======================================
| [  443.493189][   T72] br2: port 1(vethhv-21) entered disabled state
| [  443.546055][   T72] ------------[ cut here ]------------
| [ 443.547105][ T72] WARNING: CPU: 0 PID: 72 at net/core/dev.c:11120 unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
| [  443.547781][   T72] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel xt_mark nft_compat nf_tables libcrc32c sch_ingress act_mirred cls_basic sch_fq_codel
[  443.549094][   T72] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  443.549823][   T72] Workqueue: netns cleanup_net
[ 443.550080][ T72] RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.550549][ T72] Code: 05 44 68 61 02 01 90 ba 32 1b 00 00 48 c7 c6 e0 99 73 9e 48 c7 c7 40 9b 73 9e e8 ff 74 08 fe 90 0f 0b 90 90 e9 8a fb ff ff 90 <0f> 0b 90 e9 aa fb ff ff e8 07 78 27 fe e9 37 fc ff ff 90 0f 0b 0f
All code
========
   0:	05 44 68 61 02       	add    $0x2616844,%eax
   5:	01 90 ba 32 1b 00    	add    %edx,0x1b32ba(%rax)
   b:	00 48 c7             	add    %cl,-0x39(%rax)
   e:	c6                   	(bad)
   f:	e0 99                	loopne 0xffffffffffffffaa
  11:	73 9e                	jae    0xffffffffffffffb1
  13:	48 c7 c7 40 9b 73 9e 	mov    $0xffffffff9e739b40,%rdi
  1a:	e8 ff 74 08 fe       	call   0xfffffffffe08751e
  1f:	90                   	nop
  20:	0f 0b                	ud2
  22:	90                   	nop
  23:	90                   	nop
  24:	e9 8a fb ff ff       	jmp    0xfffffffffffffbb3
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	e9 aa fb ff ff       	jmp    0xfffffffffffffbdc
  32:	e8 07 78 27 fe       	call   0xfffffffffe27783e
  37:	e9 37 fc ff ff       	jmp    0xfffffffffffffc73
  3c:	90                   	nop
  3d:	0f 0b                	ud2
  3f:	0f                   	.byte 0xf

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	e9 aa fb ff ff       	jmp    0xfffffffffffffbb2
   8:	e8 07 78 27 fe       	call   0xfffffffffe277814
   d:	e9 37 fc ff ff       	jmp    0xfffffffffffffc49
  12:	90                   	nop
  13:	0f 0b                	ud2
  15:	0f                   	.byte 0xf
[  443.551772][   T72] RSP: 0018:ffffc9000052fb28 EFLAGS: 00010212
[  443.552226][   T72] RAX: ffff888002f5c918 RBX: ffff88800a220000 RCX: ffffffff9b6c7967
[  443.552790][   T72] RDX: 1ffffffff3f2ff0c RSI: 0000000000000008 RDI: ffffffff9f97f860
[  443.553352][   T72] RBP: ffff88800a2201c0 R08: 0000000000000000 R09: fffffbfff3f2ff0c
[  443.553884][   T72] R10: ffffffff9f97f867 R11: ffffc9000052f621 R12: ffff888003604f40
[  443.554416][   T72] R13: ffffc9000052fc00 R14: dffffc0000000000 R15: ffff888003604f40
[  443.554940][   T72] FS:  0000000000000000(0000) GS:ffff888035200000(0000) knlGS:0000000000000000
[  443.555477][   T72] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  443.555953][   T72] CR2: 00007ffc1d585758 CR3: 00000000077dc003 CR4: 0000000000770ef0
[  443.556429][   T72] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  443.556896][   T72] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  443.557362][   T72] PKRU: 55555554
[  443.557560][   T72] Call Trace:
[  443.557773][   T72]  <TASK>
[ 443.557937][ T72] ? __warn (kernel/panic.c:677) 
[ 443.558203][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.558622][ T72] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[ 443.558873][ T72] ? handle_bug (arch/x86/kernel/traps.c:238) 
[ 443.559144][ T72] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[ 443.559410][ T72] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[ 443.559783][ T72] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 443.560051][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.560478][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:6962 net/core/dev.c:11120) 
[ 443.560880][ T72] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 443.561268][ T72] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 443.561535][ T72] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:569 net/ipv4/nexthop.c:1918 net/ipv4/nexthop.c:2426 net/ipv4/nexthop.c:3754) 
[ 443.561891][ T72] cleanup_net (net/core/net_namespace.c:633) 
[ 443.562129][ T72] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 443.562489][ T72] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 443.562766][ T72] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 443.563049][ T72] ? process_one_work (kernel/workqueue.c:2609) 
[ 443.563369][ T72] process_one_work (kernel/workqueue.c:2633) 
[ 443.563731][ T72] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) 
[ 443.563973][ T72] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 443.564332][ T72] ? assign_work (kernel/workqueue.c:1101) 
[ 443.564597][ T72] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 443.564895][ T72] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 443.565277][ T72] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 443.565575][ T72] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 443.565902][ T72] kthread (kernel/kthread.c:388) 
[ 443.566136][ T72] ? __pfx_kthread (kernel/kthread.c:341) 
[ 443.566452][ T72] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 443.566722][ T72] ? __pfx_kthread (kernel/kthread.c:341) 
