token_create(union bpf_attr *attr)
 	FD_PREPARE(fdf, O_CLOEXEC,
 		   alloc_file_pseudo(inode, path.mnt, BPF_TOKEN_INODE_NAME,
 				     O_RDWR, &bpf_token_fops));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	token = kzalloc_obj(*token, GFP_USER);
 	if (!token)
@@ -190,7 +190,7 @@ int bpf_token_create(union bpf_attr *attr)
 		return err;
 
 	get_user_ns(token->userns);
-	fd_prepare_file(fdf)->private_data = no_free_ptr(token);
+	fdf->file->private_data = no_free_ptr(token);
 	return fd_publish(fdf);
 }
 
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 23fb68fce000e..ea382aedfc90d 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -4809,12 +4809,12 @@ static int new_userfaultfd(int flags)
 		   anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
 					     O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS),
 					     NULL));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
 	/* prevent the mm struct to be freed */
 	mmgrab(ctx->mm);
-	fd_prepare_file(fdf)->f_mode |= FMODE_NOWAIT;
+	fdf->file->f_mode |= FMODE_NOWAIT;
 	retain_and_null_ptr(ctx);
 	return fd_publish(fdf);
 }
diff --git a/net/core/scm.c b/net/core/scm.c
index f0d44ecdb11fc..15c330784a699 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -364,14 +364,14 @@ int scm_recv_one_fd(struct file *f, int __user *ufd, unsigned int flags,
 		return notrunc ? put_user(error, ufd) : error;
 
 	FD_PREPARE(fdf, flags, get_file(f));
-	if (fdf.err)
-		return fdf.err;
+	if (fdf->fd < 0)
+		return fdf->fd;
 
-	error = put_user(fd_prepare_fd(fdf), ufd);
+	error = put_user(fdf->fd, ufd);
 	if (error)
 		return error;
 
-	__receive_sock(fd_prepare_file(fdf));
+	__receive_sock(fdf->file);
 	return fd_publish(fdf);
 }
 
diff --git a/net/handshake/netlink.c b/net/handshake/netlink.c
index 3fd4fef9bab1a..73b8314d9010c 100644
--- a/net/handshake/netlink.c
+++ b/net/handshake/netlink.c
@@ -107,17 +107,17 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 	req = handshake_req_next(hn, class);
 	if (req) {
 		FD_PREPARE(fdf, O_CLOEXEC, req->hr_file);
-		if (fdf.err) {
+		if (fdf->fd < 0) {
 			fput(req->hr_file); /* drop ref from handshake_req_next() */
-			err = fdf.err;
+			err = fdf->fd;
 			goto out_complete;
 		}
 
-		err = req->hr_proto->hp_accept(req, info, fd_prepare_fd(fdf));
+		err = req->hr_proto->hp_accept(req, info, fdf->fd);
 		if (err)
 			goto out_complete; /* Automatic cleanup handles fput */
 
-		trace_handshake_cmd_accept(net, req, req->hr_sk, fd_prepare_fd(fdf));
+		trace_handshake_cmd_accept(net, req, req->hr_sk, fdf->fd);
 		fd_publish(fdf);
 		return 0;
 	}
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 71af69d442f21..962ee2c4acd2f 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1580,10 +1580,10 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct kcm_clone info;
 
 		FD_PREPARE(fdf, 0, kcm_clone(sock));
-		if (fdf.err)
-			return fdf.err;
+		if (fdf->fd < 0)
+			return fdf->fd;
 
-		info.fd = fd_prepare_fd(fdf);
+		info.fd = fdf->fd;
 		if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 			return -EFAULT;

97/3

2026/09/19 01:41

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 10927
							output: 30
							thoughts: 709

Thoughts:

**KMSAN Fuzzing Justification: A Deep Dive**

Okay, so I need to decide if this patch series warrants a dedicated KMSAN fuzzing run, or if the standard KASAN fuzzing is sufficient. Given my expertise, I'm going to take a methodical approach. It looks like this patch touches `FD_PREPARE`, `fd_prepare`, `fd_publish`, and related callers – all pretty critical areas within the kernel's file descriptor handling. Specifically, it seems like the changes are in `include/linux/file.h`.

I see there's a struct change. The `fd_prepare` struct has been modified significantly. It looks like the old struct had some 'hidden' fields like `__fd` and `__file` and there's a new cleanup function (`__fd_prepare_cleanup`) as well as some new helper functions: `__fd_prepare`, and macros: `__FD_PREPARE`, `FD_PREPARE`. The structure of the prepare call looks different. I have to understand the context of this to see if the changes are going to impact memory use.

I need to understand what `fd_publish` is doing, as it's the interface to how the guard struct is working. And, critically, it calls `take_fd`. This function, along with the cleanup and prepare, are all key to understanding this. The new `fd_publish` function uses this new struct, which means this could have significant impacts. The potential for memory issues is increased by the nature of the operations here.

So, I'm going to track down what the `take_fd` function does, and how the cleanup works, because that's what's going to tell me if this patch is a prime candidate for a dedicated KMSAN run. A quick `grepper` search for `take_fd` will be the next step to reveal what's going on behind the scenes here. I need to fully understand how file descriptors are being managed and released in this context to determine the memory safety implications. If this is changing how these are handled, a dedicated KMSAN run might well be justified to catch any potential memory leaks or use-after-free conditions introduced by this refactoring.

98/3

2026/09/19 01:42

tool

grepper

Args:

{
  "Expression": "take_fd",
  "PathPrefix": "include/linux/file.h"
}

Results:

{
  "Output": "include/linux/file.h=98=DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))\n--\ninclude/linux/file.h-100-/*\ninclude/linux/file.h:101: * take_fd() will take care to set @fd to -EBADF ensuring that\ninclude/linux/file.h-102- * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it\n--\ninclude/linux/file.h-115- * fd_install(fd, f);\ninclude/linux/file.h:116: * return take_fd(fd);\ninclude/linux/file.h-117- */\ninclude/linux/file.h:118:#define take_fd(fd) __get_and_null(fd, -EBADF)\ninclude/linux/file.h-119-\n--\ninclude/linux/file.h=196=static __always_inline int fd_publish(const struct fd_prepare *fdf)\n--\ninclude/linux/file.h-202-\tfd_install(guard-\u003efd, guard-\u003efile);\ninclude/linux/file.h:203:\treturn take_fd(guard-\u003efd);\ninclude/linux/file.h-204-}\n"
}

99/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 12478
							output: 39
							thoughts: 603

Thoughts:

**Analyzing a Potential File Descriptor Leak**

Okay, so I'm looking at this code and trying to follow the logic. `take_fd(guard->fd)` seems to be setting `guard->fd` to `-EBADF` and returning the previous file descriptor. That `-EBADF` assignment is key.

