KCSAN: data-race in __d_instantiate / path

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
d4007c08-f9eb-41c0-af64-e513199170df	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in __d_instantiate / path_lookupat (2)	2026/06/25 00:01	2026/06/25 00:01	2026/06/25 00:38	2e5297c5126f27e51eeef9157f2111c5beb11e4f
04bc1d99-3827-4ddd-8fcb-66df0358bf36	assessment-kcsan	Benign: ✅	❓	KCSAN: data-race in __d_instantiate / path_lookupat (2)	2026/06/23 17:59	2026/06/23 17:59	2026/06/23 18:26	e30e5c89d137d970da183ffdc275130a55fdd832

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __d_instantiate / path_lookupat fs	6				4	123d	192d	0/29	auto-obsoleted due to no activity on 2026/04/18 04:16

Kernel

Title

Rank 🛈

upstream

KCSAN: data-race in __d_instantiate / path_lookupat fs

123d

192d

0/29

auto-obsoleted due to no activity on 2026/04/18 04:16

================================================================== BUG: KCSAN: data-race in __d_instantiate / path_lookupat read-write to 0xffff888100414780 of 4 bytes by task 3289 on cpu 0: fsnotify_update_flags include/linux/fsnotify_backend.h:-1 [inline] __d_instantiate+0x2a8/0x390 fs/dcache.c:2149 d_make_persistent+0x72/0x110 fs/dcache.c:2973 shmem_symlink+0x386/0x3a0 mm/shmem.c:4068 vfs_symlink+0xfd/0x220 fs/namei.c:5656 filename_symlinkat+0xe8/0x2b0 fs/namei.c:5681 __do_sys_symlink fs/namei.c:5708 [inline] __se_sys_symlink+0x42/0x1b0 fs/namei.c:5704 __x64_sys_symlink+0x31/0x40 fs/namei.c:5704 x64_sys_call+0x2465/0x3020 arch/x86/include/generated/asm/syscalls_64.h:89 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff888100414780 of 4 bytes by task 2979 on cpu 1: d_managed include/linux/dcache.h:433 [inline] step_into fs/namei.c:2140 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x19b/0x4c0 fs/namei.c:2813 filename_lookup+0x18f/0x390 fs/namei.c:2842 do_readlinkat+0x74/0x2f0 fs/stat.c:571 __do_sys_readlink fs/stat.c:605 [inline] __se_sys_readlink fs/stat.c:602 [inline] __x64_sys_readlink+0x47/0x60 fs/stat.c:602 x64_sys_call+0x2b51/0x3020 arch/x86/include/generated/asm/syscalls_64.h:90 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000080 -> 0x08300080 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 2979 Comm: udevd Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/06/23 17:59	upstream	502d801f0ab0	4b1d8f01	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __d_instantiate / path_lookupat

Crashes (1):

Assets (help?)