[ 443.567030][ T72] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  443.570109][   T72] ---[ end trace 0000000000000000 ]---
| [  443.573521][   T72] ------------[ cut here ]------------
| [ 443.573838][ T72] WARNING: CPU: 2 PID: 72 at net/core/dev.c:11120 unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
| [  443.574384][   T72] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel xt_mark nft_compat nf_tables libcrc32c sch_ingress act_mirred cls_basic sch_fq_codel
[  443.575885][   T72] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  443.576513][   T72] Workqueue: netns cleanup_net
[ 443.576769][ T72] RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.577134][ T72] Code: 05 44 68 61 02 01 90 ba 32 1b 00 00 48 c7 c6 e0 99 73 9e 48 c7 c7 40 9b 73 9e e8 ff 74 08 fe 90 0f 0b 90 90 e9 8a fb ff ff 90 <0f> 0b 90 e9 aa fb ff ff e8 07 78 27 fe e9 37 fc ff ff 90 0f 0b 0f
All code
========
   0:	05 44 68 61 02       	add    $0x2616844,%eax
   5:	01 90 ba 32 1b 00    	add    %edx,0x1b32ba(%rax)
   b:	00 48 c7             	add    %cl,-0x39(%rax)
   e:	c6                   	(bad)
   f:	e0 99                	loopne 0xffffffffffffffaa
  11:	73 9e                	jae    0xffffffffffffffb1
  13:	48 c7 c7 40 9b 73 9e 	mov    $0xffffffff9e739b40,%rdi
  1a:	e8 ff 74 08 fe       	call   0xfffffffffe08751e
  1f:	90                   	nop
  20:	0f 0b                	ud2
  22:	90                   	nop
  23:	90                   	nop
  24:	e9 8a fb ff ff       	jmp    0xfffffffffffffbb3
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	e9 aa fb ff ff       	jmp    0xfffffffffffffbdc
  32:	e8 07 78 27 fe       	call   0xfffffffffe27783e
  37:	e9 37 fc ff ff       	jmp    0xfffffffffffffc73
  3c:	90                   	nop
  3d:	0f 0b                	ud2
  3f:	0f                   	.byte 0xf

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	e9 aa fb ff ff       	jmp    0xfffffffffffffbb2
   8:	e8 07 78 27 fe       	call   0xfffffffffe277814
   d:	e9 37 fc ff ff       	jmp    0xfffffffffffffc49
  12:	90                   	nop
  13:	0f 0b                	ud2
  15:	0f                   	.byte 0xf
[  443.578122][   T72] RSP: 0018:ffffc9000052fb28 EFLAGS: 00010293
[  443.578446][   T72] RAX: ffff88800832c918 RBX: ffff888006538000 RCX: ffffffff9b6c7967
[  443.578854][   T72] RDX: 1ffffffff3f2ff0c RSI: 0000000000000008 RDI: ffffffff9f97f860
[  443.579257][   T72] RBP: ffff8880065381c0 R08: 0000000000000000 R09: fffffbfff3f2ff0c
[  443.579719][   T72] R10: ffffffff9f97f867 R11: ffffc9000052f621 R12: ffff88800832d6c0
[  443.580180][   T72] R13: ffffc9000052fc00 R14: dffffc0000000000 R15: ffff88800832d6c0
[  443.580628][   T72] FS:  0000000000000000(0000) GS:ffff888035a00000(0000) knlGS:0000000000000000
[  443.581139][   T72] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  443.581532][   T72] CR2: 00007f4b6858d000 CR3: 000000002b334004 CR4: 0000000000770ef0
[  443.581969][   T72] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  443.582411][   T72] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  443.582829][   T72] PKRU: 55555554
[  443.583048][   T72] Call Trace:
[  443.583247][   T72]  <TASK>
[ 443.583420][ T72] ? __warn (kernel/panic.c:677) 
[ 443.583665][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.584015][ T72] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[ 443.584295][ T72] ? handle_bug (arch/x86/kernel/traps.c:238) 
[ 443.584525][ T72] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[ 443.584873][ T72] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[ 443.585178][ T72] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 443.585443][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:11120 (discriminator 1)) 
[ 443.585813][ T72] ? unregister_netdevice_many_notify (net/core/dev.c:6962 net/core/dev.c:11120) 
[ 443.586187][ T72] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 443.586573][ T72] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 443.586884][ T72] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:569 net/ipv4/nexthop.c:1918 net/ipv4/nexthop.c:2426 net/ipv4/nexthop.c:3754) 
[ 443.587226][ T72] cleanup_net (net/core/net_namespace.c:633) 
[ 443.587475][ T72] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 443.587766][ T72] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 443.588031][ T72] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 443.588276][ T72] ? process_one_work (kernel/workqueue.c:2609) 
[ 443.588562][ T72] process_one_work (kernel/workqueue.c:2633) 
[ 443.588830][ T72] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) 
[ 443.589070][ T72] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 443.589372][ T72] ? assign_work (kernel/workqueue.c:1101) 
[ 443.589621][ T72] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 443.589868][ T72] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 443.590214][ T72] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 443.590492][ T72] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 443.590758][ T72] kthread (kernel/kthread.c:388) 
[ 443.590975][ T72] ? __pfx_kthread (kernel/kthread.c:341) 
[ 443.591260][ T72] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 443.591538][ T72] ? __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