[moderation] [fs?] KCSAN: data-race in pipe_poll / pipe_release (13)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: faeab166167f Merge tag 'pinctrl-v7.1-1' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14419702580000
kernel config: https://syzkaller.appspot.com/x/.config?x=544ec71e02cb3732
dashboard link: https://syzkaller.appspot.com/bug?extid=e30a8943954071025142
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
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/bcd193e430fd/disk-faeab166.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5899e5f0649a/vmlinux-faeab166.xz
kernel image: https://storage.googleapis.com/syzbot-assets/57aab7e47902/bzImage-faeab166.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e30a89...@syzkaller.appspotmail.com

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

write to 0xffff88812e1fbd20 of 4 bytes by task 11018 on cpu 1:
pipe_release+0xb6/0x1d0 fs/pipe.c:733
__fput+0x29b/0x630 fs/file_table.c:510
____fput+0x1c/0x30 fs/file_table.c:538
task_work_run+0x130/0x1a0 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x4ae/0x1530 kernel/exit.c:975
do_group_exit+0x138/0x140 kernel/exit.c:1117
__do_sys_exit_group kernel/exit.c:1128 [inline]
__se_sys_exit_group kernel/exit.c:1126 [inline]
__x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1126
x64_sys_call+0x3008/0x3020 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812e1fbd20 of 4 bytes by task 3302 on cpu 0:
pipe_poll+0x16d/0x250 fs/pipe.c:691
vfs_poll include/linux/poll.h:82 [inline]
select_poll_one fs/select.c:480 [inline]
do_select+0x94e/0xfa0 fs/select.c:536
core_sys_select+0x45d/0x730 fs/select.c:677
do_pselect fs/select.c:759 [inline]
__do_sys_pselect6 fs/select.c:798 [inline]
__se_sys_pselect6+0x23c/0x2a0 fs/select.c:789
__x64_sys_pselect6+0x78/0x90 fs/select.c:789
x64_sys_call+0x8d5/0x3020 arch/x86/include/generated/asm/syscalls_64.h:271
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3302 Comm: syz-executor Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
==================================================================


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