======================================
| xx__-> [   13.950491][   T66] ------------[ cut here ]------------
| [   13.950763][   T66] RTNL: assertion failed at net/core/link_watch.c (59)
| [ 13.950985][ T66] WARNING: CPU: 0 PID: 66 at net/core/link_watch.c:59 default_operstate (net/core/link_watch.c:59 (discriminator 3))
| [   13.951370][   T66] Modules linked in:
[   13.951767][   T66] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.951964][   T66] Workqueue: netns cleanup_net
[ 13.952146][ T66] RIP: 0010:default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 13.952316][ T66] Code: 83 e4 01 0f 85 03 ff ff ff c6 05 08 23 5c 02 01 90 ba 3b 00 00 00 48 c7 c6 00 7c 97 b0 48 c7 c7 40 7c 97 b0 e8 b3 b2 e5 fd 90 <0f> 0b 90 90 e9 d9 fe ff ff 48 89 ef e8 81 63 6d 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 08 23 5c 02 01 	movb   $0x1,0x25c2308(%rip)        # 0x25c2318
  10:	90                   	nop
  11:	ba 3b 00 00 00       	mov    $0x3b,%edx
  16:	48 c7 c6 00 7c 97 b0 	mov    $0xffffffffb0977c00,%rsi
  1d:	48 c7 c7 40 7c 97 b0 	mov    $0xffffffffb0977c40,%rdi
  24:	e8 b3 b2 e5 fd       	call   0xfffffffffde5b2dc
  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 81 63 6d fe       	call   0xfffffffffe6d63bc
  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 81 63 6d fe       	call   0xfffffffffe6d6392
  11:	e9 f7 fd ff ff       	jmp    0xfffffffffffffe0d
[   13.952844][   T66] RSP: 0018:ffffc90000477a48 EFLAGS: 00010282
[   13.953039][   T66] RAX: 0000000000000000 RBX: ffff8880085f9000 RCX: 1ffffffff623dd8c
[   13.953278][   T66] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[   13.953502][   T66] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff623dd8c
[   13.953728][   T66] R10: 0000000000000003 R11: ffff888008bac5c0 R12: 0000000000000000
[   13.953956][   T66] R13: dffffc0000000000 R14: ffff8880087b1000 R15: ffff8880085f95c0
[   13.954193][   T66] FS:  0000000000000000(0000) GS:ffff88806d000000(0000) knlGS:0000000000000000
[   13.954451][   T66] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   13.954644][   T66] CR2: 0000562a9f474dec CR3: 000000000a760002 CR4: 0000000000772ef0
[   13.954878][   T66] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   13.955104][   T66] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   13.955344][   T66] PKRU: 55555554
[   13.955467][   T66] Call Trace:
[   13.955586][   T66]  <TASK>
[ 13.955670][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 13.955829][ T66] ? __warn (kernel/panic.c:748)
[ 13.955953][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 13.956108][ T66] ? report_bug (lib/bug.c:201 lib/bug.c:219)
[ 13.956278][ T66] ? handle_bug (arch/x86/kernel/traps.c:285)
[ 13.956397][ T66] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))
[ 13.956551][ T66] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)
[ 13.956717][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 13.956878][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 13.957034][ T66] rfc2863_policy (net/core/link_watch.c:78)
[ 13.957207][ T66] linkwatch_do_dev (net/core/link_watch.c:180)
[ 13.957358][ T66] netdev_run_todo (net/core/dev.c:10894 (discriminator 2))
[ 13.957513][ T66] ? __pfx_netdev_run_todo (net/core/dev.c:10867)
[ 13.957668][ T66] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11455)
[ 13.957866][ T66] default_device_exit_batch (net/core/dev.c:12051)
[ 13.958025][ T66] ? __pfx_default_device_exit_batch (net/core/dev.c:12051)
[ 13.958233][ T66] ? ops_exit_list (net/core/net_namespace.c:171 (discriminator 3))
[ 13.958393][ T66] cleanup_net (net/core/net_namespace.c:647 (discriminator 3))
[ 13.958547][ T66] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 13.958703][ T66] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 13.958853][ T66] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 13.959015][ T66] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 13.959182][ T66] ? process_one_work (kernel/workqueue.c:3205)
[ 13.959340][ T66] process_one_work (kernel/workqueue.c:3229)
[ 13.959507][ T66] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 13.959664][ T66] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 13.959835][ T66] ? assign_work (kernel/workqueue.c:1200)
[ 13.959994][ T66] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 13.960166][ T66] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 13.960362][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 13.960516][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 13.960672][ T66] kthread (kernel/kthread.c:389)
[ 13.960790][ T66] ? __pfx_kthread (kernel/kthread.c:342)
[ 13.960945][ T66] ret_from_fork (arch/x86/kernel/process.c:147)
[ 13.961096][ T66] ? __pfx_kthread (kernel/kthread.c:342)


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