Then, `__fd_prepare_cleanup` comes into play. It checks if `fdf->fd >= 0`. If `guard->fd` *was* set to `-EBADF` (and therefore `< 0`), the condition is false. That means `put_unused_fd` and `fput` won't be called. That's the cleanup part I need to pay attention to!

Now, the changes in the callers look interesting. Before, the code checked for `fdf.err` but the new code checks `fdf->fd < 0`, and the handling differs a bit. It’s checking the error code of `fd` directly.

Wait a second...I'm getting a little worried. This is where it gets interesting. I need to dive deeper. Let's look at `kcm_ioctl` in `net/kcm/kcmsock.c`. I see they're using `FD_PREPARE`. Now, the error checking changed from the previous approach where we checked the `err` field. The old way: `if (fdf.err)` to the new: `if (fdf->fd < 0)`.

Aha! `info.fd = fdf->fd;` is the key. The previous code had a function called `fd_prepare_fd`, but now, we're simply assigning the value from `fdf->fd`. And that's what's got me concerned. I see they are copying the `info` structure to userspace via `copy_to_user`.

Here's the problem. Wait! Does `struct kcm_clone info;` have uninitialized fields? It looks like it does. This could be a potential information leak, especially if `kcm_clone` doesn't fully initialize it! I need to investigate the initialization of `kcm_clone` and surrounding code to make sure it's properly handled, specifically in `net/kcm/kcmsock.c` around line 1580! Time to trace back the flow.

100/3

2026/09/19 01:42

tool

read-file

Args:

{
  "File": "net/kcm/kcmsock.c",
  "FirstLine": 1570,
  "LineCount": 35
}

Results:

{
  "Contents": "1570:\t\t\tstruct kcm_unattach info;\n1571:\t\n1572:\t\t\tif (copy_from_user(\u0026info, (void __user *)arg, sizeof(info)))\n1573:\t\t\t\treturn -EFAULT;\n1574:\t\n1575:\t\t\terr = kcm_unattach_ioctl(sock, \u0026info);\n1576:\t\n1577:\t\t\tbreak;\n1578:\t\t}\n1579:\t\tcase SIOCKCMCLONE: {\n1580:\t\t\tstruct kcm_clone info;\n1581:\t\n1582:\t\t\tFD_PREPARE(fdf, 0, kcm_clone(sock));\n1583:\t\t\tif (fdf-\u003efd \u003c 0)\n1584:\t\t\t\treturn fdf-\u003efd;\n1585:\t\n1586:\t\t\tinfo.fd = fdf-\u003efd;\n1587:\t\t\tif (copy_to_user((void __user *)arg, \u0026info, sizeof(info)))\n1588:\t\t\t\treturn -EFAULT;\n1589:\t\n1590:\t\t\tfd_publish(fdf);\n1591:\t\t\terr = 0;\n1592:\t\t\tbreak;\n1593:\t\t}\n1594:\t\tdefault:\n1595:\t\t\terr = -ENOIOCTLCMD;\n1596:\t\t\tbreak;\n1597:\t\t}\n1598:\t\n1599:\t\treturn err;\n1600:\t}\n1601:\t\n1602:\tstatic void release_mux(struct kcm_mux *mux)\n1603:\t{\n1604:\t\tstruct kcm_net *knet = mux-\u003eknet;\n"
}

101/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 14088
							output: 21
							thoughts: 32

Thoughts:

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

**Diving into `kcm_ioctl` and `kcm_clone`**

Okay, hold on a minute. The code's talking about a `struct kcm_clone` in `kcm_ioctl`. Right, let's take a quick look at that `struct`. I need to refresh my memory about its contents and how it interacts with the kernel's ioctl implementation for this subsystem. I'll need to understand the data passed through this struct to assess the issue. Gotta make sure it's all making sense in the context of the larger KCM architecture. What are the key fields? How are they being set and used? Okay, let's get to it.

102/3

2026/09/19 01:42

tool

grepper

Args:

{
  "Expression": "struct kcm_clone\\b"
}

Results:

{
  "Output": "Documentation/networking/kcm.rst=128=a KCM socket. This is accomplished by an ioctl on a KCM socket::\n--\nDocumentation/networking/kcm.rst-130-  /* From linux/kcm.h */\nDocumentation/networking/kcm.rst:131:  struct kcm_clone {\nDocumentation/networking/kcm.rst-132-\tint fd;\n--\nDocumentation/networking/kcm.rst-134-\nDocumentation/networking/kcm.rst:135:  struct kcm_clone info;\nDocumentation/networking/kcm.rst-136-\n--\ninclude/uapi/linux/kcm.h=23=struct kcm_unattach {\n--\ninclude/uapi/linux/kcm.h-26-\ninclude/uapi/linux/kcm.h:27:struct kcm_clone {\ninclude/uapi/linux/kcm.h-28-\tint fd;\n--\nnet/kcm/kcmsock.c=1554=static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)\n--\nnet/kcm/kcmsock.c-1579-\tcase SIOCKCMCLONE: {\nnet/kcm/kcmsock.c:1580:\t\tstruct kcm_clone info;\nnet/kcm/kcmsock.c-1581-\n"
}

103/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 14661
							output: 40
							thoughts: 124

Thoughts:

**Analyzing a Structure and its Usage**

Okay, so this `struct kcm_clone` is really bare-bones; it's just an `int fd;`. Seems pretty straightforward, and that `info.fd = fdf->fd;` initialization is essentially copying the file descriptor. No padding issues to worry about, since the struct is just a single integer. I'm noting that this part was *already* in the code before the patch, which makes the change even less likely to be the root of the problem. Previously, it looked like `info.fd = fd_prepare_fd(fdf)` which was changed to `info.fd = fdf->fd`.

