======================================
| xx__-> [    9.073287][  T167] ------------[ cut here ]------------
| [    9.073691][  T167] WARNING: net/core/rtnetlink.c:4523 at rtmsg_ifinfo_build_skb+0x1a6/0x250, CPU#3: unshare/167
| [    9.074006][  T167] Modules linked in: nf_tables
| [    9.074444][  T167] Tainted: [W]=WARN
[    9.074546][  T167] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    9.074741][  T167] RIP: 0010:rtmsg_ifinfo_build_skb (net/core/rtnetlink.c:4523 (discriminator 3))
[    9.074915][  T167] Code: 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 79 48 8b 44 24 58 44 8b 48 08 e9 42 ff ff ff 90 <0f> 0b 90 ba 02 00 00 00 48 89 de 31 ff e8 88 e9 f0 ff b9 a6 ff ff
All code
========
   0:	89 fa                	mov    %edi,%edx
   2:	48 c1 ea 03          	shr    $0x3,%rdx
   6:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx
   a:	48 89 f8             	mov    %rdi,%rax
   d:	83 e0 07             	and    $0x7,%eax
  10:	83 c0 03             	add    $0x3,%eax
  13:	38 d0                	cmp    %dl,%al
  15:	7c 04                	jl     0x1b
  17:	84 d2                	test   %dl,%dl
  19:	75 79                	jne    0x94
  1b:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  20:	44 8b 48 08          	mov    0x8(%rax),%r9d
  24:	e9 42 ff ff ff       	jmp    0xffffffffffffff6b
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	ba 02 00 00 00       	mov    $0x2,%edx
  32:	48 89 de             	mov    %rbx,%rsi
  35:	31 ff                	xor    %edi,%edi
  37:	e8 88 e9 f0 ff       	call   0xfffffffffff0e9c4
  3c:	b9                   	.byte 0xb9
  3d:	a6                   	cmpsb  (%rdi),(%rsi)
  3e:	ff                   	(bad)
  3f:	ff                   	.byte 0xff

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	ba 02 00 00 00       	mov    $0x2,%edx
   8:	48 89 de             	mov    %rbx,%rsi
   b:	31 ff                	xor    %edi,%edi
   d:	e8 88 e9 f0 ff       	call   0xfffffffffff0e99a
  12:	b9                   	.byte 0xb9
  13:	a6                   	cmpsb  (%rdi),(%rsi)
  14:	ff                   	(bad)
  15:	ff                   	.byte 0xff
[    9.075392][  T167] RSP: 0018:ffa0000000517ab0 EFLAGS: 00010286
[    9.075559][  T167] RAX: 00000000ffffffa6 RBX: ff1100000ae60900 RCX: 1ff40000000a2f1c
[    9.075756][  T167] RDX: 0000000000000007 RSI: 0000000000000000 RDI: ff1100000ae609bc
[    9.075953][  T167] RBP: ff1100000872c000 R08: 1fe22000015cc139 R09: ff1100000b5f2ed0
[    9.076153][  T167] R10: 0000000000000003 R11: 0000000000000001 R12: 00000000ffffffff
[    9.076354][  T167] R13: 0000000000000000 R14: 0000000000000000 R15: ff1100000872c000
[    9.076569][  T167] FS:  00007f79e99ef740(0000) GS:ff11000082f2c000(0000) knlGS:0000000000000000
[    9.076801][  T167] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    9.076966][  T167] CR2: 0000556793053310 CR3: 000000000be87001 CR4: 0000000000771ef0
[    9.077164][  T167] PKRU: 55555554
[    9.077263][  T167] Call Trace:
[    9.077368][  T167]  <TASK>
[    9.077442][  T167]  rtmsg_ifinfo_event.part.0 (net/core/rtnetlink.c:4551)
[    9.077576][  T167]  ? notifier_call_chain (kernel/notifier.c:85)
[    9.077709][  T167]  rtmsg_ifinfo (net/core/rtnetlink.c:4551 net/core/rtnetlink.c:4560)
[    9.077807][  T167]  register_netdevice (net/core/dev.c:11488)
[    9.077940][  T167]  ? unregister_netdevice_queue (./include/linux/list.h:162)
[    9.078106][  T167]  register_netdev (net/core/dev.c:11552)
[    9.078235][  T167]  loopback_net_init (drivers/net/loopback.c:218)
[    9.078372][  T167]  ops_init (net/core/net_namespace.c:137)
[    9.078478][  T167]  setup_net (net/core/net_namespace.c:446)
[    9.078576][  T167]  ? unregister_pernet_device (net/core/net_namespace.c:1503)
[    9.078708][  T167]  ? lockdep_init_map_type (kernel/locking/lockdep.c:4973)
[    9.078843][  T167]  ? mutex_init_lockdep (./include/linux/lockdep.h:135 ./include/linux/lockdep.h:142 kernel/locking/mutex.c:185)
[    9.078977][  T167]  copy_net_ns (net/core/net_namespace.c:579)
[    9.079109][  T167]  create_new_namespaces (kernel/nsproxy.c:132)
[    9.079241][  T167]  unshare_nsproxy_namespaces (kernel/nsproxy.c:234 (discriminator 4))
[    9.079382][  T167]  ksys_unshare (kernel/fork.c:3243)
[    9.079513][  T167]  ? walk_process_tree (kernel/fork.c:3036 (discriminator 19))
