syzbot

=====================================
WARNING: bad unlock balance detected!
5.15.167-syzkaller #0 Not tainted
-------------------------------------
kworker/u5:2/3568 is trying to release lock (&chan->lock) at:
[<ffffffff895b621f>] l2cap_chan_unlock include/net/bluetooth/l2cap.h:860 [inline]
[<ffffffff895b621f>] l2cap_conless_channel net/bluetooth/l2cap_core.c:7770 [inline]
[<ffffffff895b621f>] l2cap_recv_frame+0x136f/0x8ae0 net/bluetooth/l2cap_core.c:7823
but there are no more locks to release!

other info that might help us debug this:
2 locks held by kworker/u5:2/3568:
 #0: ffff8880232fd938 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90002c77d20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285

stack backtrace:
CPU: 0 PID: 3568 Comm: kworker/u5:2 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_unlock_imbalance_bug+0x248/0x2b0 kernel/locking/lockdep.c:5065
 __lock_release kernel/locking/lockdep.c:5302 [inline]
 lock_release+0x596/0x9a0 kernel/locking/lockdep.c:5643
 __mutex_unlock_slowpath+0xde/0x750 kernel/locking/mutex.c:851
 l2cap_chan_unlock include/net/bluetooth/l2cap.h:860 [inline]
 l2cap_conless_channel net/bluetooth/l2cap_core.c:7770 [inline]
 l2cap_recv_frame+0x136f/0x8ae0 net/bluetooth/l2cap_core.c:7823
 hci_acldata_packet net/bluetooth/hci_core.c:4969 [inline]
 hci_rx_work+0x48f/0x990 net/bluetooth/hci_core.c:5160
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287