syzbot


KCSAN: data-race in pipe_lock / pipe_release (16)

Status: moderation: reported on 2025/07/23 19:58
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+c8a8a00a347cf8270583@syzkaller.appspotmail.com
First crash: 50d, last: 25d
Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in pipe_lock / pipe_release (5) fs 6 1 1368d 1368d 0/29 auto-closed as invalid on 2022/01/18 04:35
upstream KCSAN: data-race in pipe_lock / pipe_release (8) fs 6 1 1116d 1116d 0/29 auto-closed as invalid on 2022/09/27 07:59
upstream KCSAN: data-race in pipe_lock / pipe_release (13) fs 6 1 571d 571d 0/29 auto-obsoleted due to no activity on 2024/03/25 04:35
upstream KCSAN: data-race in pipe_lock / pipe_release (15) fs 6 3 230d 303d 0/29 auto-obsoleted due to no activity on 2025/03/21 15:25
upstream KCSAN: data-race in pipe_lock / pipe_release (4) fs 6 1 1629d 1629d 0/29 auto-closed as invalid on 2021/05/02 03:19
upstream KCSAN: data-race in pipe_lock / pipe_release (11) fs 6 1 717d 717d 0/29 auto-obsoleted due to no activity on 2023/10/31 07:05
upstream KCSAN: data-race in pipe_lock / pipe_release (14) fs 6 2 460d 462d 0/29 auto-obsoleted due to no activity on 2024/07/14 01:56
upstream KCSAN: data-race in pipe_lock / pipe_release (6) fs 6 2 1294d 1297d 0/29 auto-closed as invalid on 2022/04/01 19:16
upstream KCSAN: data-race in pipe_lock / pipe_release (9) fs 6 6 861d 991d 0/29 auto-obsoleted due to no activity on 2023/06/09 03:35
upstream KCSAN: data-race in pipe_lock / pipe_release fs 6 2 1894d 1911d 0/29 auto-closed as invalid on 2020/08/09 18:16
upstream KCSAN: data-race in pipe_lock / pipe_release (3) fs 6 1 1786d 1786d 0/29 auto-closed as invalid on 2020/11/25 12:55
upstream KCSAN: data-race in pipe_lock / pipe_release (12) fs 6 1 625d 625d 0/29 auto-obsoleted due to no activity on 2024/01/31 07:04
upstream KCSAN: data-race in pipe_lock / pipe_release (7) fs 6 2 1226d 1254d 0/29 auto-closed as invalid on 2022/06/08 19:34
upstream KCSAN: data-race in pipe_lock / pipe_release (10) fs 6 2 798d 819d 0/29 auto-obsoleted due to no activity on 2023/08/10 23:17
upstream KCSAN: data-race in pipe_lock / pipe_release (2) fs 6 1 1837d 1837d 0/29 auto-closed as invalid on 2020/10/06 00:08

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

read-write to 0xffff888131f75eac of 4 bytes by task 24135 on cpu 1:
 put_pipe_info fs/pipe.c:712 [inline]
 pipe_release+0x16a/0x1d0 fs/pipe.c:742
 __fput+0x29b/0x650 fs/file_table.c:468
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe4/0x100 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888131f75eac of 4 bytes by task 24138 on cpu 0:
 pipe_lock+0x17/0x50 fs/pipe.c:90
 vmsplice_to_user fs/splice.c:1517 [inline]
 __do_sys_vmsplice fs/splice.c:1609 [inline]
 __se_sys_vmsplice+0x21f/0xee0 fs/splice.c:1577
 __x64_sys_vmsplice+0x55/0x70 fs/splice.c:1577
 x64_sys_call+0x1dde/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:279
 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: 0x00000002 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24138 Comm: syz.6.6549 Tainted: G        W           6.17.0-rc1-syzkaller-00214-g99bade344cfa #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/17 19:16 upstream 99bade344cfa 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pipe_lock / pipe_release
2025/07/23 19:57 upstream 01a412d06bc5 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pipe_lock / pipe_release
* Struck through repros no longer work on HEAD.