=====================================
WARNING: bad unlock balance detected!
6.1.27-syzkaller #0 Not tainted
-------------------------------------
kworker/u5:5/3612 is trying to release lock (&conn->chan_lock) at:
[<ffffffff89946727>] l2cap_bredr_sig_cmd+0xb07/0x9fb0 net/bluetooth/l2cap_core.c:5748
but there are no more locks to release!

other info that might help us debug this:
2 locks held by kworker/u5:5/3612:
 #0: ffff88801e879938 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
 #1: ffffc900040afd20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264

stack backtrace:
CPU: 0 PID: 3612 Comm: kworker/u5:5 Not tainted 6.1.27-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_unlock_imbalance_bug+0x24e/0x2c0 kernel/locking/lockdep.c:5109
 __lock_release kernel/locking/lockdep.c:5346 [inline]
 lock_release+0x5ad/0xa20 kernel/locking/lockdep.c:5689
 __mutex_unlock_slowpath+0xde/0x750 kernel/locking/mutex.c:907
 l2cap_bredr_sig_cmd+0xb07/0x9fb0 net/bluetooth/l2cap_core.c:5748
 l2cap_sig_channel net/bluetooth/l2cap_core.c:6507 [inline]
 l2cap_recv_frame+0xa59/0x8890 net/bluetooth/l2cap_core.c:7786
 hci_acldata_packet net/bluetooth/hci_core.c:3828 [inline]
 hci_rx_work+0x39b/0xa80 net/bluetooth/hci_core.c:4063
 process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
 worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
 kthread+0x26e/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Bluetooth: Wrong link type (-22)
Bluetooth: hci0: command 0x0409 tx timeout