syzbot


KCSAN: data-race in inode_set_ctime_to_ts / inode_set_ctime_to_ts (2)

Status: moderation: reported on 2025/10/26 15:43
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+d7b0ca727977befe2b2d@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in inode_set_ctime_to_ts / inode_set_ctime_to_ts kernfs 6 1 274d 274d 0/29 auto-obsoleted due to no activity on 2025/04/01 13:08

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

write to 0xffff8881071f9888 of 4 bytes by task 3312 on cpu 1:
 inode_set_ctime_to_ts+0x84/0x170 fs/inode.c:2715
 set_inode_attr fs/kernfs/inode.c:165 [inline]
 kernfs_refresh_inode fs/kernfs/inode.c:179 [inline]
 kernfs_iop_permission+0x190/0x220 fs/kernfs/inode.c:290
 do_inode_permission fs/namei.c:526 [inline]
 inode_permission+0x1ca/0x310 fs/namei.c:593
 may_create+0x196/0x1f0 fs/namei.c:3318
 vfs_mkdir+0x5a/0x340 fs/namei.c:4436
 do_mkdirat+0x132/0x3f0 fs/namei.c:4486
 __do_sys_mkdirat fs/namei.c:4503 [inline]
 __se_sys_mkdirat fs/namei.c:4501 [inline]
 __x64_sys_mkdirat+0x4c/0x60 fs/namei.c:4501
 x64_sys_call+0x2b7/0x3000 arch/x86/include/generated/asm/syscalls_64.h:259
 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 0xffff8881071f9888 of 4 bytes by task 3315 on cpu 0:
 inode_set_ctime_to_ts+0x84/0x170 fs/inode.c:2715
 set_inode_attr fs/kernfs/inode.c:165 [inline]
 kernfs_refresh_inode fs/kernfs/inode.c:179 [inline]
 kernfs_iop_permission+0x190/0x220 fs/kernfs/inode.c:290
 do_inode_permission fs/namei.c:526 [inline]
 inode_permission+0x1ca/0x310 fs/namei.c:593
 may_lookup fs/namei.c:1873 [inline]
 link_path_walk+0x63c/0x900 fs/namei.c:2467
 path_openat+0x1de/0x2170 fs/namei.c:4130
 do_filp_open+0x109/0x230 fs/namei.c:4161
 do_sys_openat2+0xa6/0x110 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1463
 x64_sys_call+0x2eab/0x3000 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

value changed: 0x239f5c4a -> 0x2b53dccd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3315 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/26 15:42 upstream 72761a7e3122 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in inode_set_ctime_to_ts / inode_set_ctime_to_ts
* Struck through repros no longer work on HEAD.