syzbot


KCSAN: data-race in __dentry_kill / __dentry_kill (7)

Status: moderation: reported on 2026/02/02 12:42
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+32c4ce311ae1ea106e44@syzkaller.appspotmail.com
First crash: 41d, last: 9d03h
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
1fc03653-f781-4f9b-88b9-0764266a73d2 repro KCSAN: data-race in __dentry_kill / __dentry_kill (7) 2026/03/07 03:29 2026/03/07 03:29 2026/03/07 03:37 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
982b89e5-2f52-49a5-a022-9678d450ee0d assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in __dentry_kill / __dentry_kill (7) 2026/02/02 12:41 2026/02/02 12:41 2026/02/02 12:55 2186dcabcd743737b50c1a9f99a8bf0d3a5a7914
93880a73-eb05-473c-9a94-3f1f0d0a66b5 assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in __dentry_kill / __dentry_kill (7) 2026/02/02 12:41 2026/02/02 12:41 2026/02/02 13:10 63a5f77ffe6c631f8781efb082e741722cdf8c6a+
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 (6) fs 6 7 204d 275d 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 640d 640d 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 581d 581d 0/29 auto-obsoleted due to no activity on 2024/09/15 09:01
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (5) fs 6 1 444d 444d 0/29 auto-obsoleted due to no activity on 2025/02/21 02:11
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (4) fs 6 2 504d 510d 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 704d 704d 0/29 auto-obsoleted due to no activity on 2024/05/15 11:32

Sample crash report:
kexec: Could not allocate control_code_buffer
==================================================================
BUG: KCSAN: data-race in __dentry_kill / __dentry_kill

write to 0xffff88811aea6e40 of 4 bytes by task 3310 on cpu 1:
 d_lru_del fs/dcache.c:504 [inline]
 __dentry_kill+0xa8/0x460 fs/dcache.c:665
 finish_dput+0x2b/0x200 fs/dcache.c:879
 dput+0x52/0x60 fs/dcache.c:928
 proc_invalidate_siblings_dcache+0x1d0/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3481
 release_task+0x988/0xb60 kernel/exit.c:291
 wait_task_zombie kernel/exit.c:1280 [inline]
 wait_consider_task+0x1160/0x1670 kernel/exit.c:1507
 do_wait_thread kernel/exit.c:1570 [inline]
 __do_wait+0xf9/0x510 kernel/exit.c:1688
 do_wait+0xb6/0x260 kernel/exit.c:1722
 kernel_wait4+0x19f/0x210 kernel/exit.c:1881
 __do_sys_wait4 kernel/exit.c:1909 [inline]
 __se_sys_wait4 kernel/exit.c:1905 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1905
 x64_sys_call+0x2aee/0x3020 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811aea6e40 of 4 bytes by task 6340 on cpu 0:
 dentry_unlist fs/dcache.c:640 [inline]
 __dentry_kill+0x25c/0x460 fs/dcache.c:684
 finish_dput+0x2b/0x200 fs/dcache.c:879
 dput+0x52/0x60 fs/dcache.c:928
 proc_invalidate_siblings_dcache+0x1d0/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3481
 release_task+0x988/0xb60 kernel/exit.c:291
 exit_notify kernel/exit.c:777 [inline]
 do_exit+0xda4/0x1600 kernel/exit.c:988
 do_group_exit+0xfe/0x140 kernel/exit.c:1118
 get_signal+0xe54/0xf60 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x249/0x370 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0014000c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6340 Comm: syz.1.16064 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/07 00:28 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
2026/02/22 08:38 upstream fa5c82f4d2bb 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
2026/02/20 23:52 upstream a95f71ad3e2e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
2026/02/08 02:37 upstream e7aa57247700 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
2026/02/02 12:41 upstream 18f7fcd5e69a 018ebef2 .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.