KCSAN: data-race in __dentry_kill / __dentry_kill (5)

Status: auto-obsoleted due to no activity on 2025/02/21 02:11
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+73ebe3aa4cb29bad2009@syzkaller.appspotmail.com
First crash: 574d, last: 574d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (7) prio:high fs 6 17 41d 171d 0/29 moderation: reported on 2026/02/02 12:42
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (6) fs 6 7 334d 405d 0/29 auto-obsoleted due to no activity on 2025/10/18 15:44
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (2) fs 6 1 770d 770d 0/29 auto-obsoleted due to no activity on 2024/07/18 14:41
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (3) fs 6 1 712d 712d 0/29 auto-obsoleted due to no activity on 2024/09/15 09:01
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (4) fs 6 2 635d 641d 0/29 auto-obsoleted due to no activity on 2024/12/22 05:35
upstream KCSAN: data-race in __dentry_kill / __dentry_kill fs 6 1 834d 834d 0/29 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 0xffff88811e4a80c0 of 4 bytes by task 2999 on cpu 1:
 d_lru_del fs/dcache.c:459 [inline]
 __dentry_kill+0xa3/0x4c0 fs/dcache.c:620
 dput+0x5c/0xd0 fs/dcache.c:867
 lookup_fast+0x25c/0x2a0 fs/namei.c:1757
 walk_component+0x3f/0x230 fs/namei.c:2108
 lookup_last fs/namei.c:2610 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2634
 filename_lookup+0x150/0x340 fs/namei.c:2663
 do_readlinkat+0x89/0x210 fs/stat.c:562
 __do_sys_readlink fs/stat.c:599 [inline]
 __se_sys_readlink fs/stat.c:596 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:596
 x64_sys_call+0x28ba/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:90
 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 0xffff88811e4a80c0 of 4 bytes by task 21348 on cpu 0:
 dentry_unlist fs/dcache.c:595 [inline]
 __dentry_kill+0x2af/0x4c0 fs/dcache.c:639
 dput+0x5c/0xd0 fs/dcache.c:867
 lookup_fast+0x25c/0x2a0 fs/namei.c:1757
 walk_component+0x3f/0x230 fs/namei.c:2108
 lookup_last fs/namei.c:2610 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2634
 filename_lookup+0x150/0x340 fs/namei.c:2663
 user_path_at+0x3c/0x120 fs/namei.c:3070
 do_faccessat+0x396/0x640 fs/open.c:485
 __do_sys_faccessat2 fs/open.c:539 [inline]
 __se_sys_faccessat2 fs/open.c:536 [inline]
 __x64_sys_faccessat2+0x51/0x60 fs/open.c:536
 x64_sys_call+0x15bc/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:440
 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: 0 UID: 0 PID: 21348 Comm: udevd Not tainted 6.13.0-rc4-syzkaller-00054-gd6ef8b40d075 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/27 02:10 upstream d6ef8b40d075 d3ccff63 .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.