======================================
| [ 191.834993][ T822] #0: ffffffff9bbe7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 191.835295][ T822] #1: ffffffff9bbd6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  191.835620][  T822]
| [  191.835620][  T822] stack backtrace:
[  191.836064][  T822] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  191.836272][  T822] Call Trace:
[  191.836394][  T822]  <TASK>
[ 191.836481][ T822] dump_stack_lvl (lib/dump_stack.c:123)
[ 191.836648][ T822] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 191.836810][ T822] validate_chain (kernel/locking/lockdep.c:3894)
[ 191.836987][ T822] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 191.837151][ T822] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228)
[ 191.837324][ T822] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 191.837455][ T822] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 191.837639][ T822] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 191.837812][ T822] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 191.838022][ T822] ? netconsole_process_cleanups_core (drivers/net/netconsole.c:242 (discriminator 11))
[ 191.838237][ T822] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 191.838414][ T822] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 191.838575][ T822] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 191.838753][ T822] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 191.838952][ T822] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 191.839075][ T822] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 191.839271][ T822] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 191.839446][ T822] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 191.839605][ T822] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 191.839766][ T822] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 191.839935][ T822] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 191.840097][ T822] __netdev_upper_dev_unlink (net/core/dev.c:8000 (discriminator 11) net/core/dev.c:8017 (discriminator 11) net/core/dev.c:8167 (discriminator 11))
[ 191.840247][ T822] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 191.840358][ T822] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 191.840554][ T822] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 191.840740][ T822] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 191.840906][ T822] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 191.841107][ T822] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 191.841292][ T822] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804) vrf
[ 191.841441][ T822] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 191.841590][ T822] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 191.841771][ T822] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 191.841984][ T822] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228)
[ 191.842138][ T822] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 191.842262][ T822] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 191.842457][ T822] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 191.842641][ T822] ? kfree (mm/slub.c:4613 mm/slub.c:4761)
[ 191.842772][ T822] ? vlan_vid_del (net/8021q/vlan_core.c:368 net/8021q/vlan_core.c:387)
[ 191.842940][ T822] ? vlan_vid_del (net/8021q/vlan_core.c:368 net/8021q/vlan_core.c:387)
[ 191.843093][ T822] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 191.843264][ T822] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 191.843433][ T822] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 191.843595][ T822] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 191.843750][ T822] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 191.843903][ T822] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 191.844056][ T822] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 191.844212][ T822] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 191.844357][ T822] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 191.844509][ T822] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 191.844655][ T822] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 191.844811][ T822] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228)
[ 191.844964][ T822] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 191.845095][ T822] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 191.845244][ T822] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 191.845403][ T822] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 191.845562][ T822] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 191.845744][ T822] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 191.845906][ T822] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 ./include/net/netns/generic.h:48 net/netlink/af_netlink.c:333)
[ 191.846070][ T822] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 191.846229][ T822] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 191.846391][ T822] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 191.846555][ T822] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 191.846723][ T822] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 191.846898][ T822] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 191.847062][ T822] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 191.847232][ T822] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 191.847444][ T822] ___sys_sendmsg (net/socket.c:2650)
[ 191.847607][ T822] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 191.847776][ T822] ? kasan_save_stack (mm/kasan/common.c:49)
[ 191.847946][ T822] ? kasan_save_stack (mm/kasan/common.c:48)
[ 191.848110][ T822] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 191.848272][ T822] ? __call_rcu_common.constprop.0 (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:87 ./arch/x86/include/asm/irqflags.h:123 kernel/rcu/tree.c:3087)
[ 191.848486][ T822] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 191.848648][ T822] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 191.848809][ T822] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 191.849012][ T822] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 191.849183][ T822] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 191.849351][ T822] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 191.849513][ T822] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 191.849715][ T822] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 191.849880][ T822] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 191.850043][ T822] __sys_sendmsg (net/socket.c:2680)
[ 191.850207][ T822] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 191.850369][ T822] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 191.850598][ T822] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 191.850763][ T822] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  191.850989][  T822] RIP: 0033:0x7fbb0ff7c9a7
[ 191.851161][ T822] Code: 0a 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
All code
========
   0:	0a 00                	or     (%rax),%al
   2:	f7 d8                	neg    %eax
   4:	64 89 02             	mov    %eax,%fs:(%rdx)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b9                	jmp    0xffffffffffffffc9
  10:	0f 1f 00             	nopl   (%rax)
  13:	f3 0f 1e fa          	endbr64
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 10                	jne    0x33
  23:	b8 2e 00 00 00       	mov    $0x2e,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 51                	ja     0x83
  32:	c3                   	ret
  33:	48 83 ec 28          	sub    $0x28,%rsp
  37:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  3b:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 51                	ja     0x59
   8:	c3                   	ret
   9:	48 83 ec 28          	sub    $0x28,%rsp
   d:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  11:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)
[  191.851761][  T822] RSP: 002b:00007ffe5cf61898 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  191.852010][  T822] RAX: ffffffffffffffda RBX: 00007ffe5cf61fc0 RCX: 00007fbb0ff7c9a7
[  191.852253][  T822] RDX: 0000000000000000 RSI: 00007ffe5cf61900 RDI: 0000000000000005
[  191.852501][  T822] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[  191.852752][  T822] R10: 00007fbb0fe3aef8 R11: 0000000000000246 R12: 0000000000000002


Finger prints:
print_deadlock_bug:validate_chain:__lock_acquire:down_read:blocking_notifier_call_chain