[    9.079649][  T167]  __x64_sys_unshare (kernel/fork.c:3317 kernel/fork.c:3315 kernel/fork.c:3315)
[    9.079777][  T167]  ? do_syscall_64 (./include/linux/entry-common.h:177 arch/x86/entry/syscall_64.c:89)
[    9.079909][  T167]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[    9.080043][  T167]  ? trace_hardirqs_off (kernel/trace/trace_preemptirq.c:104 (discriminator 1))
[    9.080174][  T167]  ? exc_page_fault (arch/x86/mm/fault.c:1480 (discriminator 3) arch/x86/mm/fault.c:1527 (discriminator 3))
[    9.080309][  T167]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
[    9.080477][  T167] RIP: 0033:0x7f79e9aeabcb
[    9.080615][  T167] Code: 73 01 c3 48 8b 0d 2d 82 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d fd 81 0f 00 f7 d8 64 89 01 48
All code
========
   0:	73 01                	jae    0x3
   2:	c3                   	ret
   3:	48 8b 0d 2d 82 0f 00 	mov    0xf822d(%rip),%rcx        # 0xf8237
   a:	f7 d8                	neg    %eax
   c:	64 89 01             	mov    %eax,%fs:(%rcx)
   f:	48 83 c8 ff          	or     $0xffffffffffffffff,%rax
  13:	c3                   	ret
  14:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  1b:	00 00 00 
  1e:	90                   	nop
  1f:	f3 0f 1e fa          	endbr64
  23:	b8 10 01 00 00       	mov    $0x110,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax		<-- trapping instruction
  30:	73 01                	jae    0x33
  32:	c3                   	ret
  33:	48 8b 0d fd 81 0f 00 	mov    0xf81fd(%rip),%rcx        # 0xf8237
  3a:	f7 d8                	neg    %eax
  3c:	64 89 01             	mov    %eax,%fs:(%rcx)
  3f:	48                   	rex.W

Code starting with the faulting instruction
===========================================
   0:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   6:	73 01                	jae    0x9
   8:	c3                   	ret
   9:	48 8b 0d fd 81 0f 00 	mov    0xf81fd(%rip),%rcx        # 0xf820d
  10:	f7 d8                	neg    %eax
  12:	64 89 01             	mov    %eax,%fs:(%rcx)
  15:	48                   	rex.W
[    9.081083][  T167] RSP: 002b:00007fff62e37d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
[    9.081279][  T167] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f79e9aeabcb
[    9.081481][  T167] RDX: 0000000000000000 RSI: 00007fff62e37b00 RDI: 0000000040000000
[    9.081678][  T167] RBP: 00007fff62e38120 R08: 00007fff62e37cf0 R09: 0000000000000000
[    9.081878][  T167] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000040000000
[    9.082071][  T167] R13: 0000000000000000 R14: 00000000ffffffff R15: 0000556793056b68
| [   20.710896][   T70] ------------[ cut here ]------------
| [   20.711075][   T70] WARNING: net/core/rtnetlink.c:4523 at rtmsg_ifinfo_build_skb+0x1a6/0x250, CPU#0: 1/70
| [   20.711370][   T70] Modules linked in: nft_quota nf_tables
| [   20.711807][   T70] Tainted: [W]=WARN
[   20.711903][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   20.712058][   T70] Workqueue: netns cleanup_net
[   20.712233][   T70] RIP: 0010:rtmsg_ifinfo_build_skb (net/core/rtnetlink.c:4523 (discriminator 3))
[   20.712402][   T70] Code: 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 79 48 8b 44 24 58 44 8b 48 08 e9 42 ff ff ff 90 <0f> 0b 90 ba 02 00 00 00 48 89 de 31 ff e8 88 e9 f0 ff b9 a6 ff ff
All code
========
   0:	89 fa                	mov    %edi,%edx
   2:	48 c1 ea 03          	shr    $0x3,%rdx
   6:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx
   a:	48 89 f8             	mov    %rdi,%rax
   d:	83 e0 07             	and    $0x7,%eax
  10:	83 c0 03             	add    $0x3,%eax
  13:	38 d0                	cmp    %dl,%al
  15:	7c 04                	jl     0x1b
  17:	84 d2                	test   %dl,%dl
  19:	75 79                	jne    0x94
  1b:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  20:	44 8b 48 08          	mov    0x8(%rax),%r9d
  24:	e9 42 ff ff ff       	jmp    0xffffffffffffff6b
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	ba 02 00 00 00       	mov    $0x2,%edx
  32:	48 89 de             	mov    %rbx,%rsi
  35:	31 ff                	xor    %edi,%edi
  37:	e8 88 e9 f0 ff       	call   0xfffffffffff0e9c4
  3c:	b9                   	.byte 0xb9
  3d:	a6                   	cmpsb  (%rdi),(%rsi)
  3e:	ff                   	(bad)
