======================================
| [ 17.977858][ T304] #0: ffffffffa5c07e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 17.978122][ T304] #1: ffffffffa5bf6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   17.978423][  T304]
| [   17.978423][  T304] stack backtrace:
[   17.978825][  T304] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   17.979010][  T304] Call Trace:
[   17.979123][  T304]  <TASK>
[ 17.979201][ T304] dump_stack_lvl (lib/dump_stack.c:123)
[ 17.979353][ T304] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 17.979504][ T304] validate_chain (kernel/locking/lockdep.c:3894)
[ 17.979653][ T304] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 17.979800][ T304] ? 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)
[ 17.979947][ T304] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 17.980060][ T304] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 17.980211][ T304] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 17.980356][ T304] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 17.980538][ T304] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 17.980686][ T304] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 17.980835][ T304] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 17.980983][ T304] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 17.981133][ T304] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 17.981316][ T304] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 17.981429][ T304] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 17.981612][ T304] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 17.981775][ T304] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 17.981922][ T304] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 17.982067][ T304] __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))
[ 17.982216][ T304] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 17.982361][ T304] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 17.982542][ T304] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 17.982724][ T304] ? __try_to_del_timer_sync (kernel/time/timer.c:1498)
[ 17.982871][ T304] ? __pfx___try_to_del_timer_sync (kernel/time/timer.c:1498)
[ 17.983054][ T304] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 17.983198][ T304] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 17.983345][ T304] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 17.983525][ T304] ? 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)
[ 17.983671][ T304] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 17.983815][ T304] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 17.983994][ T304] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804)
[ 17.984141][ T304] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 17.984289][ T304] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 17.984438][ T304] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 17.984619][ T304] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 17.984800][ T304] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 17.984945][ T304] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 17.985092][ T304] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 17.985236][ T304] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 17.985417][ T304] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 17.985601][ T304] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 17.985784][ T304] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 17.985930][ T304] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 17.986090][ T304] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 17.986235][ T304] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 17.986379][ T304] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 17.986524][ T304] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 17.986673][ T304] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 17.986820][ T304] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 17.986964][ T304] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 17.987110][ T304] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 17.987254][ T304] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 17.987398][ T304] ? 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)
[ 17.987540][ T304] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 17.987656][ T304] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 17.987802][ T304] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 17.987948][ T304] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 17.988094][ T304] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 17.988244][ T304] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 17.988391][ T304] ? 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)
[ 17.988538][ T304] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 17.988686][ T304] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 17.988831][ T304] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 17.988978][ T304] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 17.989123][ T304] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 17.989270][ T304] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 17.989416][ T304] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 17.989559][ T304] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 17.989745][ T304] ___sys_sendmsg (net/socket.c:2650)
[ 17.989890][ T304] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 17.990036][ T304] ? kasan_save_stack (mm/kasan/common.c:49)
[ 17.990184][ T304] ? kasan_save_stack (mm/kasan/common.c:48)
[ 17.990328][ T304] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 17.990473][ T304] ? __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)
[ 17.990657][ T304] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 17.990806][ T304] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 17.990951][ T304] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 17.991131][ T304] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 17.991279][ T304] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 17.991423][ T304] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 17.991568][ T304] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 17.991732][ T304] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 17.991878][ T304] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 17.992028][ T304] __sys_sendmsg (net/socket.c:2680)
[ 17.992173][ T304] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 17.992319][ T304] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 17.992506][ T304] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 17.992651][ T304] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   17.992830][  T304] RIP: 0033:0x7f23c82ea9a7
[ 17.992987][ T304] 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)
[   17.993499][  T304] RSP: 002b:00007ffd521ab408 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   17.993721][  T304] RAX: ffffffffffffffda RBX: 00007ffd521abb30 RCX: 00007f23c82ea9a7
[   17.993939][  T304] RDX: 0000000000000000 RSI: 00007ffd521ab470 RDI: 0000000000000005
[   17.994156][  T304] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   17.994374][  T304] R10: 00007f23c81a8ef8 R11: 0000000000000246 R12: 0000000000000002


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