[moderation] [fs?] KCSAN: data-race in pipe_release / pipe_wait_writable (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b290aae788e Merge tag 'sysctl-6.17-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d02ca2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fb0f7e9c3b90e79f
dashboard link: https://syzkaller.appspot.com/bug?extid=000b58a921cd9401742c
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4dd30bbcf8b1/disk-4b290aae.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e743bc007946/vmlinux-4b290aae.xz
kernel image: https://storage.googleapis.com/syzbot-assets/36356550c456/bzImage-4b290aae.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+000b58...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in pipe_release / pipe_wait_writable

read-write to 0xffff88812cec94ec of 4 bytes by task 11135 on cpu 1:
put_pipe_info fs/pipe.c:712 [inline]
pipe_release+0x16a/0x1d0 fs/pipe.c:742
__fput+0x298/0x650 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:208 [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 0xffff88812cec94ec of 4 bytes by task 11136 on cpu 0:
pipe_lock fs/pipe.c:90 [inline]
pipe_wait_writable+0x202/0x250 fs/pipe.c:1082
wait_for_space fs/splice.c:1271 [inline]
splice_file_to_pipe+0x136/0x3a0 fs/splice.c:1287
do_splice+0xc4d/0x10b0 fs/splice.c:1373
__do_splice fs/splice.c:1430 [inline]
__do_sys_splice fs/splice.c:1633 [inline]
__se_sys_splice+0x26c/0x3a0 fs/splice.c:1615
__x64_sys_splice+0x78/0x90 fs/splice.c:1615
x64_sys_call+0x28a3/0x2ff0 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: 11136 Comm: syz.2.1842 Not tainted 6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.