======================================
| [ 42.931443][ T615] #0: ffffffffa05e7a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 42.931722][ T615] #1: ffffffffa05d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   42.932046][  T615]
| [   42.932046][  T615] stack backtrace:
[   42.932499][  T615] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   42.932719][  T615] Call Trace:
[   42.932840][  T615]  <TASK>
[ 42.932921][ T615] dump_stack_lvl (lib/dump_stack.c:123)
[ 42.933095][ T615] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 42.933279][ T615] validate_chain (kernel/locking/lockdep.c:3894)
[ 42.933434][ T615] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 42.933590][ T615] ? 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)
[ 42.933743][ T615] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 42.933862][ T615] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.934017][ T615] ? 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)
[ 42.934172][ T615] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 42.934337][ T615] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.934537][ T615] ? validate_chain (kernel/locking/lockdep.c:3915)
[ 42.934690][ T615] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.934849][ T615] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 42.935007][ T615] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 42.935175][ T615] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.935377][ T615] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 42.935508][ T615] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.935708][ T615] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 42.935870][ T615] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.936030][ T615] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 42.936191][ T615] __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))
[ 42.936346][ T615] ? br_fdb_delete_by_port (net/bridge/br_fdb.c:768) bridge
[ 42.936600][ T615] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 42.936807][ T615] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.936976][ T615] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359) bridge
[ 42.937196][ T615] ? 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)
[ 42.937355][ T615] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 42.937519][ T615] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 42.937726][ T615] ? mutex_spin_on_owner (kernel/locking/mutex.c:332)
[ 42.937898][ T615] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 42.938069][ T615] del_nbp (net/bridge/br_if.c:365) bridge
[ 42.938281][ T615] br_del_if (net/bridge/br_if.c:741) bridge
[ 42.938483][ T615] br_device_event (net/bridge/br.c:141) bridge
[ 42.938671][ T615] ? __pfx_br_device_event (net/bridge/br.c:29) bridge
[ 42.938892][ T615] ? netconsole_netdev_event (drivers/net/netconsole.c:1082)
[ 42.939047][ T615] ? packet_notifier (net/packet/af_packet.c:4282)
[ 42.939222][ T615] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 42.939384][ T615] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 42.939546][ T615] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 42.939735][ T615] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.939989][ T615] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.940148][ T615] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 42.940344][ T615] ? 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)
[ 42.940507][ T615] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 42.940664][ T615] ? __pfx_vlan_info_rcu_free (net/8021q/vlan_core.c:145)
[ 42.940831][ T615] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 42.941028][ T615] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 42.941189][ T615] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 42.941362][ T615] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.941519][ T615] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.941674][ T615] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 42.941832][ T615] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.941990][ T615] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.942149][ T615] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 42.942304][ T615] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 42.942465][ T615] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 42.942623][ T615] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 42.942779][ T615] ? 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)
[ 42.942934][ T615] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 42.943063][ T615] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.943223][ T615] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 42.943383][ T615] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 42.943542][ T615] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 42.943703][ T615] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 42.943863][ T615] ? 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)
[ 42.944023][ T615] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 42.944188][ T615] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 42.944347][ T615] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.944507][ T615] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 42.944665][ T615] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 42.944826][ T615] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 42.944989][ T615] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 42.945157][ T615] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 42.945378][ T615] ___sys_sendmsg (net/socket.c:2650)
[ 42.945536][ T615] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 42.945695][ T615] ? kasan_save_stack (mm/kasan/common.c:49)
[ 42.945854][ T615] ? kasan_save_stack (mm/kasan/common.c:48)
[ 42.946013][ T615] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 42.946175][ T615] ? __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)
[ 42.946378][ T615] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 42.946537][ T615] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 42.946698][ T615] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 42.946900][ T615] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 42.947060][ T615] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 42.947236][ T615] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 42.947395][ T615] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 42.947557][ T615] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 42.947716][ T615] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 42.947880][ T615] __sys_sendmsg (net/socket.c:2680)
[ 42.948038][ T615] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 42.948198][ T615] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 42.948401][ T615] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 42.948558][ T615] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   42.948752][  T615] RIP: 0033:0x7f215a13b9a7
[ 42.948923][ T615] 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)
[   42.949489][  T615] RSP: 002b:00007ffdc2dd1228 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   42.949730][  T615] RAX: ffffffffffffffda RBX: 00007ffdc2dd1950 RCX: 00007f215a13b9a7
[   42.949971][  T615] RDX: 0000000000000000 RSI: 00007ffdc2dd1290 RDI: 0000000000000005
[   42.950216][  T615] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   42.950456][  T615] R10: 00007f2159ff9ef8 R11: 0000000000000246 R12: 0000000000000002


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