Bluetooth: hci4: hardware error 0x00
============================================
WARNING: possible recursive locking detected
6.1.93-syzkaller #0 Not tainted
--------------------------------------------
kworker/u5:4/3576 is trying to acquire lock:
ffff88807d925938 ((wq_completion)hci4){+.+.}-{0:0}, at: __flush_workqueue+0x157/0x1610 kernel/workqueue.c:2812

but task is already holding lock:
ffff88807d925938 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267

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

       CPU0
       ----
  lock((wq_completion)hci4);
  lock((wq_completion)hci4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by kworker/u5:4/3576:
 #0: ffff88807d925938 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc90003d4fd20 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267

stack backtrace:
CPU: 0 PID: 3576 Comm: kworker/u5:4 Not tainted 6.1.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: hci4 hci_error_reset
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline]
 check_deadlock kernel/locking/lockdep.c:3026 [inline]
 validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __flush_workqueue+0x170/0x1610 kernel/workqueue.c:2812
 drain_workqueue+0xc5/0x390 kernel/workqueue.c:2977
 destroy_workqueue+0x7b/0xae0 kernel/workqueue.c:4423
 hci_release_dev+0x165/0x16b0 net/bluetooth/hci_core.c:2771
 bt_host_release+0x7f/0x90 net/bluetooth/hci_sysfs.c:92
 device_release+0x91/0x1c0
 kobject_cleanup lib/kobject.c:681 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x224/0x460 lib/kobject.c:729
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>