======================================
| [   16.186326][   T66] ------------[ cut here ]------------
| [   16.186800][   T66] RTNL: assertion failed at net/core/link_watch.c (59)
| [ 16.187084][ T66] WARNING: CPU: 1 PID: 66 at net/core/link_watch.c:59 default_operstate (net/core/link_watch.c:59 (discriminator 3))
| [   16.187704][   T66] Modules linked in: veth
[   16.188309][   T66] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   16.188544][   T66] Workqueue: netns cleanup_net
[ 16.188795][ T66] RIP: 0010:default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 16.189043][ T66] 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 b7 9f 48 c7 c7 a0 11 b7 9f 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 b7 9f 	mov    $0xffffffff9fb71160,%rsi
  1d:	48 c7 c7 a0 11 b7 9f 	mov    $0xffffffff9fb711a0,%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
[   16.189819][   T66] RSP: 0018:ffffc90000477a48 EFLAGS: 00010282
[   16.190077][   T66] RAX: 0000000000000000 RBX: ffff88800c4b1000 RCX: 1ffffffff407b58c
[   16.190414][   T66] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[   16.190714][   T66] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff407b58c
[   16.191073][   T66] R10: 0000000000000003 R11: ffff888008d345c0 R12: 0000000000000000
[   16.191386][   T66] R13: dffffc0000000000 R14: ffff88800c4a4000 R15: ffff88800c4b1598
[   16.191670][   T66] FS:  0000000000000000(0000) GS:ffff888036080000(0000) knlGS:0000000000000000
[   16.192025][   T66] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   16.192286][   T66] CR2: 00007f93ac2c1258 CR3: 0000000032f26002 CR4: 0000000000772ef0
[   16.192549][   T66] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   16.192956][   T66] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   16.193200][   T66] PKRU: 55555554
[   16.193351][   T66] Call Trace:
[   16.193486][   T66]  <TASK>
[ 16.193576][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 16.193772][ T66] ? __warn (kernel/panic.c:748)
[ 16.193945][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 16.194130][ T66] ? report_bug (lib/bug.c:201 lib/bug.c:219)
[ 16.194364][ T66] ? handle_bug (arch/x86/kernel/traps.c:285)
[ 16.194504][ T66] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))
[ 16.194691][ T66] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)
[ 16.194932][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 16.195114][ T66] ? default_operstate (net/core/link_watch.c:59 (discriminator 3))
[ 16.195320][ T66] rfc2863_policy (net/core/link_watch.c:78)
[ 16.195508][ T66] linkwatch_do_dev (net/core/link_watch.c:180)
[ 16.195697][ T66] netdev_run_todo (net/core/dev.c:10894 (discriminator 2))
[ 16.195919][ T66] ? __pfx_netdev_run_todo (net/core/dev.c:10867)
[ 16.196097][ T66] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11455)
[ 16.196384][ T66] default_device_exit_batch (net/core/dev.c:12051)
[ 16.196574][ T66] ? __pfx_default_device_exit_batch (net/core/dev.c:12051)
[ 16.196793][ T66] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3189 kernel/locking/mutex.h:47 kernel/locking/mutex.c:66)
[ 16.196973][ T66] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:585 net/ipv4/nexthop.c:2158 net/ipv4/nexthop.c:2666 net/ipv4/nexthop.c:4010)
[ 16.197216][ T66] cleanup_net (net/core/net_namespace.c:647 (discriminator 3))
[ 16.197426][ T66] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 16.197595][ T66] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 16.197780][ T66] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 16.197971][ T66] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 16.198132][ T66] ? process_one_work (kernel/workqueue.c:3205)
[ 16.198341][ T66] process_one_work (kernel/workqueue.c:3229)
[ 16.198539][ T66] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 16.198731][ T66] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 16.198936][ T66] ? assign_work (kernel/workqueue.c:1200)
[ 16.199148][ T66] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 16.199341][ T66] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 16.199558][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 16.199727][ T66] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 16.199931][ T66] kthread (kernel/kthread.c:389)
[ 16.200071][ T66] ? __pfx_kthread (kernel/kthread.c:342)
[ 16.200267][ T66] ret_from_fork (arch/x86/kernel/process.c:147)
[ 16.200460][ T66] ? __pfx_kthread (kernel/kthread.c:342)


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