======================================
| [  794.254962] br2: port 1(vethhv-21) entered disabled state
| [  794.290089] ------------[ cut here ]------------
| [  794.290385] WARNING: CPU: 0 PID: 67 at net/core/dev.c:11120 unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
| [  794.290913] Modules linked in: bonding psample macsec fou ip6_gre ip_gre gre cls_u32 sch_htb poly1305_generic libpoly1305 chacha_generic libchacha chacha20poly1305 tls act_gact cls_flower vxlan ip6_udp_tunnel udp_tunnel xt_mark sch_ingress act_mirred cls_basic sch_fq_codel sha1_generic xfrm_user xt_policy nft_compat nf_tables libcrc32c [last unloaded: netdevsim]
[  794.293052] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  794.293712] Workqueue: netns cleanup_net
[  794.293931] RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 794.294263] Code: 05 31 4a 09 01 01 90 ba 32 1b 00 00 48 c7 c6 09 ec 0e be 48 c7 c7 00 3a 12 be 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:	0e                   	(bad)
  12:	be 48 c7 c7 00       	mov    $0xc7c748,%esi
  17:	3a 12                	cmp    (%rdx),%dl
  19:	be e8 2f 9a 55       	mov    $0x559a2fe8,%esi
  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
[  794.295342] RSP: 0018:ffffa4e28025bd78 EFLAGS: 00010287
[  794.295729] RAX: ffff911a85ab01c0 RBX: ffffa4e28025be08 RCX: 0000000000000000
[  794.296166] RDX: ffff911a82b52198 RSI: 0000000000000000 RDI: ffffffffbe64aa80
[  794.296598] RBP: ffff911a85ab0000 R08: 0000000000000001 R09: 0000000000000001
[  794.297059] R10: 0000000000000004 R11: 0000000000000001 R12: ffff911a828aaa00
[  794.297499] R13: ffff911a82b52880 R14: dead000000000100 R15: ffff911a82b52880
[  794.297945] FS:  0000000000000000(0000) GS:ffff911abec00000(0000) knlGS:0000000000000000
[  794.298418] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  794.298759] CR2: 00007f7ad1da5c08 CR3: 0000000037460001 CR4: 0000000000770ef0
[  794.299212] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  794.299645] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  794.300086] PKRU: 55555554
[  794.300283] Call Trace:
[  794.300441]  <TASK>
[  794.300604] ? __warn (kernel/panic.c:677) 
[  794.300829] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[  794.301165] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  794.301399] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  794.301680] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  794.301969] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  794.302272] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[  794.302662] ? unregister_netdevice_many_notify (net/core/dev.c:6962 net/core/dev.c:11120) 
[  794.302993] cleanup_net (net/core/net_namespace.c:633) 
[  794.303265] ? process_one_work (kernel/workqueue.c:2606) 
[  794.303563] process_one_work (kernel/workqueue.c:2633) 
[  794.303837] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  794.304079] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  794.304369] kthread (kernel/kthread.c:388) 
[  794.304647] ? __pfx_kthread (kernel/kthread.c:341) 
[  794.304875] ret_from_fork (arch/x86/kernel/process.c:147) 
[  794.305102] ? __pfx_kthread (kernel/kthread.c:341) 
[  794.305369] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  794.308141] ---[ end trace 0000000000000000 ]---
| [  794.308798] ------------[ cut here ]------------
| [  794.309138] WARNING: CPU: 0 PID: 67 at net/core/dev.c:11120 unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
| [  794.309757] Modules linked in: bonding psample macsec fou ip6_gre ip_gre gre cls_u32 sch_htb poly1305_generic libpoly1305 chacha_generic libchacha chacha20poly1305 tls act_gact cls_flower vxlan ip6_udp_tunnel udp_tunnel xt_mark sch_ingress act_mirred cls_basic sch_fq_codel sha1_generic xfrm_user xt_policy nft_compat nf_tables libcrc32c [last unloaded: netdevsim]
[  794.312145] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  794.312827] Workqueue: netns cleanup_net
[  794.313105] RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 794.313505] Code: 05 31 4a 09 01 01 90 ba 32 1b 00 00 48 c7 c6 09 ec 0e be 48 c7 c7 00 3a 12 be 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:	0e                   	(bad)
  12:	be 48 c7 c7 00       	mov    $0xc7c748,%esi
  17:	3a 12                	cmp    (%rdx),%dl
  19:	be e8 2f 9a 55       	mov    $0x559a2fe8,%esi
  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
[  794.314498] RSP: 0018:ffffa4e28025bd78 EFLAGS: 00010287
[  794.314846] RAX: ffff911a84bf81c0 RBX: ffffa4e28025be08 RCX: 0000000000000000
[  794.315298] RDX: ffff911a82bf1dd8 RSI: 0000000000000000 RDI: ffffffffbe64aa80
[  794.315706] RBP: ffff911a84bf8000 R08: 0000000000000001 R09: 0000000000000001
[  794.316099] R10: 0000000000000004 R11: 0000000000000001 R12: ffff911a828aaa00
[  794.316512] R13: ffff911a82bf1e00 R14: dead000000000100 R15: ffff911a82bf1e00
[  794.316927] FS:  0000000000000000(0000) GS:ffff911abec00000(0000) knlGS:0000000000000000
[  794.317395] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  794.317714] CR2: 00007f7ad1da5c08 CR3: 0000000037460001 CR4: 0000000000770ef0
[  794.318119] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  794.318556] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  794.318965] PKRU: 55555554
[  794.319132] Call Trace:
[  794.319305]  <TASK>
[  794.319466] ? __warn (kernel/panic.c:677) 
[  794.319687] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[  794.319997] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  794.320247] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  794.320488] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  794.320746] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  794.320989] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[  794.321327] ? unregister_netdevice_many_notify (net/core/dev.c:6962 net/core/dev.c:11120) 
[  794.321682] cleanup_net (net/core/net_namespace.c:633) 
[  794.321943] ? process_one_work (kernel/workqueue.c:2606) 
[  794.322192] process_one_work (kernel/workqueue.c:2633) 
[  794.322464] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  794.322713] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  794.322983] kthread (kernel/kthread.c:388) 
[  794.323192] ? __pfx_kthread (kernel/kthread.c:341) 
[  794.323439] ret_from_fork (arch/x86/kernel/process.c:147) 
[  794.323691] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
unregister_netdevice_many_notify:cleanup_net:process_one_work:worker_thread
unregister_netdevice_many_notify:cleanup_net:process_one_work:worker_thread