INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 1516 Comm: kworker/0:8 Not tainted 5.9.0-rc7-next-20201002-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:77 [inline]
 dump_stack+0x198/0x1fb lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:909 [inline]
 register_lock_class+0x157d/0x1630 kernel/locking/lockdep.c:1221
 __lock_acquire+0xfe/0x56d0 kernel/locking/lockdep.c:4696
 lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5419
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 lock_sock_nested+0x3b/0x110 net/core/sock.c:3041
 l2cap_sock_teardown_cb+0x89/0x400 net/bluetooth/l2cap_sock.c:1520
 l2cap_chan_del+0xad/0x1300 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x118/0xb10 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x173/0x450 net/bluetooth/l2cap_core.c:436
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 561f4067 P4D 561f4067 PUD 561f5067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 1516 Comm: kworker/0:8 Not tainted 5.9.0-rc7-next-20201002-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffffc900083a7b70 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888089da3000 RCX: ffffffff87539184
RDX: 1ffff110113b468c RSI: ffffffff8753940a RDI: ffff888089da3000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000009 R11: 000000000000015e R12: 000000000000006f
R13: ffff88809e902000 R14: ffff88809e902020 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000561f3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 l2cap_sock_teardown_cb+0x371/0x400 net/bluetooth/l2cap_sock.c:1545
 l2cap_chan_del+0xad/0x1300 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x118/0xb10 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x173/0x450 net/bluetooth/l2cap_core.c:436
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
CR2: 0000000000000000
---[ end trace abd9a6e5516b5c28 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffffc900083a7b70 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888089da3000 RCX: ffffffff87539184
RDX: 1ffff110113b468c RSI: ffffffff8753940a RDI: ffff888089da3000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000009 R11: 000000000000015e R12: 000000000000006f
R13: ffff88809e902000 R14: ffff88809e902020 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000561f3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400