syzbot


KCSAN: data-race in dentry_unlink_inode / step_into_slowpath

Status: moderation: reported on 2025/12/02 06:25
Subsystems: fs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+6b0be41ebcb0c7cd64a5@syzkaller.appspotmail.com
First crash: 201d, last: 22h26m
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
6587229b-958e-4aa2-934a-192d1c037f30 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in dentry_unlink_inode / step_into_slowpath 2026/05/24 10:56 2026/05/24 10:56 2026/05/24 11:27 c69befb30ac10e158cc9d1557b508ee3f0eca1de

			
		
1fd06afa-8cfe-4a51-913e-67a9454a818e assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in dentry_unlink_inode / step_into_slowpath 2026/01/15 12:17 2026/01/15 12:17 2026/01/15 12:20 a9d6a79219801d2130df3b1a792c57f0e5428e9f

			
		

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

write to 0xffff888100406f30 of 8 bytes by task 3286 on cpu 0:
 __d_clear_type_and_inode fs/dcache.c:420 [inline]
 dentry_unlink_inode+0x65/0x260 fs/dcache.c:464
 d_delete+0x164/0x180 fs/dcache.c:2695
 d_delete_notify+0x32/0x100 include/linux/fsnotify.h:379
 vfs_unlink+0x287/0x490 fs/namei.c:5526
 filename_unlinkat+0x1dc/0x410 fs/namei.c:5581
 __do_sys_unlink fs/namei.c:5616 [inline]
 __se_sys_unlink+0x2b/0xe0 fs/namei.c:5613
 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5613
 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88
 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 0xffff888100406f30 of 8 bytes by task 2977 on cpu 1:
 step_into_slowpath+0x12c/0x4c0 fs/namei.c:2107
 step_into fs/namei.c:2152 [inline]
 walk_component fs/namei.c:2288 [inline]
 lookup_last fs/namei.c:2789 [inline]
 path_lookupat+0x2eb/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: 0xffff88811af13998 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2977 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 (394):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/20 11:19 upstream 1a3746ccbb0a 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/19 21:35 upstream 5e2e14749c3d 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/19 12:43 upstream 9ecfb2f7287a 570c59ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/19 02:24 upstream 83f1454877cc a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/18 09:58 upstream e771677c937d a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/17 15:03 upstream 66affa37cfac b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/17 13:41 upstream 66affa37cfac 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/16 19:14 upstream b1cbabe84ca1 a3998659 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/16 09:02 upstream a87bbc4578fd 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/16 00:28 upstream 0e0611827f33 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/15 04:56 upstream 95e56f0f293e 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/14 16:49 upstream 8cd9520d35a6 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/14 00:38 upstream 2b07ea76fd28 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/13 12:02 upstream 062871f1371b 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/12 06:43 upstream 2b414a95b8f7 e93da63e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/11 22:47 upstream 2b414a95b8f7 d93a6ab6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/11 15:28 upstream 9716c086c8e8 d93a6ab6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/11 07:09 upstream 9716c086c8e8 b754d2d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/10 13:42 upstream acb7500801e9 f79bac11 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/09 23:27 upstream 2d3090a8aeb5 34dab4be .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/09 17:00 upstream 2d3090a8aeb5 c36c07f6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/08 18:18 upstream 2d3090a8aeb5 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/08 14:42 upstream 4549871118cf 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/07 17:01 upstream 33d8d8ec31b5 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/07 04:12 upstream 979c294509f9 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/06 16:53 upstream 8e65320d91cd cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/06 01:52 upstream c10130c234c8 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/05 11:36 upstream ddd664bbff63 48b6c3fa .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/04 19:58 upstream 9154c4af7829 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/04 06:27 upstream ba3e43a9e601 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/03 02:53 upstream ba3e43a9e601 3c0d2131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/02 16:57 upstream 6f3ed7fec72f 62fe1528 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/02 06:14 upstream 6f3ed7fec72f 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/01 20:49 upstream e43ffb69e043 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/01 14:56 upstream e43ffb69e043 8d8eeb3a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/01 06:04 upstream e43ffb69e043 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/06/01 00:43 upstream 174914ea5513 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/31 09:59 upstream 9d87d0fc8c8e 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/30 16:47 upstream f5e5d3509bff 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/30 00:18 upstream 9215e74f228f 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/29 18:57 upstream 8fde5d1d47f6 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/29 06:18 upstream 8fde5d1d47f6 4624854e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/28 20:57 upstream eb3f4b7426cf 681715f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/28 02:27 upstream eb3f4b7426cf 4c36e7e5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/27 12:08 upstream eb3f4b7426cf 8777bdc3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/05/24 06:24 upstream 4cbfe4502e3d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/03/10 13:40 upstream 1f318b96cc84 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/01/15 00:07 upstream e0d4140e8043 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2025/12/02 06:25 upstream 1d18101a644e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
* Struck through repros no longer work on HEAD.