syzbot


KCSAN: data-race in set_nlink / set_nlink

Status: moderation: reported on 2023/12/08 00:02
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+1b6aa3108f79850c5fa6@syzkaller.appspotmail.com
First crash: 952d, last: 1d05h

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

read to 0xffff88810750ceb8 of 4 bytes by task 3703 on cpu 1:
 set_nlink+0x29/0xb0 fs/inode.c:-1
 kernfs_refresh_inode fs/kernfs/inode.c:182 [inline]
 kernfs_iop_permission+0x1e2/0x220 fs/kernfs/inode.c:290
 do_inode_permission fs/namei.c:526 [inline]
 inode_permission+0x1c7/0x310 fs/namei.c:593
 may_lookup fs/namei.c:1836 [inline]
 link_path_walk+0x162/0x900 fs/namei.c:2445
 path_openat+0x1de/0x2170 fs/namei.c:4042
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88810750ceb8 of 4 bytes by task 2991 on cpu 0:
 set_nlink+0x99/0xb0 fs/inode.c:458
 kernfs_refresh_inode fs/kernfs/inode.c:182 [inline]
 kernfs_iop_permission+0x1e2/0x220 fs/kernfs/inode.c:290
 do_inode_permission fs/namei.c:526 [inline]
 inode_permission+0x1c7/0x310 fs/namei.c:593
 may_lookup fs/namei.c:1836 [inline]
 link_path_walk+0x162/0x900 fs/namei.c:2445
 path_lookupat+0x63/0x2a0 fs/namei.c:2653
 filename_lookup+0x147/0x340 fs/namei.c:2683
 vfs_statx+0x9d/0x390 fs/stat.c:353
 vfs_fstatat+0x115/0x170 fs/stat.c:375
 __do_sys_newfstatat fs/stat.c:542 [inline]
 __se_sys_newfstatat+0x55/0x260 fs/stat.c:536
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:536
 x64_sys_call+0x135a/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000008 -> 0x00000009

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2991 Comm: udevd Not tainted 6.16.0-syzkaller-06699-ge8d780dcd957 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (780):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/31 03:30 upstream e8d780dcd957 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/30 18:30 upstream 4b290aae788e f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/29 07:44 upstream ae388edd4a8f c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/28 17:49 upstream 038d61fd6422 6654ea9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/27 09:56 upstream ec2df4364666 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/27 04:46 upstream 302f88ff3584 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/26 08:00 upstream 5f33ebd2018c fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/25 15:04 upstream 2942242dde89 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/24 13:14 upstream 25fae0b93d1d 65d60d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/23 07:36 upstream 89be9a83ccf1 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/23 03:19 upstream 89be9a83ccf1 8e9d1dc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/21 12:15 upstream 89be9a83ccf1 56d87229 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/20 02:45 upstream bf61759db409 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/15 08:51 upstream 155a3c003e55 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/14 18:28 upstream 347e9f5043c8 d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/12 23:00 upstream 3f31a806a62e 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/12 09:12 upstream 379f604cc3dc 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/12 07:10 upstream 40f92e79b0aa 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/10 03:56 upstream 8c2e52ebbe88 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/10 00:25 upstream 8c2e52ebbe88 f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/09 13:34 upstream 733923397fd9 f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/07 14:41 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/06 15:21 upstream 1f988d0788f5 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/05 22:34 upstream 05df91921da6 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/05 18:51 upstream a79a588fc176 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/03 20:01 upstream 17bbde2e1716 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/03 06:41 upstream b4911fb0b060 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/03 01:55 upstream b4911fb0b060 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/07/01 21:06 upstream 66701750d556 091a06cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/30 13:37 upstream d0b3b7b22dfa fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/28 07:24 upstream 67a993863163 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/27 07:51 upstream f02769e7f272 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/26 08:47 upstream ee88bddf7f2f 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/25 03:53 upstream 7595b66ae9de 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/24 05:55 upstream 78f4e737a53e e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/23 16:16 upstream 86731a2a651e d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/22 19:13 upstream 739a6c93cc75 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/21 15:46 upstream 3f75bfff44be d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/20 14:08 upstream 75f5f23f8787 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/19 21:08 upstream 24770983ccfe ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/19 04:18 upstream fb4d33ab452e ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/17 13:31 upstream 9afe652958c3 cfebc887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/16 09:44 upstream 08215f5486ec 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/15 08:00 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/14 15:11 upstream 4774cfe3543a 0e8da31f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/14 10:55 upstream 02adc1490e6d 0e8da31f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/13 02:19 upstream 27605c8c0f69 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/11 11:00 upstream aef17cb3d3c4 5d7e17ca .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/09 20:47 upstream 19272b37aa4f 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/09 00:29 upstream 939f15e640f1 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2025/06/08 00:57 upstream 5b032cac6225 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2023/12/08 00:00 upstream 9ace34a8e446 28b24332 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
2023/11/23 10:29 upstream 9b6de136b5f0 fc59b78e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in set_nlink / set_nlink
* Struck through repros no longer work on HEAD.