INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 11140 Comm: kworker/1:12 Not tainted 5.12.0-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+0x141/0x1d7 lib/dump_stack.c:120
 assign_lock_key kernel/locking/lockdep.c:935 [inline]
 register_lock_class+0x106b/0x1170 kernel/locking/lockdep.c:1247
 __lock_acquire+0x106/0x54c0 kernel/locking/lockdep.c:4779
 lock_acquire kernel/locking/lockdep.c:5510 [inline]
 lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475
 __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+0x40/0x120 net/core/sock.c:3063
 l2cap_sock_teardown_cb+0xa1/0x660 net/bluetooth/l2cap_sock.c:1520
 l2cap_chan_del+0xbc/0xa80 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x1bc/0xaf0 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x17e/0x2f0 net/bluetooth/l2cap_core.c:436
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
==================================================================
BUG: KASAN: use-after-free in l2cap_sock_teardown_cb+0x5c9/0x660 net/bluetooth/l2cap_sock.c:1522
Read of size 8 at addr ffff88801429f4c8 by task kworker/1:12/11140

CPU: 1 PID: 11140 Comm: kworker/1:12 Not tainted 5.12.0-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+0x141/0x1d7 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2c6 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 l2cap_sock_teardown_cb+0x5c9/0x660 net/bluetooth/l2cap_sock.c:1522
 l2cap_chan_del+0xbc/0xa80 net/bluetooth/l2cap_core.c:618
 l2cap_chan_close+0x1bc/0xaf0 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x17e/0x2f0 net/bluetooth/l2cap_core.c:436
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the page:
page:ffffea000050a7c0 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1429f
flags: 0xfff00000000000()
raw: 00fff00000000000 ffffea0001eaf908 ffff88813fffb840 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88801429f380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801429f400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88801429f480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88801429f500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801429f580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================