======================================
| [  301.891409][   T66] ------------[ cut here ]------------
| [  301.891797][   T66] RTNL: assertion failed at net/core/link_watch.c (59)
| [ 301.892034][ T66] WARNING: CPU: 2 PID: 66 at net/core/link_watch.c:59 default_operstate (net/core/link_watch.c:59 (discriminator 3))
| [  301.892318][   T66] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel 8021q act_mirred cls_flower bridge stp llc ip6_gre ip6_tunnel tunnel6 act_gact cls_matchall ip_gre gre sch_ingress vrf veth
[  301.893183][   T66] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  301.893403][   T66] Workqueue: netns cleanup_net
[ 301.893581][ T66] RIP: 0010:default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 301.893789][ T66] Code: 83 e4 01 0f 85 03 ff ff ff c6 05 2e 39 3a 02 01 90 ba 3b 00 00 00 48 c7 c6 00 2b 97 b3 48 c7 c7 40 2b 97 b3 e8 13 95 ea fd 90 <0f> 0b 90 90 e9 d9 fe ff ff 48 89 ef e8 d1 bb 71 fe e9 f7 fd ff ff
All code
========
   0:	83 e4 01             	and    $0x1,%esp
   3:	0f 85 03 ff ff ff    	jne    0xffffffffffffff0c
   9:	c6 05 2e 39 3a 02 01 	movb   $0x1,0x23a392e(%rip)        # 0x23a393e
  10:	90                   	nop
  11:	ba 3b 00 00 00       	mov    $0x3b,%edx
  16:	48 c7 c6 00 2b 97 b3 	mov    $0xffffffffb3972b00,%rsi
  1d:	48 c7 c7 40 2b 97 b3 	mov    $0xffffffffb3972b40,%rdi
  24:	e8 13 95 ea fd       	call   0xfffffffffdea953c
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	e9 d9 fe ff ff       	jmp    0xffffffffffffff0c
  33:	48 89 ef             	mov    %rbp,%rdi
  36:	e8 d1 bb 71 fe       	call   0xfffffffffe71bc0c
  3b:	e9 f7 fd ff ff       	jmp    0xfffffffffffffe37

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	e9 d9 fe ff ff       	jmp    0xfffffffffffffee2
   9:	48 89 ef             	mov    %rbp,%rdi
   c:	e8 d1 bb 71 fe       	call   0xfffffffffe71bbe2
  11:	e9 f7 fd ff ff       	jmp    0xfffffffffffffe0d
[  301.894601][   T66] RSP: 0018:ffffc90000477a48 EFLAGS: 00010282
[  301.895023][   T66] RAX: 0000000000000000 RBX: ffff88800f1f9000 RCX: 1ffffffff683b58c
[  301.895477][   T66] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[  301.895930][   T66] RBP: 0000000000000009 R08: 0000000000000000 R09: fffffbfff683b58c
[  301.896321][   T66] R10: 0000000000000003 R11: ffff8880053bc5c0 R12: 0000000000000000
[  301.896729][   T66] R13: dffffc0000000000 R14: ffff88800ee19000 R15: ffff88800f1f95b0
[  301.897111][   T66] FS:  0000000000000000(0000) GS:ffff888036100000(0000) knlGS:0000000000000000
[  301.897900][   T66] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  301.898233][   T66] CR2: 00007fb90d706840 CR3: 0000000010b64001 CR4: 0000000000772ef0
[  301.898625][   T66] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  301.899039][   T66] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  301.899412][   T66] PKRU: 55555554
[  301.899590][   T66] Call Trace:
[  301.899737][   T66]  <TASK>
[ 301.899837][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 301.900010][ T66] ? __warn (kernel/panic.c:748)
[ 301.900143][ T66] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141)
[ 301.900315][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 301.900498][ T66] ? report_bug (lib/bug.c:201 lib/bug.c:219)
[ 301.900673][ T66] ? handle_bug (arch/x86/kernel/traps.c:285)
[ 301.900824][ T66] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))
[ 301.901002][ T66] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)
[ 301.901179][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 301.901353][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 301.901518][ T66] rfc2863_policy (net/core/link_watch.c:78)
[ 301.901688][ T66] linkwatch_do_dev (net/core/link_watch.c:180)
[ 301.901868][ T66] netdev_run_todo (net/core/dev.c:10894 (discriminator 2))
[ 301.902036][ T66] ? __pfx_netdev_run_todo (net/core/dev.c:10867)
[ 301.902202][ T66] ? vrf_dellink (drivers/net/vrf.c:1668) vrf
[ 301.902390][ T66] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11455)
[ 301.902601][ T66] default_device_exit_batch (net/core/dev.c:12051)
[ 301.902776][ T66] ? __pfx_default_device_exit_batch (net/core/dev.c:12051)
[ 301.902988][ T66] cleanup_net (net/core/net_namespace.c:647 (discriminator 3))
[ 301.903161][ T66] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 301.903334][ T66] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 301.903505][ T66] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 301.903691][ T66] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 301.903867][ T66] ? process_one_work (kernel/workqueue.c:3205)
[ 301.904044][ T66] process_one_work (kernel/workqueue.c:3229)
[ 301.904226][ T66] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 301.904398][ T66] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 301.904570][ T66] ? assign_work (kernel/workqueue.c:1200)
[ 301.904755][ T66] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 301.904970][ T66] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 301.905175][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 301.905349][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 301.905520][ T66] kthread (kernel/kthread.c:389)
[ 301.905652][ T66] ? __pfx_kthread (kernel/kthread.c:342)
[ 301.905837][ T66] ret_from_fork (arch/x86/kernel/process.c:147)
[ 301.906004][ T66] ? __pfx_kthread (kernel/kthread.c:342)


Finger prints:
default_operstate:rfc2863_policy:linkwatch_do_dev:netdev_run_todo:default_device_exit_batch