But, hold on a second... what about that `drivers/gpio/gpiolib-cdev.c` file? I need to check out the GPIO functions. Let's see... I'll need to look at `linehandle_create`, `linereq_create`, and `lineevent_create`. Let's see if the file descriptor handling logic has changed in any of those. Time to dive in.

104/3

2026/09/19 01:42

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 365,
  "LineCount": 40
}

Results:

{
  "Contents": " 365:\t\t\t} else if (lflags \u0026 GPIOHANDLE_REQUEST_INPUT) {\n 366:\t\t\t\tret = gpiod_direction_input_nonotify(desc);\n 367:\t\t\t\tif (ret)\n 368:\t\t\t\t\treturn ret;\n 369:\t\t\t}\n 370:\t\n 371:\t\t\tgpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);\n 372:\t\n 373:\t\t\tdev_dbg(\u0026gdev-\u003edev, \"registered chardev handle for line %d\\n\",\n 374:\t\t\t\toffset);\n 375:\t\t}\n 376:\t\n 377:\t\tFD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,\n 378:\t\t\t   anon_inode_getfile(\"gpio-linehandle\", \u0026linehandle_fileops,\n 379:\t\t\t\t\t      lh, O_RDONLY | O_CLOEXEC));\n 380:\t\tif (fdf-\u003efd \u003c 0)\n 381:\t\t\treturn fdf-\u003efd;\n 382:\t\tretain_and_null_ptr(lh);\n 383:\t\n 384:\t\thandlereq.fd = fdf-\u003efd;\n 385:\t\tif (copy_to_user(ip, \u0026handlereq, sizeof(handlereq)))\n 386:\t\t\treturn -EFAULT;\n 387:\t\n 388:\t\tfd_publish(fdf);\n 389:\t\n 390:\t\tdev_dbg(\u0026gdev-\u003edev, \"registered chardev handle for %d lines\\n\",\n 391:\t\t\thandlereq.lines);\n 392:\t\n 393:\t\treturn 0;\n 394:\t}\n 395:\t#endif /* CONFIG_GPIO_CDEV_V1 */\n 396:\t\n 397:\t/**\n 398:\t * struct line - contains the state of a requested line\n 399:\t * @desc: the GPIO descriptor for this line.\n 400:\t * @req: the corresponding line request\n 401:\t * @irq: the interrupt triggered in response to events on this GPIO\n 402:\t * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or\n 403:\t * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied\n 404:\t * @timestamp_ns: cache for the timestamp storing it between hardirq and\n"
}

105/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 15720
							output: 37
							thoughts: 79

Thoughts:

Okay, let's break this down.

**Investigating a Potential Inconsistency in GPIOLIB and IO_URING Interfacing**

Alright, so I'm digging into how these file descriptors are being handled, specifically regarding the communication between the kernel and userspace. My initial thought is focused on `gpiolib-cdev.c`. I see that within the `handlereq`, `ulr`, and `eventreq` functions, the data was *previously* being copied to userspace using `fd_prepare_fd(fdf)`. Now, I'm noticing a shift; they're using `fdf->fd` directly. This makes me curious. Is this a new development, a refactoring, or perhaps an oversight?

My primary concern is this apparent difference in how data is prepared. I need to understand if the change is consistent across the codebase, or if it might be missing elsewhere, potentially introducing a bug or incompatibility.

Now, my attention immediately turns to `io_uring/mock_file.c`. This is where I'd expect to see a similar implementation, if there is one. Specifically, I'm looking at `io_create_mock_file`. I'm hoping it's using the same method to copy file descriptors to user space. It should, at the very least, be consistent with the change in gpiolib. If it isn't, I've got a potential inconsistency that warrants further investigation. This difference may allow a method of exploitation.

106/3

2026/09/19 01:42

tool

read-file

Args:

{
  "File": "io_uring/mock_file.c",
  "FirstLine": 250,
  "LineCount": 35
}

Results:

{
  "Contents": " 250:\t\tmf-\u003esize = mc.file_size;\n 251:\t\tmf-\u003erw_delay_ns = mc.rw_delay_ns;\n 252:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_POLL) {\n 253:\t\t\tfops = \u0026io_mock_poll_fops;\n 254:\t\t\tmf-\u003epollable = true;\n 255:\t\t}\n 256:\t\n 257:\t\tFD_PREPARE(fdf, O_RDWR | O_CLOEXEC,\n 258:\t\t\t   anon_inode_create_getfile(\"[io_uring_mock]\", fops, mf,\n 259:\t\t\t\t\t\t     O_RDWR | O_CLOEXEC, NULL));\n 260:\t\tif (fdf-\u003efd \u003c 0)\n 261:\t\t\treturn fdf-\u003efd;\n 262:\t\n 263:\t\tretain_and_null_ptr(mf);\n 264:\t\tfile = fdf-\u003efile;\n 265:\t\tfile-\u003ef_mode |= FMODE_READ | FMODE_CAN_READ | FMODE_WRITE |\n 266:\t\t\t\tFMODE_CAN_WRITE | FMODE_LSEEK;\n 267:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_SUPPORT_NOWAIT)\n 268:\t\t\tfile-\u003ef_mode |= FMODE_NOWAIT;\n 269:\t\n 270:\t\tmc.out_fd = fdf-\u003efd;\n 271:\t\tif (copy_to_user(uarg, \u0026mc, uarg_size))\n 272:\t\t\treturn -EFAULT;\n 273:\t\n 274:\t\tfd_publish(fdf);\n 275:\t\treturn 0;\n 276:\t}\n 277:\t\n 278:\tstatic int io_probe_mock(struct io_uring_cmd *cmd)\n 279:\t{\n 280:\t\tconst struct io_uring_sqe *sqe = cmd-\u003esqe;\n 281:\t\tstruct io_uring_mock_probe mp, __user *uarg;\n 282:\t\tsize_t uarg_size;\n 283:\t\n 284:\t\tuarg = u64_to_user_ptr(READ_ONCE(sqe-\u003eaddr));\n"
}

107/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 16769
							output: 37
							thoughts: 30

Thoughts:

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

**Debugging a Mock File Creation Function**

Alright, let's dissect this `io_create_mock_file` function. My initial question is about the variable `mc` within it. Line 220 to 250... that's where the critical assignment or usage must be happening. I need to understand what `mc` represents in this context. Is it a file descriptor, a memory chunk, or something else entirely within this mock file implementation? Knowing its type is crucial to understanding the function's overall behavior. I'll need to carefully examine those lines for variable declarations, assignments, and how `mc` is used subsequently. It could be something straightforward, or it could be a pointer to a struct. Let's dig in and see.

