syzbot

Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
Bluetooth: hci0: unexpected cc 0x0c25 length: 249 > 3
Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
=====================================
WARNING: bad unlock balance detected!
6.1.26-syzkaller #0 Not tainted
-------------------------------------
kworker/u5:2/3548 is trying to release lock (&conn->chan_lock) at:
[<ffffffff89937f5c>] l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:6426 [inline]
[<ffffffff89937f5c>] l2cap_le_sig_channel net/bluetooth/l2cap_core.c:6464 [inline]
[<ffffffff89937f5c>] l2cap_recv_frame+0x1fcc/0x8890 net/bluetooth/l2cap_core.c:7796
but there are no more locks to release!

other info that might help us debug this:
2 locks held by kworker/u5:2/3548:
 #0: ffff8880764cb138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
 #1: ffffc90003a7fd20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264

stack backtrace:
CPU: 0 PID: 3548 Comm: kworker/u5:2 Not tainted 6.1.26-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_le_sig_cmd net/bluetooth/l2cap_core.c:6426 [inline]
 l2cap_le_sig_channel net/bluetooth/l2cap_core.c:6464 [inline]
 l2cap_recv_frame+0x1fcc/0x8890 net/bluetooth/l2cap_core.c:7796
 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