======================================
| [ 32.609818][ T420] #0: ffffffff9e1e7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 32.610095][ T420] #1: ffffffff9e1d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   32.610391][  T420]
| [   32.610391][  T420] stack backtrace:
[   32.610790][  T420] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   32.610976][  T420] Call Trace:
[   32.611088][  T420]  <TASK>
[ 32.611166][ T420] dump_stack_lvl (lib/dump_stack.c:123)
[ 32.611320][ T420] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 32.611469][ T420] validate_chain (kernel/locking/lockdep.c:3894)
[ 32.611616][ T420] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 32.611767][ T420] ? 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)
[ 32.611914][ T420] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 32.612032][ T420] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 32.612179][ T420] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 32.612324][ T420] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 32.612508][ T420] ? netconsole_process_cleanups_core (drivers/net/netconsole.c:242 (discriminator 11))
[ 32.612692][ T420] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 32.612840][ T420] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 32.612987][ T420] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 32.613136][ T420] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 32.613319][ T420] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 32.613431][ T420] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 32.613612][ T420] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 32.613757][ T420] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 32.613903][ T420] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 32.614050][ T420] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 32.614204][ T420] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 32.614349][ T420] __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))
[ 32.614498][ T420] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 32.614685][ T420] ? __mutex_unlock_slowpath (./arch/x86/include/asm/atomic64_64.h:101 ./include/linux/atomic/atomic-arch-fallback.h:4329 ./include/linux/atomic/atomic-long.h:1506 ./include/linux/atomic/atomic-instrumented.h:4481 kernel/locking/mutex.c:913)
[ 32.614833][ T420] ? __pfx___mutex_unlock_slowpath (kernel/locking/mutex.c:890)
[ 32.615015][ T420] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 32.615164][ T420] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 32.615315][ T420] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 32.615498][ T420] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 32.615646][ T420] ? 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)
[ 32.615793][ T420] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 32.615938][ T420] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 32.616120][ T420] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804) vrf
[ 32.616276][ T420] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 32.616424][ T420] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 32.616572][ T420] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 32.616786][ T420] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 32.616949][ T420] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 32.617115][ T420] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 32.617319][ T420] ? 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)
[ 32.617486][ T420] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 32.617652][ T420] ? __pfx_vlan_info_rcu_free (net/8021q/vlan_core.c:145)
[ 32.617817][ T420] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 32.618026][ T420] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 32.618191][ T420] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 32.618369][ T420] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 32.618538][ T420] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 32.618705][ T420] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 32.618872][ T420] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 32.619036][ T420] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 32.619214][ T420] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 32.619380][ T420] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 32.619546][ T420] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 32.619712][ T420] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 32.619883][ T420] ? 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)
[ 32.620048][ T420] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 32.620174][ T420] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 32.620338][ T420] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 32.620505][ T420] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 32.620673][ T420] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 32.620842][ T420] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 32.621009][ T420] ? 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)
[ 32.621180][ T420] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 32.621347][ T420] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 32.621511][ T420] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 32.621678][ T420] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 32.621843][ T420] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 32.622011][ T420] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 32.622175][ T420] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 32.622345][ T420] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 32.622554][ T420] ___sys_sendmsg (net/socket.c:2650)
[ 32.622719][ T420] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 32.622885][ T420] ? kasan_save_stack (mm/kasan/common.c:49)
[ 32.623049][ T420] ? kasan_save_stack (mm/kasan/common.c:48)
[ 32.623217][ T420] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 32.623383][ T420] ? __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)
[ 32.623595][ T420] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 32.623760][ T420] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 32.623928][ T420] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 32.624136][ T420] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 32.624302][ T420] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 32.624468][ T420] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 32.624632][ T420] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 32.624803][ T420] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 32.624968][ T420] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 32.625135][ T420] __sys_sendmsg (net/socket.c:2680)
[ 32.625300][ T420] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 32.625469][ T420] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 32.625678][ T420] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 32.625842][ T420] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   32.626052][  T420] RIP: 0033:0x7f84eb1039a7
[ 32.626225][ T420] 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)
[   32.626800][  T420] RSP: 002b:00007ffcc9d720a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   32.627050][  T420] RAX: ffffffffffffffda RBX: 00007ffcc9d727d0 RCX: 00007f84eb1039a7
[   32.627305][  T420] RDX: 0000000000000000 RSI: 00007ffcc9d72110 RDI: 0000000000000005
[   32.627552][  T420] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   32.627799][  T420] R10: 00007f84eafc1ef8 R11: 0000000000000246 R12: 0000000000000002


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