108/3

2026/09/19 01:42

tool

read-file

Args:

{
  "File": "io_uring/mock_file.c",
  "FirstLine": 220,
  "LineCount": 35
}

Results:

{
  "Contents": " 220:\t\t * It's a testing only driver that allows exercising edge cases\n 221:\t\t * that wouldn't be possible to hit otherwise.\n 222:\t\t */\n 223:\t\tadd_taint(TAINT_TEST, LOCKDEP_STILL_OK);\n 224:\t\n 225:\t\tuarg = u64_to_user_ptr(READ_ONCE(sqe-\u003eaddr));\n 226:\t\tuarg_size = READ_ONCE(sqe-\u003elen);\n 227:\t\n 228:\t\tif (sqe-\u003eioprio || sqe-\u003e__pad1 || sqe-\u003eaddr3 || sqe-\u003efile_index)\n 229:\t\t\treturn -EINVAL;\n 230:\t\tif (uarg_size != sizeof(mc))\n 231:\t\t\treturn -EINVAL;\n 232:\t\n 233:\t\tmemset(\u0026mc, 0, sizeof(mc));\n 234:\t\tif (copy_from_user(\u0026mc, uarg, uarg_size))\n 235:\t\t\treturn -EFAULT;\n 236:\t\tif (!mem_is_zero(mc.__resv, sizeof(mc.__resv)))\n 237:\t\t\treturn -EINVAL;\n 238:\t\tif (mc.flags \u0026 ~IO_VALID_CREATE_FLAGS)\n 239:\t\t\treturn -EINVAL;\n 240:\t\tif (mc.file_size \u003e SZ_1G)\n 241:\t\t\treturn -EINVAL;\n 242:\t\tif (mc.rw_delay_ns \u003e NSEC_PER_SEC)\n 243:\t\t\treturn -EINVAL;\n 244:\t\n 245:\t\tmf = kzalloc_obj(*mf, GFP_KERNEL_ACCOUNT);\n 246:\t\tif (!mf)\n 247:\t\t\treturn -ENOMEM;\n 248:\t\n 249:\t\tinit_waitqueue_head(\u0026mf-\u003epoll_wq);\n 250:\t\tmf-\u003esize = mc.file_size;\n 251:\t\tmf-\u003erw_delay_ns = mc.rw_delay_ns;\n 252:\t\tif (mc.flags \u0026 IORING_MOCK_CREATE_F_POLL) {\n 253:\t\t\tfops = \u0026io_mock_poll_fops;\n 254:\t\t\tmf-\u003epollable = true;\n"
}

109/3

2026/09/19 01:42

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 17625
							output: 40
							thoughts: 1537

Thoughts:

**Analyzing File Descriptor Management and Potential Uninitialized Memory Issues**

Okay, let's break this down systematically. I'm focusing on these changes around file descriptor handling, specifically looking for any potential vulnerabilities related to uninitialized memory. I've got to ensure the file descriptor and file pointer are always handled correctly, with proper cleanup in case of errors.

First, I see that `mc` is initialized, copied from user space, and then `mc.out_fd` is set and copied back to user space. This is the starting point to understand the changes in `include/linux/file.h`. I've gone through `include/linux/file.h`, focusing on the core changes. The most important parts seem to be the `FD_PREPARE` macro and the related `__fd_prepare`, `__fd_prepare_cleanup`, and `fd_publish` functions.

The key is in understanding how `FD_PREPARE` works: it sets up a `struct fd_prepare` guard (`_guard`) that manages the lifecycle of a file descriptor and file pointer. It uses a statement expression to initialize the `fd` and `file` fields. The critical part is how errors are handled. If `get_unused_fd_flags` or `_file_owned` fail, the code gracefully handles the error, calls `put_unused_fd` on the fd or already returns an error, before the cleanup occurs. After error handling, `__fd_prepare` returns with `fd = -ENOMEM` (for instance) and `file = NULL`. It guarantees that the guard structure is always properly initialized, even in case of an error. `fd_publish` installs the file descriptor into the file descriptor table. The cleanup function is called when the guard goes out of scope and the file descriptor gets cleaned up, even in case of an error.

I've carefully considered what happens when the guard is out of scope and `__fd_prepare_cleanup` is called. If the operation fails before `fd_publish` is called (which means `fdf->fd` is negative, which is checked by `VFS_WARN_ON_ONCE` in `fd_publish`), the cleanup function will properly release the allocated file descriptor and the file pointer. If, however, the process continues and `fd_publish` is called, `take_fd` gets the file descriptor which is a valid file descriptor; the return value of `take_fd` is then returned to the user, and the cleanup is skipped.

I've examined the `struct fd_prepare`. There's no uninitialized memory in this structure. `fd` is an `int` (4 bytes on a 64-bit architecture) and the padding between `fd` and `file` is inconsequential. Importantly, the `struct fd_prepare` guard is only ever allocated on the kernel stack. It is never exposed to user space directly. Thus, there is no direct risk of leaking uninitialized data to userspace through this structure itself. Only the individual members (`fdf->fd` and `fdf->file`) are ever passed.

The `CLASS_INIT` removal in `include/linux/cleanup.h` is just about removing an unused macro, not really relevant.

However, I'm not stopping there. I want to make sure the code *using* `FD_PREPARE` is safe. So, I looked at the call sites within the modified files.

The `spufs_context_open` is fine since it immediately assigns the result of the `FD_PREPARE`.

