======================================
| [ 1256.361662][ T4447] #0: ffffffffb47e7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 1256.361934][ T4447] #1: ffffffffb47d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [ 1256.362234][ T4447]
| [ 1256.362234][ T4447] stack backtrace:
[ 1256.362643][ T4447] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1256.362835][ T4447] Call Trace:
[ 1256.362947][ T4447]  <TASK>
[ 1256.363027][ T4447] dump_stack_lvl (lib/dump_stack.c:123)
[ 1256.363192][ T4447] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 1256.363347][ T4447] validate_chain (kernel/locking/lockdep.c:3894)
[ 1256.363497][ T4447] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 1256.363651][ T4447] ? 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)
[ 1256.363811][ T4447] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 1256.363930][ T4447] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 1256.364086][ T4447] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 1256.364237][ T4447] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 1256.364501][ T4447] ? netconsole_process_cleanups_core (drivers/net/netconsole.c:242 (discriminator 11))
[ 1256.364714][ T4447] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 1256.364890][ T4447] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 1256.365038][ T4447] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 1256.365188][ T4447] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 1256.365374][ T4447] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 1256.365492][ T4447] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 1256.365685][ T4447] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 1256.365833][ T4447] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 1256.365980][ T4447] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 1256.366133][ T4447] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 1256.366288][ T4447] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 1256.366442][ T4447] __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))
[ 1256.366592][ T4447] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 1256.366790][ T4447] ? __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)
[ 1256.366939][ T4447] ? __pfx___mutex_unlock_slowpath (kernel/locking/mutex.c:890)
[ 1256.367129][ T4447] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 1256.367282][ T4447] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 1256.367429][ T4447] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 1256.367616][ T4447] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 1256.367776][ T4447] ? 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)
[ 1256.367929][ T4447] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 1256.368078][ T4447] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 1256.368266][ T4447] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804) vrf
[ 1256.368418][ T4447] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 1256.368577][ T4447] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 1256.368769][ T4447] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 1256.368982][ T4447] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 1256.369148][ T4447] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 1256.369314][ T4447] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 1256.369521][ T4447] ? 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)
[ 1256.369686][ T4447] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 1256.369853][ T4447] ? __pfx_vlan_info_rcu_free (net/8021q/vlan_core.c:145)
[ 1256.370022][ T4447] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 1256.370238][ T4447] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 1256.370403][ T4447] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 1256.370582][ T4447] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 1256.370750][ T4447] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 1256.370916][ T4447] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 1256.371079][ T4447] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 1256.371241][ T4447] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 1256.371416][ T4447] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 1256.371583][ T4447] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 1256.371751][ T4447] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 1256.371916][ T4447] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 1256.372082][ T4447] ? 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)
[ 1256.372248][ T4447] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 1256.372373][ T4447] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 1256.372539][ T4447] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 1256.372714][ T4447] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 1256.372881][ T4447] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 1256.373052][ T4447] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 1256.373221][ T4447] ? 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)
[ 1256.373393][ T4447] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 1256.373558][ T4447] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 1256.373732][ T4447] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 1256.373904][ T4447] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 1256.374071][ T4447] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 1256.374241][ T4447] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 1256.374405][ T4447] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 1256.374582][ T4447] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 1256.374794][ T4447] ___sys_sendmsg (net/socket.c:2650)
[ 1256.374962][ T4447] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 1256.375139][ T4447] ? kasan_save_stack (mm/kasan/common.c:49)
[ 1256.375309][ T4447] ? kasan_save_stack (mm/kasan/common.c:48)
[ 1256.375474][ T4447] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 1256.375645][ T4447] ? __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)
[ 1256.375855][ T4447] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 1256.376025][ T4447] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 1256.376192][ T4447] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 1256.376412][ T4447] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 1256.376579][ T4447] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 1256.376748][ T4447] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 1256.376915][ T4447] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 1256.377084][ T4447] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 1256.377247][ T4447] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 1256.377418][ T4447] __sys_sendmsg (net/socket.c:2680)
[ 1256.377592][ T4447] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 1256.377758][ T4447] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 1256.377968][ T4447] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 1256.378132][ T4447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 1256.378338][ T4447] RIP: 0033:0x7fc522d2e9a7
[ 1256.378513][ T4447] 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)
[ 1256.379103][ T4447] RSP: 002b:00007ffd35ba5518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 1256.379352][ T4447] RAX: ffffffffffffffda RBX: 00007ffd35ba5c40 RCX: 00007fc522d2e9a7
[ 1256.379603][ T4447] RDX: 0000000000000000 RSI: 00007ffd35ba5580 RDI: 0000000000000005
[ 1256.379857][ T4447] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[ 1256.380103][ T4447] R10: 00007fc522becef8 R11: 0000000000000246 R12: 0000000000000002


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