[moderation] [fs?] KCSAN: data-race in pipe_double_lock / pipe_release (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 334426094588 Merge tag 'for-v6.14-rc' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17fee7f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ce4e433ac2a58cc2
dashboard link: https://syzkaller.appspot.com/bug?extid=71c1e30992fb93a8774d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
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/87b82cb1c11a/disk-33442609.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a947d851daae/vmlinux-33442609.xz
kernel image: https://storage.googleapis.com/syzbot-assets/136718076367/bzImage-33442609.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+71c1e3...@syzkaller.appspotmail.com

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

read-write to 0xffff88812627842c of 4 bytes by task 5187 on cpu 0:
put_pipe_info fs/pipe.c:713 [inline]
pipe_release+0x15e/0x1c0 fs/pipe.c:743
__fput+0x2ac/0x640 fs/file_table.c:464
____fput+0x1c/0x30 fs/file_table.c:492
task_work_run+0x13a/0x1a0 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812627842c of 4 bytes by task 5188 on cpu 1:
pipe_lock fs/pipe.c:91 [inline]
pipe_double_lock+0x2e/0xa0 fs/pipe.c:111
link_pipe fs/splice.c:1873 [inline]
do_tee+0x2e9/0x940 fs/splice.c:1976
__do_sys_tee fs/splice.c:2004 [inline]
__se_sys_tee+0x93/0x130 fs/splice.c:1988
__x64_sys_tee+0x55/0x70 fs/splice.c:1988
x64_sys_call+0x2269/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:277
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000002 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5188 Comm: syz.7.22960 Not tainted 6.14.0-rc3-syzkaller-00166-g334426094588 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================


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[syzbot]

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