======================================
| xx__-> [   12.739773][   T65] ------------[ cut here ]------------
| [   12.740275][   T65] RTNL: assertion failed at net/core/link_watch.c (59)
| [ 12.740549][ T65] WARNING: CPU: 0 PID: 65 at net/core/link_watch.c:59 default_operstate (net/core/link_watch.c:59 (discriminator 3))
| [   12.741262][   T65] Modules linked in: veth
[   12.741751][   T65] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.741974][   T65] Workqueue: netns cleanup_net
[ 12.742180][ T65] RIP: 0010:default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 12.742385][ T65] Code: 83 e4 01 0f 85 03 ff ff ff c6 05 17 5d 39 02 01 90 ba 3b 00 00 00 48 c7 c6 60 11 57 bc 48 c7 c7 a0 11 57 bc e8 43 00 eb fd 90 <0f> 0b 90 90 e9 d9 fe ff ff 48 89 ef e8 21 27 72 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 17 5d 39 02 01 	movb   $0x1,0x2395d17(%rip)        # 0x2395d27
  10:	90                   	nop
  11:	ba 3b 00 00 00       	mov    $0x3b,%edx
  16:	48 c7 c6 60 11 57 bc 	mov    $0xffffffffbc571160,%rsi
  1d:	48 c7 c7 a0 11 57 bc 	mov    $0xffffffffbc5711a0,%rdi
  24:	e8 43 00 eb fd       	call   0xfffffffffdeb006c
  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 21 27 72 fe       	call   0xfffffffffe72275c
  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 21 27 72 fe       	call   0xfffffffffe722732
  11:	e9 f7 fd ff ff       	jmp    0xfffffffffffffe0d
[   12.742995][   T65] RSP: 0018:ffffc90000467a48 EFLAGS: 00010282
[   12.743333][   T65] RAX: 0000000000000000 RBX: ffff888002424000 RCX: 1ffffffff79bb58c
[   12.743731][   T65] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[   12.744174][   T65] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff79bb58c
[   12.744587][   T65] R10: 0000000000000003 R11: ffff888008ea2300 R12: 0000000000000000
[   12.744986][   T65] R13: dffffc0000000000 R14: ffff888002421000 R15: ffff888002424598
[   12.745406][   T65] FS:  0000000000000000(0000) GS:ffff888036000000(0000) knlGS:0000000000000000
[   12.745861][   T65] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   12.746939][   T65] CR2: 00007f2a96cb8258 CR3: 0000000023926004 CR4: 0000000000772ef0
[   12.747348][   T65] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   12.747735][   T65] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   12.748099][   T65] PKRU: 55555554
[   12.748336][   T65] Call Trace:
[   12.748542][   T65]  <TASK>
[ 12.748684][ T65] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 12.748967][ T65] ? __warn (kernel/panic.c:748)
[ 12.749168][ T65] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 12.749467][ T65] ? report_bug (lib/bug.c:201 lib/bug.c:219)
[ 12.749745][ T65] ? handle_bug (arch/x86/kernel/traps.c:285)
[ 12.749949][ T65] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))
[ 12.750239][ T65] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)
[ 12.750530][ T65] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 12.750804][ T65] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 12.751072][ T65] rfc2863_policy (net/core/link_watch.c:78)
[ 12.751366][ T65] linkwatch_do_dev (net/core/link_watch.c:180)
[ 12.751631][ T65] netdev_run_todo (net/core/dev.c:10894 (discriminator 2))
[ 12.751897][ T65] ? __pfx_netdev_run_todo (net/core/dev.c:10867)
[ 12.752153][ T65] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11455)
[ 12.752497][ T65] default_device_exit_batch (net/core/dev.c:12051)
[ 12.752744][ T65] ? __pfx_default_device_exit_batch (net/core/dev.c:12051)
[ 12.753102][ T65] cleanup_net (net/core/net_namespace.c:647 (discriminator 3))
[ 12.753422][ T65] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 12.753705][ T65] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 12.753965][ T65] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 12.754269][ T65] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 12.754522][ T65] ? process_one_work (kernel/workqueue.c:3205)
[ 12.754702][ T65] process_one_work (kernel/workqueue.c:3229)
[ 12.754881][ T65] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 12.755061][ T65] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 12.755263][ T65] ? assign_work (kernel/workqueue.c:1200)
[ 12.755439][ T65] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 12.755601][ T65] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 12.755814][ T65] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 12.755975][ T65] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 12.756189][ T65] kthread (kernel/kthread.c:389)
[ 12.756436][ T65] ? __pfx_kthread (kernel/kthread.c:342)
[ 12.756716][ T65] ret_from_fork (arch/x86/kernel/process.c:147)
[ 12.756890][ T65] ? __pfx_kthread (kernel/kthread.c:342)


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