  3f:	ff                   	.byte 0xff

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	ba 02 00 00 00       	mov    $0x2,%edx
   8:	48 89 de             	mov    %rbx,%rsi
   b:	31 ff                	xor    %edi,%edi
   d:	e8 88 e9 f0 ff       	call   0xfffffffffff0e99a
  12:	b9                   	.byte 0xb9
  13:	a6                   	cmpsb  (%rdi),(%rsi)
  14:	ff                   	(bad)
  15:	ff                   	.byte 0xff
[   20.712839][   T70] RSP: 0018:ffa00000004b7878 EFLAGS: 00010286
[   20.712992][   T70] RAX: 00000000ffffffa6 RBX: ff1100000aea8900 RCX: 1ff4000000096ed5
[   20.713175][   T70] RDX: 0000000000000007 RSI: 0000000000000000 RDI: ff1100000aea89bc
[   20.713362][   T70] RBP: ff1100000872c000 R08: 1fe22000015d5139 R09: ff11000008ce8be0
[   20.713547][   T70] R10: 0000000000000000 R11: 0000000000000001 R12: 00000000ffffffff
[   20.713729][   T70] R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
[   20.713915][   T70] FS:  0000000000000000(0000) GS:ff11000082dac000(0000) knlGS:0000000000000000
[   20.714131][   T70] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.714284][   T70] CR2: 00007f1bca7fc680 CR3: 0000000036b39002 CR4: 0000000000771ef0
[   20.714477][   T70] PKRU: 55555554
[   20.714569][   T70] Call Trace:
[   20.714659][   T70]  <TASK>
[   20.714723][   T70]  unregister_netdevice_many_notify (net/core/dev.c:12439)
[   20.714878][   T70]  ? unregister_netdevice_queued (./include/linux/list.h:404 (discriminator 3))
[   20.715032][   T70]  ? perf_trace_sched_switch (./include/linux/list.h:1021 (discriminator 3))
[   20.715158][   T70]  default_device_exit_batch (net/core/dev.c:12497 net/core/dev.c:13089)
[   20.715281][   T70]  ? generic_xdp_install (./include/linux/netdevice.h:5659)
[   20.715409][   T70]  ? ipmr_free_table (net/ipv4/ipmr.c:453)
[   20.715537][   T70]  ? unregister_netdev (./include/net/net_namespace.h:419 (discriminator 7))
[   20.715657][   T70]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   20.715779][   T70]  ? nexthop_net_exit_rtnl (./include/linux/rtnetlink.h:150 (discriminator 1) net/ipv4/nexthop.c:4145 (discriminator 1))
[   20.715902][   T70]  ops_undo_list (net/core/net_namespace.c:205 net/core/net_namespace.c:252)
[   20.716024][   T70]  ? rtnl_net_dumpid_one (net/core/net_namespace.c:1094)
[   20.716144][   T70]  ? __lock_release.isra.0 (kernel/locking/lockdep.c:5535)
[   20.716268][   T70]  cleanup_net (net/core/net_namespace.c:702)
[   20.716397][   T70]  ? net_passive_dec (./include/linux/llist.h:241)
[   20.716522][   T70]  ? process_one_work (kernel/workqueue.c:3290 (discriminator 2))
[   20.716644][   T70]  ? lock_acquire (./include/trace/events/lock.h:24 (discriminator 22) kernel/locking/lockdep.c:5831 (discriminator 22))
[   20.716766][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:752 (discriminator 3))
[   20.716892][   T70]  process_one_work (kernel/workqueue.c:3314)
[   20.717016][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:1822 (discriminator 4))
[   20.717143][   T70]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:5868 (discriminator 1))
[   20.717274][   T70]  worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
[   20.717405][   T70]  ? rescuer_thread (./include/linux/list.h:404 (discriminator 3))
[   20.717531][   T70]  ? __kthread_parkme (./include/linux/instrumented.h:82 ./include/asm-generic/bitops/instrumented-non-atomic.h:141 kernel/kthread.c:272)
[   20.717652][   T70]  ? rescuer_thread (./include/linux/list.h:404 (discriminator 3))
[   20.717773][   T70]  kthread (kernel/kthread.c:436)
[   20.717866][   T70]  ? trace_irq_enable.constprop.0 (./include/trace/events/preemptirq.h:40 (discriminator 22))
[   20.718017][   T70]  ? kthread_affine_node (kernel/kthread.c:378)
[   20.718138][   T70]  ret_from_fork (arch/x86/kernel/process.c:158)
[   20.718261][   T70]  ? arch_exit_to_user_mode_prepare.isra.0 (arch/x86/entry/syscall_64.c:37)
[   20.718423][   T70]  ? __switch_to (arch/x86/kernel/process_64.c:403 arch/x86/kernel/process_64.c:663)
[   20.718546][   T70]  ? kthread_affine_node (kernel/kthread.c:378)


Finger prints:
rtmsg_ifinfo_build_skb:rtmsg_ifinfo:register_netdevice:register_netdev:loopback_net_init
rtmsg_ifinfo_build_skb:unregister_netdevice_many_notify:default_device_exit_batch:ops_undo_list:cleanup_net