======================================
| [ 27.570570][ T427] #0: ffffffffa4a07e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 27.570839][ T427] #1: ffffffffa49f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   27.571137][  T427]
| [   27.571137][  T427] stack backtrace:
[   27.571551][  T427] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   27.571729][  T427] Call Trace:
[   27.571839][  T427]  <TASK>
[ 27.571917][ T427] dump_stack_lvl (lib/dump_stack.c:123)
[ 27.572089][ T427] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 27.572242][ T427] validate_chain (kernel/locking/lockdep.c:3894)
[ 27.572391][ T427] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.572550][ T427] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 27.572700][ T427] ? 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)
[ 27.572848][ T427] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 27.572962][ T427] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.573113][ T427] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 27.573262][ T427] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.573458][ T427] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.573606][ T427] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 27.573751][ T427] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 27.573895][ T427] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.574094][ T427] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 27.574210][ T427] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.574396][ T427] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 27.574546][ T427] ? __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)
[ 27.574696][ T427] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.574843][ T427] __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))
[ 27.574995][ T427] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 27.575181][ T427] ? synchronize_rcu_expedited (kernel/rcu/tree_exp.h:995 (discriminator 1))
[ 27.575369][ T427] ? __pfx_autoremove_wake_function (kernel/sched/wait.c:383)
[ 27.575554][ T427] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 27.575704][ T427] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 27.575858][ T427] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 27.576057][ T427] ? 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)
[ 27.576213][ T427] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 27.576361][ T427] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 27.576541][ T427] ovs_netdev_detach_dev (net/openvswitch/vport-netdev.c:158 (discriminator 11)) openvswitch
[ 27.576738][ T427] ? ovs_netdev_get_vport (net/openvswitch/vport-netdev.c:196 (discriminator 3)) openvswitch
[ 27.576934][ T427] dp_device_event (net/openvswitch/dp_notify.c:77) openvswitch
[ 27.577133][ T427] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 27.577281][ T427] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 27.577439][ T427] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 27.577617][ T427] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 27.577814][ T427] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 27.577961][ T427] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 27.578117][ T427] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 27.578266][ T427] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 27.578446][ T427] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 27.578629][ T427] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 27.578810][ T427] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 27.578957][ T427] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 27.579118][ T427] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.579265][ T427] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 27.579420][ T427] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 27.579562][ T427] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 27.579705][ T427] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.579851][ T427] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 27.579995][ T427] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 27.580138][ T427] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 27.580282][ T427] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 27.580429][ T427] ? 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)
[ 27.580571][ T427] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 27.580681][ T427] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.580825][ T427] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 27.580970][ T427] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 27.581112][ T427] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 27.581279][ T427] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 27.581438][ T427] ? 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)
[ 27.581583][ T427] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 27.581726][ T427] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 27.581886][ T427] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.582037][ T427] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 27.582186][ T427] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 27.582335][ T427] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 27.582482][ T427] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 27.582629][ T427] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 27.582816][ T427] ___sys_sendmsg (net/socket.c:2650)
[ 27.582961][ T427] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 27.583107][ T427] ? kasan_save_stack (mm/kasan/common.c:49)
[ 27.583255][ T427] ? kasan_save_stack (mm/kasan/common.c:48)
[ 27.583411][ T427] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 27.583553][ T427] ? __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)
[ 27.583733][ T427] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 27.583876][ T427] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 27.584022][ T427] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 27.584199][ T427] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.584343][ T427] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.584486][ T427] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 27.584630][ T427] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 27.584778][ T427] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 27.584920][ T427] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.585067][ T427] __sys_sendmsg (net/socket.c:2680)
[ 27.585209][ T427] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 27.585352][ T427] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 27.585534][ T427] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 27.585678][ T427] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   27.585857][  T427] RIP: 0033:0x7fdfadd7f9a7
[ 27.586026][ T427] 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)
[   27.586579][  T427] RSP: 002b:00007fff0a9f8cc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   27.586803][  T427] RAX: ffffffffffffffda RBX: 00007fff0a9f93f0 RCX: 00007fdfadd7f9a7
[   27.587025][  T427] RDX: 0000000000000000 RSI: 00007fff0a9f8d30 RDI: 0000000000000005
[   27.587244][  T427] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[   27.587474][  T427] R10: 00007fdfadc3def8 R11: 0000000000000246 R12: 0000000000000001


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