[moderation] [serial?] KCSAN: data-race in __tty_hangup / get_pipe_info

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 89be9a83ccf1 Linux 6.16-rc7
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=153f7f98580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c0dd0a92e88efc24
dashboard link: https://syzkaller.appspot.com/bug?extid=3eeb78314563650504d1
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [gre...@linuxfoundation.org jiri...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ddf56b16465/disk-89be9a83.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d352fc68f5dd/vmlinux-89be9a83.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2cfbbbe4e4f4/bzImage-89be9a83.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3eeb78...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __tty_hangup / get_pipe_info

write to 0xffff888118a21548 of 8 bytes by task 3803 on cpu 0:
__tty_hangup+0x1c2/0x510 drivers/tty/tty_io.c:612
tty_vhangup drivers/tty/tty_io.c:691 [inline]
tty_ioctl+0x601/0xb80 drivers/tty/tty_io.c:2732
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:893
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
x64_sys_call+0x19a8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:17
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 0xffff888118a21548 of 8 bytes by task 3798 on cpu 1:
get_pipe_info+0x2f/0x60 fs/pipe.c:1417
do_sendfile+0x2fa/0x650 fs/read_write.c:1365
__do_sys_sendfile64 fs/read_write.c:1431 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
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: 0xffffffff858a1010 -> 0xffffffff858a0f00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3798 Comm: syz.2.103 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


---
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.