But the key is the `drivers/gpio/gpiolib-cdev.c` case and the `linehandle_create` function. I see that the `handlereq.fd` field gets assigned the value `fdf->fd` from the `FD_PREPARE` result and copied to user space. I must make sure that `handlereq` is fully initialized *before* this copy occurs. That is my next step.

110/3

2026/09/19 01:43

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 300,
  "LineCount": 40
}

Results:

{
  "Contents": " 300:\t\n 301:\tDEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))\n 302:\t\n 303:\tstatic int linehandle_create(struct gpio_device *gdev, void __user *ip)\n 304:\t{\n 305:\t\tstruct gpiohandle_request handlereq;\n 306:\t\tstruct linehandle_state *lh __free(linehandle_free) = NULL;\n 307:\t\tint i, ret;\n 308:\t\tu32 lflags;\n 309:\t\n 310:\t\tif (copy_from_user(\u0026handlereq, ip, sizeof(handlereq)))\n 311:\t\t\treturn -EFAULT;\n 312:\t\tif ((handlereq.lines == 0) || (handlereq.lines \u003e GPIOHANDLES_MAX))\n 313:\t\t\treturn -EINVAL;\n 314:\t\n 315:\t\tlflags = handlereq.flags;\n 316:\t\n 317:\t\tret = linehandle_validate_flags(lflags);\n 318:\t\tif (ret)\n 319:\t\t\treturn ret;\n 320:\t\n 321:\t\tlh = kzalloc_obj(*lh);\n 322:\t\tif (!lh)\n 323:\t\t\treturn -ENOMEM;\n 324:\t\tlh-\u003egdev = gpio_device_get(gdev);\n 325:\t\n 326:\t\tif (handlereq.consumer_label[0] != '\\0') {\n 327:\t\t\t/* label is only initialized if consumer_label is set */\n 328:\t\t\tlh-\u003elabel = kstrndup(handlereq.consumer_label,\n 329:\t\t\t\t\t     sizeof(handlereq.consumer_label) - 1,\n 330:\t\t\t\t\t     GFP_KERNEL);\n 331:\t\t\tif (!lh-\u003elabel)\n 332:\t\t\t\treturn -ENOMEM;\n 333:\t\t}\n 334:\t\n 335:\t\tlh-\u003enum_descs = handlereq.lines;\n 336:\t\n 337:\t\t/* Request each GPIO */\n 338:\t\tfor (i = 0; i \u003c handlereq.lines; i++) {\n 339:\t\t\tu32 offset = handlereq.lineoffsets[i];\n"
}

111/3

2026/09/19 01:43

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 20693
							output: 41
							thoughts: 93

Thoughts:

**My Analysis of the Line Handle Creation Process**

Okay, so I'm looking at `linehandle_create` and the way the request is handled. The core of it seems to be this: `handlereq` is initially copied from user space using `copy_from_user`. My immediate concern, as always, is whether uninitialized memory could be a problem here. But, they've explicitly addressed this. The code then sets `handlereq.fd` to `fdf->fd` and then copies the potentially modified `handlereq` *back* to user space. Since all the fields of `handlereq` are, in fact, copied from user space initially, I'm satisfied that there shouldn't be any uninitialized byte issues lurking around.

That said, I'm not going to stop there. I need to take a look at `linereq_create` and `lineevent_create` as well to make sure there aren't similar vulnerabilities in those. It's good to be thorough.

112/3

2026/09/19 01:43

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 1650,
  "LineCount": 40
}

Results:

{
  "Contents": "1650:\t\tINIT_KFIFO(lr-\u003eevents);\n1651:\t\tlr-\u003eevent_buffer_size = ulr.event_buffer_size;\n1652:\t\tif (lr-\u003eevent_buffer_size == 0)\n1653:\t\t\tlr-\u003eevent_buffer_size = ulr.num_lines * 16;\n1654:\t\telse if (lr-\u003eevent_buffer_size \u003e GPIO_V2_LINES_MAX * 16)\n1655:\t\t\tlr-\u003eevent_buffer_size = GPIO_V2_LINES_MAX * 16;\n1656:\t\n1657:\t\tatomic_set(\u0026lr-\u003eseqno, 0);\n1658:\t\n1659:\t\t/* Request each GPIO */\n1660:\t\tfor (i = 0; i \u003c ulr.num_lines; i++) {\n1661:\t\t\tu32 offset = ulr.offsets[i];\n1662:\t\t\tstruct gpio_desc *desc = gpio_device_get_desc(gdev, offset);\n1663:\t\n1664:\t\t\tif (IS_ERR(desc))\n1665:\t\t\t\treturn PTR_ERR(desc);\n1666:\t\n1667:\t\t\tret = gpiod_request_user(desc, lr-\u003elabel);\n1668:\t\t\tif (ret)\n1669:\t\t\t\treturn ret;\n1670:\t\n1671:\t\t\tlr-\u003elines[i].desc = desc;\n1672:\t\t\tflags = gpio_v2_line_config_flags(lc, i);\n1673:\t\t\tgpio_v2_line_config_flags_to_desc_flags(flags, \u0026desc-\u003eflags);\n1674:\t\n1675:\t\t\tret = gpiod_set_transitory(desc, false);\n1676:\t\t\tif (ret \u003c 0)\n1677:\t\t\t\treturn ret;\n1678:\t\n1679:\t\t\tedflags = flags \u0026 GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;\n1680:\t\t\t/*\n1681:\t\t\t * Lines have to be requested explicitly for input\n1682:\t\t\t * or output, else the line will be treated \"as is\".\n1683:\t\t\t */\n1684:\t\t\tif (flags \u0026 GPIO_V2_LINE_FLAG_OUTPUT) {\n1685:\t\t\t\tint val = gpio_v2_line_config_output_value(lc, i);\n1686:\t\n1687:\t\t\t\tret = gpiod_direction_output_nonotify(desc, val);\n1688:\t\t\t\tif (ret)\n1689:\t\t\t\t\treturn ret;\n"
}

113/3

2026/09/19 01:43

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 21730
							output: 41
							thoughts: 12

Thoughts:

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

**Decoding the Data Source: Pinpointing the `url` Origin**

Alright, so the task at hand is to trace the lineage of `url`. Essentially, I need to figure out the exact point in the code (or data flow, depending on context) where this `url` variable, or data element, was introduced, instantiated, or defined. My initial thought process involves a methodical approach – perhaps a quick search, or maybe a more refined analysis of the surrounding code/data.

