BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
turning off the locking correctness validator.
CPU: 0 PID: 11902 Comm: kworker/u5:27 Not tainted 5.0.0-next-20190306 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci94 hci_power_on
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 add_chain_cache kernel/locking/lockdep.c:2582 [inline]
 lookup_chain_cache_add kernel/locking/lockdep.c:2656 [inline]
 validate_chain kernel/locking/lockdep.c:2676 [inline]
 __lock_acquire.cold+0x250/0x50d kernel/locking/lockdep.c:3692
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202
 __flush_work+0x677/0x8a0 kernel/workqueue.c:3034
 flush_work+0x18/0x20 kernel/workqueue.c:3060
 hci_dev_do_open+0xa92/0x1780 net/bluetooth/hci_core.c:1543
 hci_power_on+0x10d/0x580 net/bluetooth/hci_core.c:2173
 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352