syzbot


KCSAN: data-race in dentry_unlink_inode / step_into_slowpath

Status: moderation: reported on 2025/12/02 06:25
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+6b0be41ebcb0c7cd64a5@syzkaller.appspotmail.com
First crash: 149d, last: 12h18m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
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 0xffff88811a4eae70 of 8 bytes by task 11918 on cpu 0:
 __d_clear_type_and_inode fs/dcache.c:420 [inline]
 dentry_unlink_inode+0x6a/0x290 fs/dcache.c:457
 d_delete+0xc8/0xe0 fs/dcache.c:2597
 d_delete_notify+0x32/0x100 include/linux/fsnotify.h:375
 vfs_unlink+0x289/0x490 fs/namei.c:5513
 filename_unlinkat+0x1e2/0x410 fs/namei.c:5568
 __do_sys_unlink fs/namei.c:5603 [inline]
 __se_sys_unlink+0x2b/0xe0 fs/namei.c:5600
 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5600
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811a4eae70 of 8 bytes by task 2988 on cpu 1:
 step_into_slowpath+0x12c/0x4c0 fs/namei.c:2103
 step_into fs/namei.c:2148 [inline]
 walk_component fs/namei.c:2284 [inline]
 lookup_last fs/namei.c:2785 [inline]
 path_lookupat+0x330/0x500 fs/namei.c:2809
 filename_lookup+0x190/0x390 fs/namei.c:2838
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888130d15098 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2988 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (291):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/29 22:10 upstream 57b8e2d666a3 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/29 17:21 upstream 57b8e2d666a3 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/29 12:00 upstream dca922e019dd 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/28 20:55 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/28 19:29 upstream dca922e019dd ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/28 08:16 upstream 3b3bea6d4b9c ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/28 00:26 upstream 3b3bea6d4b9c ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/27 21:08 upstream 254f49634ee1 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/27 14:52 upstream 254f49634ee1 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/26 20:13 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/25 18:35 upstream 897d54018cc9 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/25 03:36 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/24 14:45 upstream dd6c438c3e64 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/24 01:06 upstream 45dcf5e28813 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/23 15:44 upstream 2e6803928193 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/23 01:42 upstream 2a4c0c11c019 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/22 12:00 upstream 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/22 07:39 upstream 6596a02b2078 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/22 01:45 upstream 4ee64205ffaa 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/21 17:11 upstream b4e07588e743 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/21 04:50 upstream b4e07588e743 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/20 21:43 upstream a5d1079c28a5 e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/20 14:04 upstream c1f49dea2b8f e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/19 23:28 upstream c1f49dea2b8f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/19 15:20 upstream faeab166167f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/18 21:17 upstream eb5249b12507 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/18 06:57 upstream 8541d8f725c6 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/17 14:14 upstream 43cfbdda5af6 de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/17 01:03 upstream 3cd8b194bf34 de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/16 12:40 upstream 1d51b370a0f8 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/16 02:56 upstream aec2f682d47c df15c5f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/15 12:49 upstream 1f5ffc672165 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/15 01:36 upstream 508fed679541 e2e976a8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/14 14:39 upstream d60bc1401583 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/13 22:26 upstream 26ff969926a0 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/13 12:07 upstream 028ef9c96e96 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/12 23:50 upstream 028ef9c96e96 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/12 10:44 upstream f5459048c38a 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/11 23:38 upstream e753c16cb3dd 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/11 10:46 upstream e774d5f1bc27 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/10 19:48 upstream 7c6c4ed80b87 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dentry_unlink_inode / step_into_slowpath
2026/04/10 06:43 upstream 9a9c8ce300cd 38c8e246 .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.