======================================
| [ 589.336693][ T8479] #0: ffffffff9f801dc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 589.337024][ T8479] #1: ffffffff9f7f0a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  589.337399][ T8479]
| [  589.337399][ T8479] stack backtrace:
[  589.337814][ T8479] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  589.338060][ T8479] Call Trace:
[  589.338178][ T8479]  <TASK>
[ 589.338257][ T8479] dump_stack_lvl (lib/dump_stack.c:123)
[ 589.338419][ T8479] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 589.338574][ T8479] validate_chain (kernel/locking/lockdep.c:3894)
[ 589.338726][ T8479] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 589.338948][ T8479] ? 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)
[ 589.339119][ T8479] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 589.339238][ T8479] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 589.339389][ T8479] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 589.339552][ T8479] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 589.339804][ T8479] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 589.339996][ T8479] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 589.340187][ T8479] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 589.340361][ T8479] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 589.340513][ T8479] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 589.340753][ T8479] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 589.340872][ T8479] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 589.341125][ T8479] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 589.341281][ T8479] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406)
[ 589.341472][ T8479] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 589.341681][ T8479] __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))
[ 589.341832][ T8479] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 589.342030][ T8479] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 589.342239][ T8479] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359)
[ 589.342364][ T8479] ? 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)
[ 589.342515][ T8479] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 589.342717][ T8479] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 589.342910][ T8479] ? mutex_spin_on_owner (kernel/locking/mutex.c:332)
[ 589.343115][ T8479] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 589.343269][ T8479] ? nbp_backup_change (net/bridge/br_if.c:185 (discriminator 9))
[ 589.343426][ T8479] del_nbp (net/bridge/br_if.c:365)
[ 589.343543][ T8479] br_del_if (net/bridge/br_if.c:741)
[ 589.343661][ T8479] br_device_event (net/bridge/br.c:123)
[ 589.343811][ T8479] ? __pfx_br_device_event (net/bridge/br.c:29)
[ 589.343999][ T8479] ? packet_notifier (net/packet/af_packet.c:4282)
[ 589.344239][ T8479] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 589.344400][ T8479] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 589.344552][ T8479] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 589.344749][ T8479] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 589.344969][ T8479] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 589.345121][ T8479] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 589.345319][ T8479] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 589.345484][ T8479] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 589.345701][ T8479] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 589.345944][ T8479] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 589.346147][ T8479] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 589.346353][ T8479] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 589.346521][ T8479] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 589.346725][ T8479] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 589.346890][ T8479] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 589.347104][ T8479] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 589.347263][ T8479] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 589.347415][ T8479] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 589.347574][ T8479] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 589.347724][ T8479] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 589.347872][ T8479] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 589.348032][ T8479] ? 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)
[ 589.348187][ T8479] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 589.348305][ T8479] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 589.348473][ T8479] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 589.348654][ T8479] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 589.348866][ T8479] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 589.349033][ T8479] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 589.349184][ T8479] ? 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)
[ 589.349374][ T8479] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 589.349544][ T8479] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 589.349711][ T8479] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 589.349864][ T8479] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 589.350024][ T8479] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 589.350177][ T8479] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 589.350334][ T8479] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 589.350483][ T8479] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 589.350678][ T8479] ___sys_sendmsg (net/socket.c:2650)
[ 589.350838][ T8479] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 589.351037][ T8479] ? kasan_save_stack (mm/kasan/common.c:49)
[ 589.351223][ T8479] ? kasan_save_stack (mm/kasan/common.c:48)
[ 589.351371][ T8479] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 589.351520][ T8479] ? __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)
[ 589.351723][ T8479] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 589.351886][ T8479] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 589.352130][ T8479] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 589.352424][ T8479] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 589.352652][ T8479] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 589.352887][ T8479] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 589.353126][ T8479] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 589.353367][ T8479] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 589.353609][ T8479] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 589.353863][ T8479] __sys_sendmsg (net/socket.c:2680)
[ 589.354105][ T8479] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 589.354344][ T8479] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 589.354656][ T8479] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 589.354893][ T8479] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  589.355185][ T8479] RIP: 0033:0x7fc0e20289a7
[ 589.355439][ T8479] 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)
[  589.356291][ T8479] RSP: 002b:00007ffc19566188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  589.356660][ T8479] RAX: ffffffffffffffda RBX: 00007ffc195668c0 RCX: 00007fc0e20289a7
[  589.357023][ T8479] RDX: 0000000000000000 RSI: 00007ffc195661f0 RDI: 0000000000000005
[  589.357376][ T8479] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[  589.357724][ T8479] R10: 00007fc0e1ee64a8 R11: 0000000000000246 R12: 0000000000000001


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