======================================
| [ 30.046641][ T373] #0: ffffffffbd5f1088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3521)
| [ 30.046927][ T373] #1: ffffffffbd5dfc30 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   30.047240][  T373]
| [   30.047240][  T373] stack backtrace:
[   30.047662][  T373] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   30.047862][  T373] Call Trace:
[   30.047982][  T373]  <TASK>
[ 30.048062][ T373] dump_stack_lvl (lib/dump_stack.c:123)
[ 30.048220][ T373] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 30.048376][ T373] validate_chain (kernel/locking/lockdep.c:3894)
[ 30.048535][ T373] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 30.048693][ T373] ? 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)
[ 30.048849][ T373] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 30.048975][ T373] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 30.049133][ T373] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 30.049290][ T373] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 30.049485][ T373] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 30.049640][ T373] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 30.049798][ T373] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 30.049956][ T373] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 30.050155][ T373] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 30.050274][ T373] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 30.050467][ T373] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 30.050622][ T373] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 30.050778][ T373] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 30.050941][ T373] __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))
[ 30.051099][ T373] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 30.051297][ T373] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 30.051454][ T373] ? del_nbp (net/bridge/br_if.c:215 net/bridge/br_if.c:359) bridge
[ 30.051657][ T373] ? 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)
[ 30.051814][ T373] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 30.051976][ T373] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 30.052167][ T373] ? mutex_spin_on_owner (kernel/locking/mutex.c:353)
[ 30.052326][ T373] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 30.052492][ T373] del_nbp (net/bridge/br_if.c:365) bridge
[ 30.052683][ T373] br_del_if (net/bridge/br_if.c:741) bridge
[ 30.052901][ T373] br_device_event (net/bridge/br.c:141) bridge
[ 30.053088][ T373] ? __pfx_br_device_event (net/bridge/br.c:29) bridge
[ 30.053313][ T373] ? 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
[ 30.053484][ T373] ? packet_notifier (net/packet/af_packet.c:4282)
[ 30.053641][ T373] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 30.053805][ T373] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 30.053964][ T373] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 30.054158][ T373] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 30.054353][ T373] ? rtnl_dellink (net/core/rtnetlink.c:3521)
[ 30.054508][ T373] ? sock_def_readable (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock.c:3479)
[ 30.054666][ T373] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 30.054821][ T373] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 30.055022][ T373] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 30.055214][ T373] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 30.055406][ T373] rtnl_dellink (net/core/rtnetlink.c:3487 net/core/rtnetlink.c:3527)
[ 30.055564][ T373] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 30.055738][ T373] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 30.055899][ T373] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 30.056052][ T373] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 30.056214][ T373] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 30.056369][ T373] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 30.056532][ T373] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6909)
[ 30.056688][ T373] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3493)
[ 30.056847][ T373] rtnetlink_rcv_msg (net/core/rtnetlink.c:6911)
[ 30.057005][ T373] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 30.057158][ T373] ? 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)
[ 30.057317][ T373] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 30.057435][ T373] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 30.057596][ T373] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 30.057753][ T373] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6814)
[ 30.057911][ T373] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 30.058069][ T373] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 30.058226][ T373] ? 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)
[ 30.058384][ T373] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 30.058539][ T373] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 30.058692][ T373] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 30.058850][ T373] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 30.059011][ T373] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 30.059166][ T373] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 30.059320][ T373] ? _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)
[ 30.059478][ T373] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 30.059637][ T373] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 30.059791][ T373] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 30.059997][ T373] ___sys_sendmsg (net/socket.c:2650)
[ 30.060152][ T373] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 30.060306][ T373] ? kasan_save_stack (mm/kasan/common.c:49)
[ 30.060465][ T373] ? kasan_save_stack (mm/kasan/common.c:48)
[ 30.060622][ T373] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 30.060783][ T373] ? __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)
[ 30.060981][ T373] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 30.061139][ T373] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 30.061296][ T373] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 30.061486][ T373] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 30.061644][ T373] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 30.061800][ T373] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 30.061966][ T373] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 30.062120][ T373] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 30.062274][ T373] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 30.062431][ T373] __sys_sendmsg (net/socket.c:2680)
[ 30.062585][ T373] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 30.062740][ T373] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 30.062958][ T373] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 30.063122][ T373] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   30.063315][  T373] RIP: 0033:0x7f8ada5039a7
[ 30.063478][ T373] 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)
[   30.064028][  T373] RSP: 002b:00007fff1d6e2898 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   30.064263][  T373] RAX: ffffffffffffffda RBX: 00007fff1d6e2fc0 RCX: 00007f8ada5039a7
[   30.064498][  T373] RDX: 0000000000000000 RSI: 00007fff1d6e2900 RDI: 0000000000000005
[   30.064729][  T373] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[   30.064967][  T373] R10: 00007f8ada3c1ef8 R11: 0000000000000246 R12: 0000000000000001


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