syzbot

Bluetooth: hci0: Opcode 0x0c03 failed: -110
============================================
WARNING: possible recursive locking detected
6.9.0-rc5-syzkaller-00296-g5eb4573ea63d #0 Not tainted
--------------------------------------------
kworker/u9:7/5110 is trying to acquire lock:
ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: touch_wq_lockdep_map kernel/workqueue.c:3901 [inline]
ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: __flush_workqueue+0x1b0/0x1710 kernel/workqueue.c:3943

but task is already holding lock:
ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3335

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock((wq_completion)hci0);
  lock((wq_completion)hci0);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by kworker/u9:7/5110:
 #0: ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
 #0: ffff8880649da948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3335
 #1: ffffc90003a77d00 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline]
 #1: ffffc90003a77d00 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3335

stack backtrace:
CPU: 1 PID: 5110 Comm: kworker/u9:7 Not tainted 6.9.0-rc5-syzkaller-00296-g5eb4573ea63d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci0 hci_error_reset
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 touch_wq_lockdep_map kernel/workqueue.c:3901 [inline]
 __flush_workqueue+0x1c9/0x1710 kernel/workqueue.c:3943
 drain_workqueue+0xc9/0x3a0 kernel/workqueue.c:4107
 destroy_workqueue+0xba/0xc40 kernel/workqueue.c:5673
 hci_release_dev+0x169/0x16a0 net/bluetooth/hci_core.c:2808
 bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
 device_release+0x9b/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x231/0x480 lib/kobject.c:737
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>