[moderation] [serial?] KCSAN: data-race in __se_sys_ioctl / __tty_hangup (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8dfce8991b95 Merge tag 'pinctrl-v6.19-3' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15341694580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e27f4588a0f2183
dashboard link: https://syzkaller.appspot.com/bug?extid=3e4f2cf9b4d6658b0889
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
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/ab10328ed06d/disk-8dfce899.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c425cfa5cf81/vmlinux-8dfce899.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1fcaf7587049/bzImage-8dfce899.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3e4f2c...@syzkaller.appspotmail.com

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

write to 0xffff88813a38de48 of 8 bytes by task 3417 on cpu 0:
__tty_hangup+0x1ef/0x540 drivers/tty/tty_io.c:612
do_tty_hangup+0x1e/0x30 drivers/tty/tty_io.c:663
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421
kthread+0x488/0x510 kernel/kthread.c:463
ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff88813a38de48 of 8 bytes by task 7977 on cpu 1:
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xa1/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffff85aa61c0 -> 0xffffffff85aa60b0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7977 Comm: syz.8.1114 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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