------------[ cut here ]------------
workqueue: cannot queue hci_cmd_timeout on wq hci0
WARNING: kernel/workqueue.c:2251 at __queue_work+0xc9d/0x10e0 kernel/workqueue.c:2250, CPU#2: kworker/u32:6/1140
Modules linked in:
CPU: 2 UID: 0 PID: 1140 Comm: kworker/u32:6 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:__queue_work+0xca1/0x10e0 kernel/workqueue.c:2250
Code: 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 0c 04 00 00 48 8d 3d f3 8c 07 0f 48 8b 75 18 <67> 48 0f b9 3a e9 90 f7 ff ff e8 d0 11 3a 00 90 0f 0b 90 e9 15 f6
RSP: 0018:ffffc90000538be8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: 0000000000000100 RCX: 1ffff1100cdc4951
RDX: ffff88806263d178 RSI: ffffffff8a68cae0 RDI: ffffffff908bd3d0
RBP: ffff888066e24a70 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000100 R11: ffff888027a58b30 R12: 1ffff920000a718f
R13: ffffffff81845820 R14: 0000000000000100 R15: ffff88806263d000
FS:  0000000000000000(0000) GS:ffff8880978fd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f510cc1c CR3: 000000000e184000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 call_timer_fn+0x19a/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1794 [inline]
 __run_timers+0x569/0xae0 kernel/time/timer.c:2373
 __run_timer_base kernel/time/timer.c:2385 [inline]
 __run_timer_base kernel/time/timer.c:2377 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2394
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2404
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lockdep_unregister_key+0xe9/0x140 kernel/locking/lockdep.c:6616
Code: 48 89 ef e8 89 ee ff ff 48 83 2d 59 f9 38 14 01 89 c3 e8 0a ef ff ff 9c 58 f6 c4 02 75 52 41 f7 c4 00 02 00 00 74 01 fb 84 db <75> 1b 5b 5d 41 5c e9 ec ac 0a 00 8b 05 1a 02 f0 0e 31 db 85 c0 74
RSP: 0018:ffffc90006a9f840 EFLAGS: 00000246
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dbba79d RDI: ffffffff8bf2b500
RBP: ffffffff97390b48 R08: 000000000002f885 R09: ffffffff95d7fbea
R10: 0000000000000002 R11: ffff888027a58b30 R12: 0000000000000246
R13: ffff8880624e2000 R14: ffff8880624e24c8 R15: ffff8880624e2cc9
 __qdisc_destroy+0x11a/0x4a0 net/sched/sch_generic.c:1079
 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1105
 shutdown_scheduler_queue+0xa5/0x160 net/sched/sch_generic.c:1158
 netdev_for_each_tx_queue include/linux/netdevice.h:2680 [inline]
 dev_shutdown+0xb8/0x430 net/sched/sch_generic.c:1490
 unregister_netdevice_many_notify+0xb37/0x2590 net/core/dev.c:12369
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x8fc/0xab0 net/core/net_namespace.c:248
 cleanup_net+0x41b/0x830 net/core/net_namespace.c:696
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess):
   0:	78 01                	js     0x3
   2:	00 00                	add    %al,(%rax)
   4:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
   b:	fc ff df
   e:	48 89 f9             	mov    %rdi,%rcx
  11:	48 c1 e9 03          	shr    $0x3,%rcx
  15:	80 3c 01 00          	cmpb   $0x0,(%rcx,%rax,1)
  19:	0f 85 0c 04 00 00    	jne    0x42b
  1f:	48 8d 3d f3 8c 07 0f 	lea    0xf078cf3(%rip),%rdi        # 0xf078d19
  26:	48 8b 75 18          	mov    0x18(%rbp),%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 90 f7 ff ff       	jmp    0xfffff7c4
  34:	e8 d0 11 3a 00       	call   0x3a1209
  39:	90                   	nop
  3a:	0f 0b                	ud2
  3c:	90                   	nop
  3d:	e9                   	.byte 0xe9
  3e:	15                   	.byte 0x15
  3f:	f6                   	.byte 0xf6