======================================
| [ 42.102009][ T636] #0: ffffffffa67e7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 42.102404][ T636] #1: ffffffffa67d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   42.102860][  T636]
| [   42.102860][  T636] stack backtrace:
[   42.103450][  T636] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   42.103727][  T636] Call Trace:
[   42.103908][  T636]  <TASK>
[ 42.104034][ T636] dump_stack_lvl (lib/dump_stack.c:123)
[ 42.104286][ T636] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 42.104540][ T636] validate_chain (kernel/locking/lockdep.c:3894)
[ 42.104800][ T636] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 42.105020][ T636] ? 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)
[ 42.105282][ T636] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 42.105480][ T636] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.105733][ T636] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 42.105978][ T636] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.106289][ T636] ? netconsole_process_cleanups_core (drivers/net/netconsole.c:242 (discriminator 11))
[ 42.106611][ T636] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.106857][ T636] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 42.107084][ T636] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 42.107264][ T636] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.107581][ T636] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 42.107769][ T636] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.108073][ T636] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 42.108326][ T636] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.108578][ T636] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 42.108832][ T636] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.109077][ T636] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.109325][ T636] __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))
[ 42.109578][ T636] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 42.109886][ T636] ? __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)
[ 42.110101][ T636] ? __pfx___mutex_unlock_slowpath (kernel/locking/mutex.c:890)
[ 42.110322][ T636] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 42.110547][ T636] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 42.110781][ T636] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 42.111069][ T636] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 42.111306][ T636] ? 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)
[ 42.111521][ T636] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 42.111759][ T636] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 42.112058][ T636] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804) vrf
[ 42.112291][ T636] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 42.112532][ T636] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 42.112763][ T636] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 42.113047][ T636] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.113282][ T636] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.113522][ T636] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 42.113804][ T636] ? 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)
[ 42.114039][ T636] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 42.114274][ T636] ? __pfx_vlan_info_rcu_free (net/8021q/vlan_core.c:145)
[ 42.114525][ T636] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 42.114811][ T636] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 42.115049][ T636] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 42.115379][ T636] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.115546][ T636] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.115694][ T636] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 42.115842][ T636] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.115990][ T636] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.116138][ T636] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 42.116291][ T636] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 42.116439][ T636] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 42.116586][ T636] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 42.116734][ T636] ? 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)
[ 42.116880][ T636] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 42.116994][ T636] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.117141][ T636] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 42.117288][ T636] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 42.117437][ T636] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 42.117591][ T636] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 42.117741][ T636] ? 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)
[ 42.117889][ T636] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 42.118035][ T636] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 42.118180][ T636] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.118331][ T636] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 42.118482][ T636] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 42.118631][ T636] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 42.118783][ T636] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 42.118931][ T636] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 42.119116][ T636] ___sys_sendmsg (net/socket.c:2650)
[ 42.119267][ T636] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 42.119469][ T636] ? kasan_save_stack (mm/kasan/common.c:49)
[ 42.119677][ T636] ? kasan_save_stack (mm/kasan/common.c:48)
[ 42.119827][ T636] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 42.119974][ T636] ? __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)
[ 42.120158][ T636] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 42.120310][ T636] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 42.120457][ T636] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 42.120640][ T636] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.120804][ T636] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.120951][ T636] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.121098][ T636] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 42.121250][ T636] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.121398][ T636] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.121548][ T636] __sys_sendmsg (net/socket.c:2680)
[ 42.121695][ T636] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 42.121845][ T636] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 42.122033][ T636] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 42.122182][ T636] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   42.122366][  T636] RIP: 0033:0x7fda36e789a7
[ 42.122522][ T636] 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)
[   42.123044][  T636] RSP: 002b:00007ffebeea4ee8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   42.123274][  T636] RAX: ffffffffffffffda RBX: 00007ffebeea5610 RCX: 00007fda36e789a7
[   42.123495][  T636] RDX: 0000000000000000 RSI: 00007ffebeea4f50 RDI: 0000000000000005
[   42.123715][  T636] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   42.123935][  T636] R10: 00007fda36d36ef8 R11: 0000000000000246 R12: 0000000000000002


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