syzbot


KCSAN: data-race in pipe_release / pipe_wait_writable (4)

Status: moderation: reported on 2025/10/03 11:20
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+7b22d7a6bd02b165d9fa@syzkaller.appspotmail.com
First crash: 15h09m, last: 15h09m
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in pipe_release / pipe_wait_writable fs 6 1 1354d 1354d 0/29 auto-closed as invalid on 2022/02/23 01:29
upstream KCSAN: data-race in pipe_release / pipe_wait_writable (2) fs 6 1 1059d 1059d 0/29 auto-obsoleted due to no activity on 2022/12/15 02:24
upstream KCSAN: data-race in pipe_release / pipe_wait_writable (3) fs 6 2 64d 65d 0/29 auto-obsoleted due to no activity on 2025/09/25 08:20

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

read-write to 0xffff888117fd196c of 4 bytes by task 7186 on cpu 1:
 put_pipe_info fs/pipe.c:714 [inline]
 pipe_release+0x16a/0x1d0 fs/pipe.c:744
 __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+0xed/0x110 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 0xffff888117fd196c of 4 bytes by task 7163 on cpu 0:
 pipe_lock fs/pipe.c:90 [inline]
 pipe_wait_writable+0x202/0x250 fs/pipe.c:1084
 wait_for_space fs/splice.c:1274 [inline]
 splice_file_to_pipe+0x12d/0x390 fs/splice.c:1290
 do_splice+0xc48/0x10b0 fs/splice.c:1376
 __do_splice fs/splice.c:1433 [inline]
 __do_sys_splice fs/splice.c:1636 [inline]
 __se_sys_splice+0x26c/0x3a0 fs/splice.c:1618
 __x64_sys_splice+0x78/0x90 fs/splice.c:1618
 x64_sys_call+0x28a7/0x3000 arch/x86/include/generated/asm/syscalls_64.h:276
 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: 7163 Comm: syz.2.1185 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/03 11:19 upstream e406d57be7bd 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pipe_release / pipe_wait_writable
* Struck through repros no longer work on HEAD.