======================================
| [ 27.856288][ T375] #0: ffffffff96bf1088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 27.856573][ T375] #1: ffffffff96bdfc30 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   27.856880][  T375]
| [   27.856880][  T375] stack backtrace:
[   27.857307][  T375] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   27.857498][  T375] Call Trace:
[   27.857619][  T375]  <TASK>
[ 27.857699][ T375] dump_stack_lvl (lib/dump_stack.c:123)
[ 27.857860][ T375] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 27.858022][ T375] validate_chain (kernel/locking/lockdep.c:3894)
[ 27.858179][ T375] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 27.858336][ T375] ? 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)
[ 27.858497][ T375] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 27.858614][ T375] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.858770][ T375] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 27.858924][ T375] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.859112][ T375] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.859267][ T375] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.859419][ T375] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 27.859582][ T375] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 27.859750][ T375] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.859941][ T375] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 27.860058][ T375] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.860249][ T375] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 27.860401][ T375] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406)
[ 27.860592][ T375] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 27.860751][ T375] __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))
[ 27.860915][ T375] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 27.861104][ T375] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.861259][ T375] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359) bridge
[ 27.861450][ T375] ? 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)
[ 27.861603][ T375] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 27.861760][ T375] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 27.861953][ T375] ? mutex_spin_on_owner (kernel/locking/mutex.c:353)
[ 27.862109][ T375] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 27.862264][ T375] del_nbp (net/bridge/br_if.c:365) bridge
[ 27.862447][ T375] br_del_if (net/bridge/br_if.c:741) bridge
[ 27.862629][ T375] br_device_event (net/bridge/br.c:141) bridge
[ 27.862811][ T375] ? __pfx_br_device_event (net/bridge/br.c:29) bridge
[ 27.863026][ T375] ? ip_vs_dst_event (./include/net/net_namespace.h:393 ./include/linux/netdevice.h:2639 net/netfilter/ipvs/ip_vs_ctl.c:1769) ip_vs
[ 27.863200][ T375] ? packet_notifier (net/packet/af_packet.c:4282)
[ 27.863355][ T375] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 27.863509][ T375] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 27.863675][ T375] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 27.863874][ T375] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 27.864064][ T375] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 27.864217][ T375] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 27.864378][ T375] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 27.864531][ T375] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 27.864720][ T375] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 27.864919][ T375] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 27.865110][ T375] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 27.865267][ T375] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 27.865434][ T375] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.865591][ T375] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 27.865761][ T375] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 27.865917][ T375] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 27.866072][ T375] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.866227][ T375] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 27.866379][ T375] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 27.866532][ T375] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 27.866690][ T375] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 27.866846][ T375] ? 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)
[ 27.866999][ T375] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 27.867116][ T375] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.867270][ T375] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 27.867428][ T375] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 27.867581][ T375] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 27.867748][ T375] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 27.867912][ T375] ? 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)
[ 27.868067][ T375] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 27.868220][ T375] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 27.868371][ T375] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.868530][ T375] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 27.868686][ T375] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 27.868846][ T375] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 27.869013][ T375] ? _copy_from_user (./arch/x86/include/asm/smap.h:33 ./arch/x86/include/asm/uaccess_64.h:134 ./arch/x86/include/asm/uaccess_64.h:141 ./include/linux/uaccess.h:178 lib/usercopy.c:18)
[ 27.869174][ T375] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 27.869330][ T375] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 27.869483][ T375] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 27.869682][ T375] ___sys_sendmsg (net/socket.c:2650)
[ 27.869843][ T375] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 27.869998][ T375] ? kasan_save_stack (mm/kasan/common.c:49)
[ 27.870161][ T375] ? kasan_save_stack (mm/kasan/common.c:48)
[ 27.870315][ T375] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 27.870470][ T375] ? __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)
[ 27.870662][ T375] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 27.870819][ T375] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 27.870977][ T375] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 27.871167][ T375] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 27.871335][ T375] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 27.871488][ T375] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 27.871642][ T375] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 27.871806][ T375] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 27.871959][ T375] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 27.872113][ T375] __sys_sendmsg (net/socket.c:2680)
[ 27.872267][ T375] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 27.872423][ T375] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 27.872620][ T375] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 27.872775][ T375] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   27.872965][  T375] RIP: 0033:0x7f188555d9a7
[ 27.873129][ T375] 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)
[   27.873681][  T375] RSP: 002b:00007ffc28a35808 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   27.873920][  T375] RAX: ffffffffffffffda RBX: 00007ffc28a35f30 RCX: 00007f188555d9a7
[   27.874153][  T375] RDX: 0000000000000000 RSI: 00007ffc28a35870 RDI: 0000000000000005
[   27.874382][  T375] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[   27.874618][  T375] R10: 00007f188541bef8 R11: 0000000000000246 R12: 0000000000000001


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