======================================
| [836.181592][T10536] #0: ffffffff9c7e7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [836.181904][T10536] #1: ffffffff9c7d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  836.182241][T10536]
| [  836.182241][T10536] stack backtrace:
[  836.182688][T10536] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  836.182900][T10536] Call Trace:
[  836.183038][T10536]  <TASK>
[836.183125][T10536] dump_stack_lvl (lib/dump_stack.c:123)
[836.183295][T10536] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[836.183474][T10536] validate_chain (kernel/locking/lockdep.c:3894)
[836.183633][T10536] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[836.183804][T10536] ? 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)
[836.183976][T10536] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[836.184109][T10536] __lock_acquire (kernel/locking/lockdep.c:5226)
[836.184281][T10536] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[836.184435][T10536] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[836.184651][T10536] ? netconsole_process_cleanups_core (drivers/net/netconsole.c:242 (discriminator 11))
[836.184861][T10536] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[836.185028][T10536] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[836.185197][T10536] ? lock_acquire (kernel/locking/lockdep.c:5822)
[836.185359][T10536] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[836.185563][T10536] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[836.185682][T10536] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[836.185886][T10536] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[836.186050][T10536] ? __lock_release (kernel/locking/lockdep.c:5525)
[836.186214][T10536] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[836.186376][T10536] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[836.186536][T10536] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[836.186702][T10536] __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))
[836.186867][T10536] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[836.187071][T10536] ? __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)
[836.187240][T10536] ? __pfx___mutex_unlock_slowpath (kernel/locking/mutex.c:890)
[836.187440][T10536] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[836.187601][T10536] netdev_upper_dev_unlink (net/core/dev.c:8190)
[836.187764][T10536] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[836.187979][T10536] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[836.188140][T10536] ? 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)
[836.188300][T10536] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[836.188456][T10536] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[836.188652][T10536] vrf_device_event (drivers/net/vrf.c:1110 drivers/net/vrf.c:1119 drivers/net/vrf.c:1804) vrf
[836.188818][T10536] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[836.188981][T10536] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[836.189167][T10536] unregister_netdevice_many_notify (net/core/dev.c:11575)
[836.189389][T10536] ? 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)
[836.189555][T10536] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[836.189684][T10536] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[836.189882][T10536] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[836.190087][T10536] ? kfree (mm/slub.c:4613 mm/slub.c:4761)
[836.190225][T10536] ? vlan_vid_del (net/8021q/vlan_core.c:368 net/8021q/vlan_core.c:387)
[836.190397][T10536] ? vlan_vid_del (net/8021q/vlan_core.c:368 net/8021q/vlan_core.c:387)
[836.190566][T10536] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[836.190733][T10536] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[836.190915][T10536] ? find_held_lock (kernel/locking/lockdep.c:5339)
[836.191079][T10536] ? __lock_release (kernel/locking/lockdep.c:5525)
[836.191236][T10536] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[836.191406][T10536] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[836.191571][T10536] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[836.191750][T10536] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[836.191909][T10536] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[836.192081][T10536] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[836.192238][T10536] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[836.192414][T10536] ? 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)
[836.192574][T10536] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[836.192695][T10536] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[836.192866][T10536] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[836.193025][T10536] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[836.193205][T10536] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[836.193380][T10536] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[836.193560][T10536] ? 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)
[836.193737][T10536] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[836.193911][T10536] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[836.194082][T10536] ? find_held_lock (kernel/locking/lockdep.c:5339)
[836.194256][T10536] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[836.194416][T10536] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[836.194576][T10536] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[836.194737][T10536] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[836.194899][T10536] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[836.195098][T10536] ___sys_sendmsg (net/socket.c:2650)
[836.195258][T10536] ? __pfx____sys_sendmsg (net/socket.c:2637)
[836.195417][T10536] ? kasan_save_stack (mm/kasan/common.c:49)
[836.195573][T10536] ? kasan_save_stack (mm/kasan/common.c:48)
[836.195727][T10536] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[836.195887][T10536] ? __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)
[836.196091][T10536] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[836.196254][T10536] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[836.196412][T10536] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[836.196615][T10536] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[836.196784][T10536] ? find_held_lock (kernel/locking/lockdep.c:5339)
[836.196944][T10536] ? __lock_release (kernel/locking/lockdep.c:5525)
[836.197101][T10536] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[836.197259][T10536] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[836.197418][T10536] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[836.197584][T10536] __sys_sendmsg (net/socket.c:2680)
[836.197747][T10536] ? __pfx___sys_sendmsg (net/socket.c:2665)
[836.197906][T10536] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[836.198108][T10536] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[836.198265][T10536] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  836.198458][T10536] RIP: 0033:0x7fcb9521e9a7
[ 836.198626][T10536] 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)
[  836.199193][T10536] RSP: 002b:00007ffdd19b2fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  836.199437][T10536] RAX: ffffffffffffffda RBX: 00007ffdd19b3710 RCX: 00007fcb9521e9a7
[  836.199677][T10536] RDX: 0000000000000000 RSI: 00007ffdd19b3050 RDI: 0000000000000005
[  836.199923][T10536] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[  836.200170][T10536] R10: 00007fcb950dcef8 R11: 0000000000000246 R12: 0000000000000002


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