I am essentially trying to understand the provenance of `url`. Did it come from a configuration file, an external API call, user input, a database lookup, or a hard-coded value within some method? The answer dictates so many downstream implications, I need to understand its root. I'll need to go beyond surface level searching in many cases, and work backwards through its history. This first pass is about locating that initial read, the source.

114/3

2026/09/19 01:43

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 1620,
  "LineCount": 35
}

Results:

{
  "Contents": "1620:\t\t\treturn -EINVAL;\n1621:\t\n1622:\t\tlc = \u0026ulr.config;\n1623:\t\tret = gpio_v2_line_config_validate(lc, ulr.num_lines);\n1624:\t\tif (ret)\n1625:\t\t\treturn ret;\n1626:\t\n1627:\t\tlr = kvzalloc_flex(*lr, lines, ulr.num_lines);\n1628:\t\tif (!lr)\n1629:\t\t\treturn -ENOMEM;\n1630:\t\tlr-\u003enum_lines = ulr.num_lines;\n1631:\t\n1632:\t\tlr-\u003egdev = gpio_device_get(gdev);\n1633:\t\n1634:\t\tfor (i = 0; i \u003c ulr.num_lines; i++) {\n1635:\t\t\tlr-\u003elines[i].req = lr;\n1636:\t\t\tWRITE_ONCE(lr-\u003elines[i].sw_debounced, 0);\n1637:\t\t\tINIT_DELAYED_WORK(\u0026lr-\u003elines[i].work, debounce_work_func);\n1638:\t\t}\n1639:\t\n1640:\t\tif (ulr.consumer[0] != '\\0') {\n1641:\t\t\t/* label is only initialized if consumer is set */\n1642:\t\t\tlr-\u003elabel = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,\n1643:\t\t\t\t\t     GFP_KERNEL);\n1644:\t\t\tif (!lr-\u003elabel)\n1645:\t\t\t\treturn -ENOMEM;\n1646:\t\t}\n1647:\t\n1648:\t\tmutex_init(\u0026lr-\u003econfig_mutex);\n1649:\t\tinit_waitqueue_head(\u0026lr-\u003ewait);\n1650:\t\tINIT_KFIFO(lr-\u003eevents);\n1651:\t\tlr-\u003eevent_buffer_size = ulr.event_buffer_size;\n1652:\t\tif (lr-\u003eevent_buffer_size == 0)\n1653:\t\t\tlr-\u003eevent_buffer_size = ulr.num_lines * 16;\n1654:\t\telse if (lr-\u003eevent_buffer_size \u003e GPIO_V2_LINES_MAX * 16)\n"
}

115/3

2026/09/19 01:43

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 22597
							output: 41
							thoughts: 13

Thoughts:

Okay, I'm ready. Here's a summary in the first person, assuming I'm the expert you describe, and starting with the bolded header:

**Diving Deep into the Data: Lines 1600-1620**

Alright, let's see what we're dealing with here, specifically focusing on lines 1600-1620. Given the context of this work, I'm immediately looking for key indicators – the specific parameters and their interactions are where the interesting stuff usually resides. I need to understand what's being measured, what the baseline is, and where the deviation lies. Are we talking about a sudden spike, a gradual trend, or something cyclical? This will influence my interpretation.

My initial thought is to cross-reference this segment with the broader dataset and the model’s overall behavior. Is this an isolated anomaly or a part of a larger, potentially significant pattern? I need to ascertain the impact, what other variables may be correlated, and start asking "why?" Why is this happening now? What's the causal link?

Furthermore, I am also checking the assumptions that are underlying the section. Are those reasonable? If not, the whole section may need some heavy scrutiny and possible re-modeling. I'm also looking for any obvious flaws in the methodology – data entry errors, mislabeled axes, inappropriate statistical analyses. My years of experience allows me to recognize patterns of concern, and I can quickly start to isolate the most likely explanations. This is where the magic happens – the quick mental correlations and cross-references that come from years of doing this kind of work.

Finally, I'm checking to see if these lines have already been analyzed in the past. If the information is new, it will require deep dives to understand the parameters. If the information has been previously discussed, then it will require a re-evaluation to determine if there are any new ideas that should be explored.

116/3

2026/09/19 01:43

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 1600,
  "LineCount": 25
}

Results:

{
  "Contents": "1600:\t};\n1601:\t\n1602:\tDEFINE_FREE(linereq_free, struct linereq *, if (!IS_ERR_OR_NULL(_T)) linereq_free(_T))\n1603:\t\n1604:\tstatic int linereq_create(struct gpio_device *gdev, void __user *ip)\n1605:\t{\n1606:\t\tstruct gpio_v2_line_request ulr;\n1607:\t\tstruct gpio_v2_line_config *lc;\n1608:\t\tstruct linereq *lr __free(linereq_free) = NULL;\n1609:\t\tu64 flags, edflags;\n1610:\t\tunsigned int i;\n1611:\t\tint ret;\n1612:\t\n1613:\t\tif (copy_from_user(\u0026ulr, ip, sizeof(ulr)))\n1614:\t\t\treturn -EFAULT;\n1615:\t\n1616:\t\tif ((ulr.num_lines == 0) || (ulr.num_lines \u003e GPIO_V2_LINES_MAX))\n1617:\t\t\treturn -EINVAL;\n1618:\t\n1619:\t\tif (!mem_is_zero(ulr.padding, sizeof(ulr.padding)))\n1620:\t\t\treturn -EINVAL;\n1621:\t\n1622:\t\tlc = \u0026ulr.config;\n1623:\t\tret = gpio_v2_line_config_validate(lc, ulr.num_lines);\n1624:\t\tif (ret)\n"
}

117/3

2026/09/19 01:43

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 23479
							output: 41
							thoughts: 21

Thoughts:

**My Immediate Observations**

Okay, so I'm looking at this code and immediately see a pattern. It looks like both `ulr` and `lineevent_create` are being copied from user space. That jumps out at me because it suggests potential security vulnerabilities or inefficiencies, depending on the context. I need to dig deeper to understand *why* this is happening and what implications it has. Is this a deliberate design choice, or a potential bug? And more importantly, what are the implications for performance and security? I need more information to form a solid conclusion, but this is definitely something to flag and investigate.

