======================================
| [ 1288.308495] br0: port 1(vxlan0) entered disabled state
| [ 1288.329385] ------------[ cut here ]------------
| [ 1288.329935] WARNING: CPU: 2 PID: 11 at net/core/dev.c:11120 unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
| [ 1288.330881] Modules linked in: l2tp_ip6 l2tp_eth l2tp_ip l2tp_netlink l2tp_core xfrm_interface sha1_generic xfrm_user nft_compat nf_tables libcrc32c vxlan ip6_udp_tunnel udp_tunnel mpls_iptunnel mpls_router [last unloaded: test_bpf]
[ 1288.333580] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1288.334659] Workqueue: netns cleanup_net
[ 1288.335035] RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 1288.335356] Code: 05 31 4a 09 01 01 90 ba 32 1b 00 00 48 c7 c6 09 ec 8e a8 48 c7 c7 00 3a 92 a8 e8 2f 9a 55 ff 90 0f 0b 90 90 e9 15 fc ff ff 90 <0f> 0b 90 e9 23 fc ff ff e8 17 35 2e 00 0f 1f 80 00 00 00 00 90 90
All code
========
   0:	05 31 4a 09 01       	add    $0x1094a31,%eax
   5:	01 90 ba 32 1b 00    	add    %edx,0x1b32ba(%rax)
   b:	00 48 c7             	add    %cl,-0x39(%rax)
   e:	c6                   	(bad)
   f:	09 ec                	or     %ebp,%esp
  11:	8e a8 48 c7 c7 00    	mov    0xc7c748(%rax),%gs
  17:	3a 92 a8 e8 2f 9a    	cmp    -0x65d01758(%rdx),%dl
  1d:	55                   	push   %rbp
  1e:	ff 90 0f 0b 90 90    	call   *-0x6f6ff4f1(%rax)
  24:	e9 15 fc ff ff       	jmp    0xfffffffffffffc3e
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	e9 23 fc ff ff       	jmp    0xfffffffffffffc55
  32:	e8 17 35 2e 00       	call   0x2e354e
  37:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	e9 23 fc ff ff       	jmp    0xfffffffffffffc2b
   8:	e8 17 35 2e 00       	call   0x2e3524
   d:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  14:	90                   	nop
  15:	90                   	nop
[ 1288.336393] RSP: 0018:ffffad1b00063d78 EFLAGS: 00010287
[ 1288.336716] RAX: ffff8a27858d01c0 RBX: ffffad1b00063e08 RCX: 0000000000000000
[ 1288.337183] RDX: ffff8a27812a5a98 RSI: 0000000000000000 RDI: ffffffffa8e4aa80
[ 1288.337842] RBP: ffff8a27858d0000 R08: 0000000000000001 R09: 0000000000000001
[ 1288.338313] R10: 0000000000000004 R11: 0000000000000001 R12: ffff8a27829c6d00
[ 1288.338939] R13: ffff8a2783709900 R14: dead000000000100 R15: ffff8a2783709900
[ 1288.339592] FS:  0000000000000000(0000) GS:ffff8a27bb700000(0000) knlGS:0000000000000000
[ 1288.340318] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1288.340965] CR2: 00007fce24a3aa30 CR3: 000000003e460006 CR4: 0000000000770ef0
[ 1288.341811] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1288.342711] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1288.343551] PKRU: 55555554
[ 1288.343818] Call Trace:
[ 1288.344048]  <TASK>
[ 1288.344264] ? __warn (kernel/panic.c:677) 
[ 1288.344581] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 1288.345135] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[ 1288.345504] ? handle_bug (arch/x86/kernel/traps.c:238) 
[ 1288.345858] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[ 1288.346190] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[ 1288.346561] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 1288.347085] ? unregister_netdevice_many_notify (net/core/dev.c:6962 net/core/dev.c:11120) 
[ 1288.347610] cleanup_net (net/core/net_namespace.c:633) 
[ 1288.347896] ? process_one_work (kernel/workqueue.c:2606) 
[ 1288.348304] process_one_work (kernel/workqueue.c:2633) 
[ 1288.348638] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 1288.349005] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 1288.349373] kthread (kernel/kthread.c:388) 
[ 1288.349685] ? __pfx_kthread (kernel/kthread.c:341) 
[ 1288.349886] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 1288.350078] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
unregister_netdevice_many_notify:cleanup_net:process_one_work:worker_thread