syzbot


KCSAN: data-race in __dentry_kill / __dentry_kill (4)

Status: moderation: reported on 2024/10/21 06:27
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+d2d8117208036e13d980@syzkaller.appspotmail.com
First crash: 45d, last: 39d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (2) fs 1 175d 175d 0/28 auto-obsoleted due to no activity on 2024/07/18 14:41
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (3) fs 1 116d 116d 0/28 auto-obsoleted due to no activity on 2024/09/15 09:01
upstream KCSAN: data-race in __dentry_kill / __dentry_kill fs 1 239d 239d 0/28 auto-obsoleted due to no activity on 2024/05/15 11:32

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

write to 0xffff888106f32c00 of 4 bytes by task 3925 on cpu 0:
 d_lru_del fs/dcache.c:449 [inline]
 __dentry_kill+0xa3/0x4c0 fs/dcache.c:610
 dput+0x5c/0xd0 fs/dcache.c:857
 lookup_fast+0x25c/0x2a0 fs/namei.c:1698
 walk_component fs/namei.c:2049 [inline]
 link_path_walk+0x464/0x820 fs/namei.c:2418
 path_openat+0x1af/0x1fa0 fs/namei.c:3929
 do_filp_open+0xf7/0x200 fs/namei.c:3960
 do_sys_openat2+0xab/0x120 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1441
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106f32c00 of 4 bytes by task 3778 on cpu 1:
 dentry_unlist fs/dcache.c:585 [inline]
 __dentry_kill+0x2af/0x4c0 fs/dcache.c:629
 dput+0x5c/0xd0 fs/dcache.c:857
 lookup_fast+0x25c/0x2a0 fs/namei.c:1698
 walk_component fs/namei.c:2049 [inline]
 link_path_walk+0x464/0x820 fs/namei.c:2418
 path_openat+0x1af/0x1fa0 fs/namei.c:3929
 do_filp_open+0xf7/0x200 fs/namei.c:3960
 do_sys_openat2+0xab/0x120 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1441
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00280004 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3778 Comm: udevd Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
udevd[3778]: inotify_add_watch(7, /dev/loop1p1, 10) failed: No such file or directory

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/27 05:34 upstream 850925a8133c 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
2024/10/21 06:26 upstream 42f7652d3eb5 cd6fc0a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
* Struck through repros no longer work on HEAD.