=====================================
WARNING: bad unlock balance detected!
6.1.26-syzkaller #0 Not tainted
-------------------------------------
kworker/u5:6/4270 is trying to release lock (&conn->chan_lock) at:
[<ffff800011388d28>] l2cap_disconnect_rsp+0x210/0x30c net/bluetooth/l2cap_core.c:4697
but there are no more locks to release!

other info that might help us debug this:
2 locks held by kworker/u5:6/4270:
 #0: ffff0000c16dd938 ((wq_completion)hci4#2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2262
 #1: ffff80001db77c20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2264

stack backtrace:
CPU: 0 PID: 4270 Comm: kworker/u5:6 Not tainted 6.1.26-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Workqueue: hci4 hci_rx_work
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_unlock_imbalance_bug+0x250/0x2a4 kernel/locking/lockdep.c:5109
 lock_release+0x4dc/0xa50 kernel/locking/lockdep.c:5689
 __mutex_unlock_slowpath+0xe0/0x6cc kernel/locking/mutex.c:907
 mutex_unlock+0x24/0x30 kernel/locking/mutex.c:543
 l2cap_disconnect_rsp+0x210/0x30c net/bluetooth/l2cap_core.c:4697
 l2cap_bredr_sig_cmd+0x974/0x7e94 net/bluetooth/l2cap_core.c:5748
 l2cap_sig_channel net/bluetooth/l2cap_core.c:6507 [inline]
 l2cap_recv_frame+0x83c/0x6a14 net/bluetooth/l2cap_core.c:7786
 l2cap_recv_acldata+0x4f4/0x163c net/bluetooth/l2cap_core.c:8504
 hci_acldata_packet net/bluetooth/hci_core.c:3828 [inline]
 hci_rx_work+0x2cc/0x8b8 net/bluetooth/hci_core.c:4063
 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2289
 worker_thread+0x8e4/0xfec kernel/workqueue.c:2436
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860