syzbot

=====================================
WARNING: bad unlock balance detected!
5.15.110-syzkaller #0 Not tainted
-------------------------------------
kworker/u5:1/3964 is trying to release lock (&conn->chan_lock) at:
[<ffff800010cd9104>] 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/u5:1/3964:
 #0: ffff0000c899e138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2279
 #1: ffff80001c4c7c00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2281

stack backtrace:
CPU: 0 PID: 3964 Comm: kworker/u5:1 Not tainted 5.15.110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: hci0 hci_rx_work
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_unlock_imbalance_bug+0x250/0x2a4 kernel/locking/lockdep.c:5064
 lock_release+0x4b8/0xa1c kernel/locking/lockdep.c:5642
 __mutex_unlock_slowpath+0xe0/0x6d4 kernel/locking/mutex.c:851
 mutex_unlock+0x8c/0xe0 kernel/locking/mutex.c:536
 l2cap_disconnect_rsp+0x210/0x30c net/bluetooth/l2cap_core.c:4697
 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+0x188c/0x6a48 net/bluetooth/l2cap_core.c:7796
 l2cap_recv_acldata+0x4f4/0x163c net/bluetooth/l2cap_core.c:8504
 hci_acldata_packet net/bluetooth/hci_core.c:4967 [inline]
 hci_rx_work+0x3b0/0x6d0 net/bluetooth/hci_core.c:5158
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2306
 worker_thread+0x910/0x1034 kernel/workqueue.c:2453
 kthread+0x37c/0x45c kernel/kthread.c:319
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870