[moderation] [bluetooth?] KCSAN: data-race in hci_uart_open / hci_uart_tty_close

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dbfc6422a34d Merge tag 'x86_urgent_for_v6.18_rc3' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10372c92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=15383e23338541bf
dashboard link: https://syzkaller.appspot.com/bug?extid=072dd099702efe664172
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [linux-b...@vger.kernel.org linux-...@vger.kernel.org luiz....@gmail.com mar...@holtmann.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6cbfe0bac173/disk-dbfc6422.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e3788a82499a/vmlinux-dbfc6422.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c92497a56387/bzImage-dbfc6422.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+072dd0...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in hci_uart_open / hci_uart_tty_close

write to 0xffff88813ae41410 of 8 bytes by task 20904 on cpu 1:
hci_uart_close drivers/bluetooth/hci_ldisc.c:269 [inline]
hci_uart_tty_close+0x61/0x170 drivers/bluetooth/hci_ldisc.c:545
tty_ldisc_close drivers/tty/tty_ldisc.c:455 [inline]
tty_ldisc_kill+0x8d/0x140 drivers/tty/tty_ldisc.c:613
tty_ldisc_hangup+0x2fa/0x370 drivers/tty/tty_ldisc.c:729
__tty_hangup+0x3c2/0x540 drivers/tty/tty_io.c:621
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:597 [inline]
__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x1816/0x3000 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

write to 0xffff88813ae41410 of 8 bytes by task 3557 on cpu 0:
hci_uart_open+0x19/0x30 drivers/bluetooth/hci_ldisc.c:258
hci_dev_open_sync+0x186/0x2290 net/bluetooth/hci_sync.c:5122
hci_dev_do_open net/bluetooth/hci_core.c:430 [inline]
hci_power_on+0xef/0x390 net/bluetooth/hci_core.c:959
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
worker_thread+0x582/0x770 kernel/workqueue.c:3427
kthread+0x489/0x510 kernel/kthread.c:463
ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0xffffffff83e189e0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3557 Comm: kworker/u9:1 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: hci0 hci_power_on
==================================================================
Bluetooth: hci0: Opcode 0x1003 failed: -110


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