======================================
| [ 625.393438][ T8054] #0: ffffffffa7601dc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3512)
| [ 625.393873][ T8054] #1: ffffffffa75f0a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  625.394363][ T8054]
| [  625.394363][ T8054] stack backtrace:
[  625.395013][ T8054] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  625.395312][ T8054] Call Trace:
[  625.395494][ T8054]  <TASK>
[ 625.395617][ T8054] dump_stack_lvl (lib/dump_stack.c:123)
[ 625.395862][ T8054] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 625.396106][ T8054] validate_chain (kernel/locking/lockdep.c:3894)
[ 625.396345][ T8054] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 625.396594][ T8054] ? 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)
[ 625.396833][ T8054] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 625.397054][ T8054] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 625.397311][ T8054] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 625.397572][ T8054] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 625.397882][ T8054] ? validate_chain (kernel/locking/lockdep.c:3915)
[ 625.398139][ T8054] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 625.398390][ T8054] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 625.398643][ T8054] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 625.398894][ T8054] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 625.399216][ T8054] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 625.399413][ T8054] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 625.399718][ T8054] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 625.399961][ T8054] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 625.400217][ T8054] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 625.400439][ T8054] __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))
[ 625.400661][ T8054] ? br_fdb_delete_by_port (net/bridge/br_fdb.c:768)
[ 625.400906][ T8054] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 625.401211][ T8054] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 625.401446][ T8054] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359)
[ 625.401624][ T8054] ? 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)
[ 625.401873][ T8054] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 625.402126][ T8054] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 625.402423][ T8054] ? mutex_spin_on_owner (kernel/locking/mutex.c:332)
[ 625.402665][ T8054] ? rtnl_is_locked (net/core/rtnetlink.c:164)
[ 625.402921][ T8054] ? nbp_backup_change (net/bridge/br_if.c:185 (discriminator 9))
[ 625.403165][ T8054] del_nbp (net/bridge/br_if.c:365)
[ 625.403355][ T8054] br_del_if (net/bridge/br_if.c:741)
[ 625.403545][ T8054] br_device_event (net/bridge/br.c:123)
[ 625.403783][ T8054] ? __pfx_br_device_event (net/bridge/br.c:29)
[ 625.404043][ T8054] ? packet_notifier (net/packet/af_packet.c:4282)
[ 625.404292][ T8054] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 625.404544][ T8054] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 625.404798][ T8054] unregister_netdevice_many_notify (net/core/dev.c:11571)
[ 625.405112][ T8054] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11512)
[ 625.405425][ T8054] ? rtnl_dellink (net/core/rtnetlink.c:3512)
[ 625.405682][ T8054] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 625.405937][ T8054] ? rtnl_is_locked (net/core/rtnetlink.c:164)
[ 625.406189][ T8054] ? unregister_netdevice_queue (net/core/dev.c:11497)
[ 625.406502][ T8054] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11496)
[ 625.406810][ T8054] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11496)
[ 625.407126][ T8054] rtnl_dellink (net/core/rtnetlink.c:3478 net/core/rtnetlink.c:3518)
[ 625.407395][ T8054] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3484)
[ 625.407676][ T8054] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 625.407927][ T8054] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 625.408176][ T8054] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[ 625.408433][ T8054] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 625.408691][ T8054] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 625.408949][ T8054] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[ 625.409200][ T8054] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3484)
[ 625.409456][ T8054] rtnetlink_rcv_msg (net/core/rtnetlink.c:6902)
[ 625.409711][ T8054] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 625.409968][ T8054] ? 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)
[ 625.410219][ T8054] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 625.410423][ T8054] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 625.410680][ T8054] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 625.410939][ T8054] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 625.411200][ T8054] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 625.411451][ T8054] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 625.411703][ T8054] ? 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)
[ 625.411962][ T8054] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 625.412229][ T8054] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 625.412481][ T8054] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 625.412735][ T8054] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 625.412986][ T8054] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 625.413247][ T8054] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 625.413506][ T8054] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 625.413759][ T8054] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 625.414089][ T8054] ___sys_sendmsg (net/socket.c:2650)
[ 625.414343][ T8054] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 625.414596][ T8054] ? kasan_save_stack (mm/kasan/common.c:49)
[ 625.414849][ T8054] ? kasan_save_stack (mm/kasan/common.c:48)
[ 625.415121][ T8054] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 625.415368][ T8054] ? __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)
[ 625.415668][ T8054] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 625.415915][ T8054] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 625.416155][ T8054] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 625.416462][ T8054] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 625.416705][ T8054] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 625.416935][ T8054] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 625.417168][ T8054] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 625.417419][ T8054] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 625.417655][ T8054] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 625.417896][ T8054] __sys_sendmsg (net/socket.c:2680)
[ 625.418135][ T8054] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 625.418370][ T8054] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 625.418679][ T8054] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 625.418911][ T8054] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  625.419199][ T8054] RIP: 0033:0x7ff269ed99a7
[ 625.419446][ T8054] 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)
[  625.420261][ T8054] RSP: 002b:00007ffc6b056158 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  625.420627][ T8054] RAX: ffffffffffffffda RBX: 00007ffc6b056890 RCX: 00007ff269ed99a7
[  625.420992][ T8054] RDX: 0000000000000000 RSI: 00007ffc6b0561c0 RDI: 0000000000000005
[  625.421347][ T8054] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[  625.421699][ T8054] R10: 00007ff269d974a8 R11: 0000000000000246 R12: 0000000000000001


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