======================================
| [ 605.359369][ T8101] #0: ffffffffba801dc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 605.359674][ T8101] #1: ffffffffba7f0a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  605.360008][ T8101]
| [  605.360008][ T8101] stack backtrace:
[  605.360472][ T8101] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  605.360677][ T8101] Call Trace:
[  605.360800][ T8101]  <TASK>
[ 605.360889][ T8101] dump_stack_lvl (lib/dump_stack.c:123)
[ 605.361069][ T8101] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 605.361244][ T8101] validate_chain (kernel/locking/lockdep.c:3894)
[ 605.361406][ T8101] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 605.361582][ T8101] ? 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)
[ 605.361743][ T8101] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 605.361873][ T8101] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 605.362046][ T8101] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 605.362211][ T8101] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 605.362434][ T8101] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 605.362621][ T8101] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 605.362787][ T8101] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 605.362951][ T8101] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 605.363136][ T8101] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 605.363350][ T8101] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 605.363513][ T8101] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 605.363808][ T8101] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 605.363972][ T8101] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406)
[ 605.364180][ T8101] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 605.364343][ T8101] __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))
[ 605.364511][ T8101] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 605.364712][ T8101] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 605.364873][ T8101] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359)
[ 605.365001][ T8101] ? 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)
[ 605.365166][ T8101] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 605.365330][ T8101] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 605.365540][ T8101] ? mutex_spin_on_owner (kernel/locking/mutex.c:332)
[ 605.365706][ T8101] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 605.365875][ T8101] ? nbp_backup_change (net/bridge/br_if.c:185 (discriminator 9))
[ 605.366041][ T8101] del_nbp (net/bridge/br_if.c:365)
[ 605.366165][ T8101] br_del_if (net/bridge/br_if.c:741)
[ 605.366288][ T8101] br_device_event (net/bridge/br.c:123)
[ 605.366457][ T8101] ? __pfx_br_device_event (net/bridge/br.c:29)
[ 605.366641][ T8101] ? packet_notifier (net/packet/af_packet.c:4282)
[ 605.366804][ T8101] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 605.366983][ T8101] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 605.367168][ T8101] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 605.367377][ T8101] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 605.367591][ T8101] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 605.367753][ T8101] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 605.367917][ T8101] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 605.368085][ T8101] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 605.368303][ T8101] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 605.368515][ T8101] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 605.368719][ T8101] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 605.368884][ T8101] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 605.369061][ T8101] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 605.369221][ T8101] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 605.369395][ T8101] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 605.369573][ T8101] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 605.369739][ T8101] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 605.369906][ T8101] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 605.370069][ T8101] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 605.370232][ T8101] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 605.370414][ T8101] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 605.370590][ T8101] ? 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)
[ 605.370752][ T8101] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 605.370877][ T8101] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 605.371045][ T8101] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 605.371217][ T8101] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 605.371386][ T8101] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 605.371635][ T8101] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 605.371833][ T8101] ? 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)
[ 605.371995][ T8101] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 605.372156][ T8101] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 605.372336][ T8101] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 605.372517][ T8101] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 605.372680][ T8101] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 605.372853][ T8101] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 605.373017][ T8101] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 605.373189][ T8101] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 605.373402][ T8101] ___sys_sendmsg (net/socket.c:2650)
[ 605.373565][ T8101] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 605.373729][ T8101] ? kasan_save_stack (mm/kasan/common.c:49)
[ 605.373890][ T8101] ? kasan_save_stack (mm/kasan/common.c:48)
[ 605.374061][ T8101] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 605.374232][ T8101] ? __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)
[ 605.374440][ T8101] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 605.374631][ T8101] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 605.374793][ T8101] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 605.374997][ T8101] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 605.375171][ T8101] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 605.375331][ T8101] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 605.375499][ T8101] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 605.375666][ T8101] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 605.375827][ T8101] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 605.375991][ T8101] __sys_sendmsg (net/socket.c:2680)
[ 605.376149][ T8101] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 605.376316][ T8101] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 605.376530][ T8101] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 605.376692][ T8101] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  605.376901][ T8101] RIP: 0033:0x7f83d15709a7
[ 605.377075][ T8101] 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)
[  605.377643][ T8101] RSP: 002b:00007ffc8c57d9c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  605.377891][ T8101] RAX: ffffffffffffffda RBX: 00007ffc8c57e100 RCX: 00007f83d15709a7
[  605.378134][ T8101] RDX: 0000000000000000 RSI: 00007ffc8c57da30 RDI: 0000000000000005
[  605.378376][ T8101] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[  605.378653][ T8101] R10: 00007f83d142e4a8 R11: 0000000000000246 R12: 0000000000000001


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