[moderation] [fs?] KCSAN: data-race in pipe_release / pipe_wait_readable (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e927c520e1ba Merge tag 'loongarch-fixes-6.18-1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1088c914580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2e0bc0ae94545f7
dashboard link: https://syzkaller.appspot.com/bug?extid=69b7188cba763e6a521d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
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/971519f3b046/disk-e927c520.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/989c293d066d/vmlinux-e927c520.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4c113f37585c/bzImage-e927c520.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+69b718...@syzkaller.appspotmail.com

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

read-write to 0xffff88811d7badec of 4 bytes by task 8162 on cpu 0:
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+0x131/0x1a0 kernel/task_work.c:227
get_signal+0xe12/0xf70 kernel/signal.c:2807
arch_do_signal_or_restart+0x96/0x440 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x77/0x110 kernel/entry/common.c:40
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 0xffff88811d7badec of 4 bytes by task 8170 on cpu 1:
pipe_lock fs/pipe.c:90 [inline]
pipe_wait_readable+0x1c2/0x210 fs/pipe.c:1077
ipipe_prep fs/splice.c:1669 [inline]
do_tee+0x1fc/0x910 fs/splice.c:1963
__do_sys_tee fs/splice.c:1995 [inline]
__se_sys_tee+0x93/0x130 fs/splice.c:1979
__x64_sys_tee+0x55/0x70 fs/splice.c:1979
x64_sys_call+0xb7d/0x3000 arch/x86/include/generated/asm/syscalls_64.h:277
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: 1 UID: 0 PID: 8170 Comm: syz.0.1654 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================


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