======================================
| [ 18.374580][ T303] #0: ffffffff94407e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 18.374844][ T303] #1: ffffffff943f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   18.375144][  T303]
| [   18.375144][  T303] stack backtrace:
[   18.375548][  T303] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   18.375743][  T303] Call Trace:
[   18.375856][  T303]  <TASK>
[ 18.375932][ T303] dump_stack_lvl (lib/dump_stack.c:123)
[ 18.376087][ T303] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 18.376236][ T303] validate_chain (kernel/locking/lockdep.c:3894)
[ 18.376386][ T303] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 18.376536][ T303] ? 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)
[ 18.376683][ T303] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 18.376795][ T303] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 18.376946][ T303] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 18.377097][ T303] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 18.377279][ T303] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 18.377427][ T303] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 18.377575][ T303] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 18.377721][ T303] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 18.377866][ T303] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 18.378049][ T303] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 18.378166][ T303] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 18.378350][ T303] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 18.378497][ T303] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 18.378644][ T303] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 18.378792][ T303] __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))
[ 18.378959][ T303] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 18.379106][ T303] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 18.379288][ T303] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 18.379474][ T303] ? __try_to_del_timer_sync (kernel/time/timer.c:1498)
[ 18.379620][ T303] ? __pfx___try_to_del_timer_sync (kernel/time/timer.c:1498)
[ 18.379800][ T303] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 18.379947][ T303] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 18.380093][ T303] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 18.380278][ T303] ? 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)
[ 18.380424][ T303] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 18.380574][ T303] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 18.380753][ T303] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804)
[ 18.380900][ T303] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 18.381049][ T303] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 18.381195][ T303] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 18.381377][ T303] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 18.381557][ T303] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 18.381710][ T303] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 18.381859][ T303] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 18.382003][ T303] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 18.382187][ T303] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 18.382368][ T303] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 18.382554][ T303] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 18.382702][ T303] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 18.382868][ T303] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 18.383015][ T303] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 18.383161][ T303] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 18.383306][ T303] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 18.383453][ T303] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 18.383604][ T303] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 18.383750][ T303] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 18.383902][ T303] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 18.384049][ T303] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 18.384194][ T303] ? 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)
[ 18.384340][ T303] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 18.384453][ T303] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 18.384602][ T303] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 18.384748][ T303] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 18.384897][ T303] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 18.385048][ T303] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 18.385197][ T303] ? 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)
[ 18.385345][ T303] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 18.385491][ T303] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 18.385638][ T303] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 18.385786][ T303] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 18.385937][ T303] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 18.386088][ T303] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 18.386235][ T303] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 18.386383][ T303] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 18.386571][ T303] ___sys_sendmsg (net/socket.c:2650)
[ 18.386718][ T303] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 18.386865][ T303] ? kasan_save_stack (mm/kasan/common.c:49)
[ 18.387013][ T303] ? kasan_save_stack (mm/kasan/common.c:48)
[ 18.387158][ T303] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 18.387303][ T303] ? __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)
[ 18.387485][ T303] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 18.387634][ T303] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 18.387780][ T303] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 18.387960][ T303] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 18.388110][ T303] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 18.388260][ T303] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 18.388404][ T303] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 18.388549][ T303] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 18.388695][ T303] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 18.388850][ T303] __sys_sendmsg (net/socket.c:2680)
[ 18.389010][ T303] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 18.389153][ T303] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 18.389348][ T303] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 18.389495][ T303] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   18.389683][  T303] RIP: 0033:0x7fb0c14b99a7
[ 18.389836][ T303] 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)
[   18.390348][  T303] RSP: 002b:00007ffe3aff4298 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   18.390575][  T303] RAX: ffffffffffffffda RBX: 00007ffe3aff49c0 RCX: 00007fb0c14b99a7
[   18.390793][  T303] RDX: 0000000000000000 RSI: 00007ffe3aff4300 RDI: 0000000000000005
[   18.391011][  T303] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   18.391232][  T303] R10: 00007fb0c1377ef8 R11: 0000000000000246 R12: 0000000000000002


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