===================================== WARNING: bad unlock balance detected! 5.15.181-syzkaller #0 Not tainted ------------------------------------- kworker/u5:1/4100 is trying to release lock (&chan->lock) at: [] l2cap_chan_unlock include/net/bluetooth/l2cap.h:860 [inline] [] l2cap_conless_channel net/bluetooth/l2cap_core.c:7767 [inline] [] l2cap_recv_frame+0x934/0x61a4 net/bluetooth/l2cap_core.c:7820 but there are no more locks to release! other info that might help us debug this: 2 locks held by kworker/u5:1/4100: #0: ffff0000d0fab938 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x678/0x1140 kernel/workqueue.c:2283 #1: ffff80001f777c00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6b8/0x1140 kernel/workqueue.c:2285 stack backtrace: CPU: 1 PID: 4100 Comm: kworker/u5:1 Not tainted 5.15.181-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Workqueue: hci0 hci_rx_work Call trace: dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_unlock_imbalance_bug+0x11c/0x160 kernel/locking/lockdep.c:5065 __lock_release kernel/locking/lockdep.c:5302 [inline] lock_release+0x454/0x8e8 kernel/locking/lockdep.c:5643 __mutex_unlock_slowpath+0xc0/0x5d8 kernel/locking/mutex.c:851 mutex_unlock+0x90/0xec kernel/locking/mutex.c:536 l2cap_chan_unlock include/net/bluetooth/l2cap.h:860 [inline] l2cap_conless_channel net/bluetooth/l2cap_core.c:7767 [inline] l2cap_recv_frame+0x934/0x61a4 net/bluetooth/l2cap_core.c:7820 l2cap_recv_acldata+0x4dc/0x137c net/bluetooth/l2cap_core.c:8532 hci_acldata_packet net/bluetooth/hci_core.c:4973 [inline] hci_rx_work+0x3a0/0x880 net/bluetooth/hci_core.c:5165 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310 worker_thread+0x8f4/0x101c kernel/workqueue.c:2457 kthread+0x374/0x454 kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870