INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 8929 Comm: kworker/1:3 Not tainted 4.14.224-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 register_lock_class+0x32b/0x1320 kernel/locking/lockdep.c:768
 __lock_acquire+0x167/0x3f20 kernel/locking/lockdep.c:3378
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:176
 spin_lock_bh include/linux/spinlock.h:322 [inline]
 lock_sock_nested+0x39/0x100 net/core/sock.c:2788
 l2cap_sock_teardown_cb+0x93/0x650 net/bluetooth/l2cap_sock.c:1341
 l2cap_chan_del+0xaf/0x950 net/bluetooth/l2cap_core.c:599
 l2cap_chan_close+0x103/0x870 net/bluetooth/l2cap_core.c:757
 l2cap_chan_timeout+0x143/0x2a0 net/bluetooth/l2cap_core.c:430
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP:           (null)
PGD 99528067 P4D 99528067 PUD a953f067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 8929 Comm: kworker/1:3 Not tainted 4.14.224-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
task: ffff888055e964c0 task.stack: ffff888055e98000
RIP: 0010:          (null)
RSP: 0018:ffff888055e9fc08 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 000000000000006f RCX: 1ffffffff127a03c
RDX: 1ffff11014b706f9 RSI: ffffffff8788be40 RDI: ffff8880a5b833c0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888055e964c0 R12: ffff8880b01f4d80
R13: ffff8880a5b833c0 R14: ffff88805696b280 R15: ffff8880b01f4d80
FS:  0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a1cac000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 l2cap_sock_teardown_cb+0x483/0x650 net/bluetooth/l2cap_sock.c:1366
 l2cap_chan_del+0xaf/0x950 net/bluetooth/l2cap_core.c:599
 l2cap_chan_close+0x103/0x870 net/bluetooth/l2cap_core.c:757
 l2cap_chan_timeout+0x143/0x2a0 net/bluetooth/l2cap_core.c:430
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code:  Bad RIP value.
RIP:           (null) RSP: ffff888055e9fc08
CR2: 0000000000000000
---[ end trace 108be318eb9ff011 ]---