[moderation] [fs?] KCSAN: data-race in pipe_poll / pipe_release (11)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bc9ff192a6c9 Merge tag 'net-6.16-rc6' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b9c0f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a2f5ccd29a82f8aa
dashboard link: https://syzkaller.appspot.com/bug?extid=1ea93605d0d4fb5df21d
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/cd81278ad98c/disk-bc9ff192.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1fea20ae9800/vmlinux-bc9ff192.xz
kernel image: https://storage.googleapis.com/syzbot-assets/00054e9f79c3/bzImage-bc9ff192.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1ea936...@syzkaller.appspotmail.com

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

write to 0xffff88813912fd28 of 4 bytes by task 18517 on cpu 0:
pipe_release+0xb6/0x1d0 fs/pipe.c:731
__fput+0x298/0x650 fs/file_table.c:465
____fput+0x1c/0x30 fs/file_table.c:493
task_work_run+0x131/0x1a0 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x483/0x1590 kernel/exit.c:964
do_group_exit+0x139/0x140 kernel/exit.c:1105
__do_sys_exit_group kernel/exit.c:1116 [inline]
__se_sys_exit_group kernel/exit.c:1114 [inline]
__x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1114
x64_sys_call+0x2fa4/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:232
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

read to 0xffff88813912fd28 of 4 bytes by task 3289 on cpu 1:
pipe_poll+0x16d/0x250 fs/pipe.c:689
vfs_poll include/linux/poll.h:82 [inline]
select_poll_one fs/select.c:480 [inline]
do_select+0x8ee/0xf50 fs/select.c:536
core_sys_select+0x3d7/0x6e0 fs/select.c:677
do_pselect fs/select.c:759 [inline]
__do_sys_pselect6 fs/select.c:802 [inline]
__se_sys_pselect6+0x216/0x280 fs/select.c:793
__x64_sys_pselect6+0x78/0x90 fs/select.c:793
x64_sys_call+0x1caa/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:271
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: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3289 Comm: syz-executor Not tainted 6.16.0-rc5-syzkaller-00121-gbc9ff192a6c9 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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[syzbot]

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