INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.11.0-rc4-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:79 [inline]
 dump_stack+0xa3/0xc8 lib/dump_stack.c:120
 assign_lock_key kernel/locking/lockdep.c:935 [inline]
 register_lock_class+0x575/0x580 kernel/locking/lockdep.c:1247
 __lock_acquire+0x75/0x1770 kernel/locking/lockdep.c:4711
 lock_acquire+0xf9/0x420 kernel/locking/lockdep.c:5437
 __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+0x2c/0x90 net/core/sock.c:3049
 l2cap_sock_teardown_cb+0x1f/0x130 net/bluetooth/l2cap_sock.c:1520
 l2cap_chan_del+0x35/0x320 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0xfb/0x270 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x70/0xe0 net/bluetooth/l2cap_core.c:436
 process_one_work+0x293/0x600 kernel/workqueue.c:2275
 worker_thread+0x38/0x380 kernel/workqueue.c:2421
 kthread+0x145/0x170 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 0 P4D 0 
Oops: 0010 [#1] PREEMPT SMP
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.11.0-rc4-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: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90000047d80 EFLAGS: 00010246
RAX: 0000000000000005 RBX: 000000000000006f RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffffffff840ddc4e RDI: ffff88811481d800
RBP: ffff88811481d800 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000a632 R11: 000000000000d000 R12: 0000000000000000
R13: ffff8881124a9800 R14: ffff8881124a9910 R15: ffff8881124a9918
FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000010814d004 CR4: 00000000001706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 l2cap_sock_teardown_cb+0x127/0x130 net/bluetooth/l2cap_sock.c:1545
 l2cap_chan_del+0x35/0x320 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0xfb/0x270 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x70/0xe0 net/bluetooth/l2cap_core.c:436
 process_one_work+0x293/0x600 kernel/workqueue.c:2275
 worker_thread+0x38/0x380 kernel/workqueue.c:2421
 kthread+0x145/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
CR2: 0000000000000000
---[ end trace d29bbcd1f757ab75 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90000047d80 EFLAGS: 00010246
RAX: 0000000000000005 RBX: 000000000000006f RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffffffff840ddc4e RDI: ffff88811481d800
RBP: ffff88811481d800 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000a632 R11: 000000000000d000 R12: 0000000000000000
R13: ffff8881124a9800 R14: ffff8881124a9910 R15: ffff8881124a9918
FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000010814d004 CR4: 00000000001706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400