syzbot


KCSAN: data-race in dentry_unlink_inode / path_openat (3)

Status: moderation: reported on 2026/05/08 01:59
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+fdbe96d95ed5185a602f@syzkaller.appspotmail.com
First crash: 4d07h, last: 4d07h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
98cf4d46-aa06-433f-8c59-cec3df49d636 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in dentry_unlink_inode / path_openat (3) 2026/05/08 01:59 2026/05/08 01:59 2026/05/08 02:20 06a6ee865c1ddbbe04beddc5a2bf68cc0e8aa03c
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in dentry_unlink_inode / path_openat (2) fs 6 2 79d 83d 0/29 auto-obsoleted due to no activity on 2026/04/19 00:21
upstream KCSAN: data-race in dentry_unlink_inode / path_openat fs 6 1 144d 144d 0/29 auto-obsoleted due to no activity on 2026/02/13 00:48

Sample crash report:
==================================================================
BUG: KCSAN: data-race in dentry_unlink_inode / path_openat

write to 0xffff8881005e1e70 of 8 bytes by task 6072 on cpu 0:
 __d_clear_type_and_inode fs/dcache.c:420 [inline]
 dentry_unlink_inode+0x6a/0x290 fs/dcache.c:457
 __dentry_kill+0x145/0x4d0 fs/dcache.c:718
 finish_dput+0x2b/0x200 fs/dcache.c:927
 dput+0x52/0x60 fs/dcache.c:976
 end_renaming fs/namei.c:4124 [inline]
 filename_renameat2+0x493/0x6e0 fs/namei.c:6174
 __do_sys_rename fs/namei.c:6216 [inline]
 __se_sys_rename+0x4a/0x1c0 fs/namei.c:6212
 __x64_sys_rename+0x31/0x40 fs/namei.c:6212
 x64_sys_call+0x2b3/0x3020 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881005e1e70 of 8 bytes by task 6039 on cpu 1:
 step_into fs/namei.c:2137 [inline]
 open_last_lookups fs/namei.c:4646 [inline]
 path_openat+0x65f/0x2050 fs/namei.c:4855
 do_file_open+0x16c/0x290 fs/namei.c:4887
 do_sys_openat2+0x94/0x130 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1381
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88811b9e20b8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6039 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/08 01:58 upstream fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / path_openat
* Struck through repros no longer work on HEAD.