118/3

2026/09/19 01:43

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 2040,
  "LineCount": 30
}

Results:

{
  "Contents": "2040:\t\t/* Only one bias flag can be set. */\n2041:\t\tif (((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_DISABLE) \u0026\u0026\n2042:\t\t     (lflags \u0026 (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |\n2043:\t\t\t\tGPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||\n2044:\t\t    ((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) \u0026\u0026\n2045:\t\t     (lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_UP)))\n2046:\t\t\treturn -EINVAL;\n2047:\t\n2048:\t\tle = kzalloc_obj(*le);\n2049:\t\tif (!le)\n2050:\t\t\treturn -ENOMEM;\n2051:\t\tle-\u003egdev = gpio_device_get(gdev);\n2052:\t\n2053:\t\tif (eventreq.consumer_label[0] != '\\0') {\n2054:\t\t\t/* label is only initialized if consumer_label is set */\n2055:\t\t\tle-\u003elabel = kstrndup(eventreq.consumer_label,\n2056:\t\t\t\t\t     sizeof(eventreq.consumer_label) - 1,\n2057:\t\t\t\t\t     GFP_KERNEL);\n2058:\t\t\tif (!le-\u003elabel)\n2059:\t\t\t\treturn -ENOMEM;\n2060:\t\t}\n2061:\t\n2062:\t\tret = gpiod_request_user(desc, le-\u003elabel);\n2063:\t\tif (ret)\n2064:\t\t\treturn ret;\n2065:\t\tle-\u003edesc = desc;\n2066:\t\tle-\u003eeflags = eflags;\n2067:\t\n2068:\t\tlinehandle_flags_to_desc_flags(lflags, \u0026desc-\u003eflags);\n2069:\t\n"
}

119/3

2026/09/19 01:43

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 24169
							output: 41
							thoughts: 10

Thoughts:

Okay, here's the summary, rendered as a first-person account, focusing on the core ideas and assuming a level of expertise:

**My Initial Assessment of `lineevent_create`**

Alright, let's dive into this `lineevent_create` function. My initial thought is to immediately consider the context of its use. What kind of line events are we talking about? Network data packets, user inputs, signals, etc.? Understanding that is fundamental. I'm going to quickly look for any clues about the underlying data structure it operates on. Are we dealing with structs, classes, or something more basic? The function's signature will be key.

I need to understand its role. Is it a factory, allocating memory and populating a new `lineevent` structure? Or is it more of a configuration and initialization function? Knowing whether it's responsible for memory management is critical, as that dictates my primary concerns regarding potential memory leaks, buffer overflows, or improper resource handling. I'll need to scrutinize how it handles error conditions and what mechanisms are in place for error propagation. Are exceptions being thrown, error codes returned, or is it relying on a global error state? I need to know how resilient it is.

The logic flow within the function itself will be paramount. I'm going to quickly map out the typical execution path - what data is required, the steps for initializing the event, any conditional branches, and the final return statement. Are there any resource dependencies – mutexes, semaphores, or other shared resources? These need careful consideration as they are potential points of deadlock or race conditions. I'll be looking for efficient use of any library functions, the handling of data types and casts.

Ultimately, I'm expecting this function to be a relatively self-contained unit of functionality, responsible for creating and/or initializing an event representation of some kind of a data stream or stream-related action on a given line. My primary objective is a thorough understanding of its operational details.

120/3

2026/09/19 01:44

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 2020,
  "LineCount": 25
}

Results:

{
  "Contents": "2020:\t\n2021:\t\toffset = eventreq.lineoffset;\n2022:\t\tlflags = eventreq.handleflags;\n2023:\t\teflags = eventreq.eventflags;\n2024:\t\n2025:\t\tdesc = gpio_device_get_desc(gdev, offset);\n2026:\t\tif (IS_ERR(desc))\n2027:\t\t\treturn PTR_ERR(desc);\n2028:\t\n2029:\t\t/* Return an error if a unknown flag is set */\n2030:\t\tif ((lflags \u0026 ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||\n2031:\t\t    (eflags \u0026 ~GPIOEVENT_REQUEST_VALID_FLAGS))\n2032:\t\t\treturn -EINVAL;\n2033:\t\n2034:\t\t/* This is just wrong: we don't look for events on output lines */\n2035:\t\tif ((lflags \u0026 GPIOHANDLE_REQUEST_OUTPUT) ||\n2036:\t\t    (lflags \u0026 GPIOHANDLE_REQUEST_OPEN_DRAIN) ||\n2037:\t\t    (lflags \u0026 GPIOHANDLE_REQUEST_OPEN_SOURCE))\n2038:\t\t\treturn -EINVAL;\n2039:\t\n2040:\t\t/* Only one bias flag can be set. */\n2041:\t\tif (((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_DISABLE) \u0026\u0026\n2042:\t\t     (lflags \u0026 (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |\n2043:\t\t\t\tGPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||\n2044:\t\t    ((lflags \u0026 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) \u0026\u0026\n"
}

121/3

2026/09/19 01:44

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 25089
							output: 41
							thoughts: 12

Thoughts:

Okay, I'm ready. Here's a summary, in the first person, assuming I'm an expert in the field and considering the prompt's instruction to summarize "before line 2020":

**My Initial Assessment and Pre-2020 Considerations**

Alright, before I dive too deep into anything, I need to get my bearings and establish a baseline. Considering the "before line 2020" constraint, I should be focused on the earlier trends, developments, and common assumptions in this domain. What were the prevailing paradigms at that time? What critical breakthroughs had been made or were anticipated? Any ongoing debates or controversies that would have shaped the landscape leading up to that point?

I'll be looking for key indicators of that era: the technologies in their infancy, the major players making their moves, and the theoretical underpinnings that were being actively explored. Were there any dominant research programs or industrial initiatives that were setting the agenda? And if so, what were their core tenets and predicted outcomes? Essentially, my focus is understanding the context, so I can see what came *before* and start making intelligent inferences about possible developments later on. My initial assessment hinges on building this foundation of understanding.

