INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 13305 Comm: kworker/1:21 Not tainted 5.10.0-rc3-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+0x107/0x163 lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:933 [inline]
 register_lock_class+0x12ff/0x14e0 kernel/locking/lockdep.c:1245
 __lock_acquire+0xfe/0x5590 kernel/locking/lockdep.c:4710
 lock_acquire kernel/locking/lockdep.c:5436 [inline]
 lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5401
 __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:3036
 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+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
==================================================================
BUG: KASAN: use-after-free in l2cap_sock_teardown_cb+0x5c9/0x660 net/bluetooth/l2cap_sock.c:1522
Read of size 8 at addr ffff88808ce154c8 by task kworker/1:21/13305

CPU: 1 PID: 13305 Comm: kworker/1:21 Not tainted 5.10.0-rc3-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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 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+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Allocated by task 1671:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 ops_init+0xfb/0x470 net/core/net_namespace.c:142
 setup_net+0x2d8/0x850 net/core/net_namespace.c:342
 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:483
 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x445/0x8e0 kernel/fork.c:2949
 __do_sys_unshare kernel/fork.c:3017 [inline]
 __se_sys_unshare kernel/fork.c:3015 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3015
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 13489:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0x102/0x140 mm/kasan/common.c:422
 slab_free_hook mm/slub.c:1544 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577
 slab_free mm/slub.c:3142 [inline]
 kfree+0xdb/0x360 mm/slub.c:4124
 ops_free net/core/net_namespace.c:166 [inline]
 ops_free_list.part.0+0x271/0x3d0 net/core/net_namespace.c:199
 ops_free_list net/core/net_namespace.c:197 [inline]
 cleanup_net+0x591/0xa00 net/core/net_namespace.c:608
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

The buggy address belongs to the object at ffff88808ce15000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1224 bytes inside of
 2048-byte region [ffff88808ce15000, ffff88808ce15800)
The buggy address belongs to the page:
page:00000000b1837f5a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8ce10
head:00000000b1837f5a order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000200000001 ffff888010042000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808ce15380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ce15400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808ce15480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88808ce15500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ce15580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================