122/3

2026/09/19 01:45

tool

read-file

Args:

{
  "File": "drivers/gpio/gpiolib-cdev.c",
  "FirstLine": 2005,
  "LineCount": 20
}

Results:

{
  "Contents": "2005:\t\n2006:\tstatic int lineevent_create(struct gpio_device *gdev, void __user *ip)\n2007:\t{\n2008:\t\tstruct gpioevent_request eventreq;\n2009:\t\tstruct lineevent_state *le __free(lineevent_free) = NULL;\n2010:\t\tstruct gpio_desc *desc;\n2011:\t\tu32 offset;\n2012:\t\tu32 lflags;\n2013:\t\tu32 eflags;\n2014:\t\tint ret;\n2015:\t\tint irq, irqflags = 0;\n2016:\t\tchar *label;\n2017:\t\n2018:\t\tif (copy_from_user(\u0026eventreq, ip, sizeof(eventreq)))\n2019:\t\t\treturn -EFAULT;\n2020:\t\n2021:\t\toffset = eventreq.lineoffset;\n2022:\t\tlflags = eventreq.handleflags;\n2023:\t\teflags = eventreq.eventflags;\n2024:\t\n"
}

123/3

2026/09/19 01:45

llm

kmsan-evaluator

Model:

gemini-3.8-flash

Args:

null

Results:

null

Tokens:

							input: 25690
							output: 393
							thoughts: 2089

Thoughts:

**Analysis of File Descriptor Preparation Refactoring**

Alright, let's break this down. It seems we've got a patch that's refactoring the `fd_prepare` abstraction, a crucial component for managing file descriptors and their associated resources across the kernel. My initial impression is that this is a *simplification* of the existing RAII (Resource Acquisition Is Initialization) cleanup mechanism. The intent is to make the code cleaner and more direct, replacing the older `err`, `__fd`, `__file` approach with a more concise `fd` and `file` structure. This should improve readability, which is always a plus.

I've gone through the code changes. The original implementation used macros and had an `err` field. The new approach uses direct field access (`fdf->fd`, `fdf->file`) and error checking is now direct, via `fdf->fd < 0`. This is a welcome change. The cleanup strategy, handled by `__fd_prepare_cleanup`, looks sound; it uses the `fd` and `file` from the `fd_prepare` structure to properly release the file descriptor and the associated file.

Now, the question becomes: does this refactoring introduce *uninitialized memory risks*? That's the critical concern, and I've carefully assessed this.

I've checked the standard KMSAN criteria:

1. **Kernel Data to Userspace:** I can see that file descriptors (`fdf->fd`) are being passed to userspace via `put_user` and also in a couple of ioctl structures which I checked closely, such as `gpiolib-cdev.c` and others. But `fdf->fd` is *always* initialized by `__fd_prepare`. The fields being copied to user space are either integral `int` descriptors or fully initialized structures. No new fields or paddings are exposed. Therefore, no KMSAN risk here.

2. **Conditional Logic:** The core check is `fdf->fd < 0`, and the code *explicitly* initializes `fdf->fd`. It's a straightforward check on an initialized variable. No risk of using uninitialized variables in any decision-making path.

3. **Complex Data Structures:** We aren't creating complex data structures with potentially uninitialized fields that could be read later.

4. **Bounds/Length Checks:** This is a non-issue.

I've thoroughly reviewed the `__fd_prepare_cleanup` function, which handles releasing the resources. The cleanup code is carefully constructed; it checks `fdf->fd >= 0` to make sure we're only attempting to release valid file descriptors and that `_guard` is always initialized by `__fd_prepare`. The potential error paths where either file descriptor acquisition or file creation fails do not leave any uninitialized data anywhere.

So, *no* uninitialized reads occur anywhere in the code. I've also thought about potential edge cases.

The bugs this patch is *likely* to introduce relate to reference counting (double `fput` or leaked `fput` calls), descriptor table issues, or potential use-after-free conditions. Those are *not* KMSAN issues; those are the domain of KASAN (Kernel Address Sanitizer), refcount debugging tools, and standard kernel warnings, and I'm confident that KASAN will catch any issues.

I've concluded that this patch does *not* introduce or expose any uninitialized memory risks. Dedicated KMSAN fuzzing is not necessary here. Standard KASAN will be sufficient. I'm ready to approve the patch. Let's make sure the reasoning is clear:

* The patch *simplifies* and refactors the `fd_prepare` abstraction.
* The structures are fully initialized during preparation.
* Any values exposed to user space are either initialized integers or initialized structures.
* This is not a KMSAN problem, but KASAN is the right tool here.

I've re-checked everything; the analysis is complete.

124/3

2026/09/19 01:46

tool

set-results

Args:

{
  "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

Results:

{
  "KMSANReasoning": "The patch refactors the `fd_prepare` RAII cleanup class and its callers across several kernel subsystems (fs, net, bpf, gpio, media, drm). Specifically, it replaces `struct fd_prepare`'s internal fields (`err`, `__fd`, `__file`) with `fd` and `file`, checks `fdf-\u003efd \u003c 0` instead of `fdf.err`, and accesses `fdf-\u003efd` and `fdf-\u003efile` directly via a pointer instead of through accessor macros.\n\nKMSAN vs. KASAN applicability:\n- KMSAN detects reads of uninitialized stack, heap, or page memory, and information leaks to user space. In this patch, the `fd_prepare` guard is always fully initialized with a compound literal in `__fd_prepare()` (`{ .fd = fd, .file = file }`). All places copying an fd to user space (`put_user` in `scm_recv_one_fd`/`receive_fd`, or `copy_to_user` in `gpiolib-cdev`, `kcm_ioctl`, and `io_uring`) operate on fully initialized integers or previously zeroed/copied structures. No uninitialized memory or structure padding is exposed to user space or used in branching.\n- KASAN and standard kernel debug facilities (such as refcount checking and lockdep) are well-suited to catch the types of risks introduced by RAII file/fd lifecycle changes, such as use-after-free, double fput/put_unused_fd, or leaking descriptor table references.\n\nBecause no uninitialized memory usage or kernel-to-user info-leak risks are created, a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}