======================================
| [4350.792280][T19436] #0: ffffffffb0007e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink (net/core/rtnetlink.c:3512)
| [4350.792547][T19436] #1: ffffffffafff6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [ 4350.792839][T19436]
| [ 4350.792839][T19436] stack backtrace:
[ 4350.793245][T19436] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 4350.793427][T19436] Call Trace:
[ 4350.793546][T19436]  <TASK>
[4350.793623][T19436] dump_stack_lvl (lib/dump_stack.c:123)
[4350.793773][T19436] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[4350.793919][T19436] validate_chain (kernel/locking/lockdep.c:3894)
[4350.794070][T19436] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[4350.794222][T19436] ? 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)
[4350.794366][T19436] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[4350.794476][T19436] __lock_acquire (kernel/locking/lockdep.c:5226)
[4350.794624][T19436] ? spin_bug (./include/linux/pid.h:232 kernel/locking/spinlock_debug.c:64 kernel/locking/spinlock_debug.c:78)
[4350.794735][T19436] ? debug_object_assert_init (./include/linux/err.h:81 lib/debugobjects.c:1010)
[4350.794883][T19436] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[4350.795028][T19436] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[4350.795208][T19436] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[4350.795355][T19436] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[4350.795500][T19436] ? lock_acquire (kernel/locking/lockdep.c:5822)
[4350.795648][T19436] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[4350.795826][T19436] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[4350.795937][T19436] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[4350.796117][T19436] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[4350.796262][T19436] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[4350.796406][T19436] __dev_close_many (net/core/dev.c:1537 (discriminator 3))
[4350.796553][T19436] ? __pfx___dev_close_many (net/core/dev.c:1525)
[4350.796702][T19436] dev_close_many (net/core/dev.c:1588)
[4350.796848][T19436] ? __pfx_dev_close_many (net/core/dev.c:1578)
[4350.796992][T19436] ? ipv6_mc_down (net/ipv6/mcast.c:1140 net/ipv6/mcast.c:2777)
[4350.797140][T19436] vlan_device_event (net/8021q/vlan.c:451)
[4350.797288][T19436] ? __pfx_vlan_device_event (net/8021q/vlan.c:362)
[4350.797431][T19436] ? __pfx_br_device_event (net/bridge/br.c:29)
[4350.797580][T19436] ? packet_notifier (net/packet/af_packet.c:4282)
[4350.797728][T19436] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[4350.797874][T19436] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[4350.798017][T19436] dev_close_many (net/core/dev.c:1591)
[4350.798159][T19436] ? find_held_lock (kernel/locking/lockdep.c:5339)
[4350.798303][T19436] ? __pfx_dev_close_many (net/core/dev.c:1578)
[4350.798448][T19436] ? __lock_release (kernel/locking/lockdep.c:5525)
[4350.798591][T19436] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[4350.798736][T19436] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[4350.798883][T19436] unregister_netdevice_many_notify (net/core/dev.c:11545)
[4350.799061][T19436] ? 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)
[4350.799205][T19436] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[4350.799315][T19436] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11512)
[4350.799494][T19436] ? __pfx_kernfs_free_rcu (fs/kernfs/dir.c:533)
[4350.799639][T19436] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[4350.799822][T19436] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3189 kernel/locking/mutex.h:47 kernel/locking/mutex.c:66)
[4350.799968][T19436] ? rtnl_is_locked (net/core/rtnetlink.c:164)
[4350.800112][T19436] ? unregister_netdevice_queue (net/core/dev.c:11497)
[4350.800289][T19436] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11496)
[4350.800466][T19436] ? br_dev_delete (net/bridge/br_if.c:396)
[4350.800612][T19436] rtnl_dellink (net/core/rtnetlink.c:3478 net/core/rtnetlink.c:3518)
[4350.800758][T19436] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3484)
[4350.800922][T19436] ? find_held_lock (kernel/locking/lockdep.c:5339)
[4350.801065][T19436] ? __lock_release (kernel/locking/lockdep.c:5525)
[4350.801209][T19436] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[4350.801352][T19436] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[4350.801494][T19436] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[4350.801642][T19436] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[4350.801788][T19436] ? __pfx_rtnl_dellink (net/core/rtnetlink.c:3484)
[4350.801941][T19436] rtnetlink_rcv_msg (net/core/rtnetlink.c:6902)
[4350.802085][T19436] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[4350.802232][T19436] ? 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)
[4350.802375][T19436] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[4350.802487][T19436] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[4350.802634][T19436] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[4350.802781][T19436] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[4350.802930][T19436] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[4350.803082][T19436] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[4350.803228][T19436] ? 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)
[4350.803372][T19436] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[4350.803518][T19436] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[4350.803752][T19436] ? find_held_lock (kernel/locking/lockdep.c:5339)
[4350.803899][T19436] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[4350.804043][T19436] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[4350.804196][T19436] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[4350.804425][T19436] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[4350.804568][T19436] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[4350.804750][T19436] ___sys_sendmsg (net/socket.c:2650)
[4350.804893][T19436] ? __pfx____sys_sendmsg (net/socket.c:2637)
[4350.805121][T19436] ? kasan_save_stack (mm/kasan/common.c:49)
[4350.805267][T19436] ? kasan_save_stack (mm/kasan/common.c:48)
[4350.805413][T19436] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[4350.805567][T19436] ? __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)
[4350.805833][T19436] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[4350.805983][T19436] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[4350.806130][T19436] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[4350.806309][T19436] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[4350.806537][T19436] ? find_held_lock (kernel/locking/lockdep.c:5339)
[4350.806685][T19436] ? __lock_release (kernel/locking/lockdep.c:5525)
[4350.806831][T19436] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[4350.806978][T19436] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[4350.807206][T19436] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[4350.807350][T19436] __sys_sendmsg (net/socket.c:2680)
[4350.807494][T19436] ? __pfx___sys_sendmsg (net/socket.c:2665)
[4350.807637][T19436] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[4350.807911][T19436] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[4350.808054][T19436] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 4350.808229][T19436] RIP: 0033:0x7f9cd3c0d9a7
[ 4350.808468][T19436] 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)
[ 4350.808974][T19436] RSP: 002b:00007ffcc1270a28 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 4350.809279][T19436] RAX: ffffffffffffffda RBX: 00007ffcc1271150 RCX: 00007f9cd3c0d9a7
[ 4350.809495][T19436] RDX: 0000000000000000 RSI: 00007ffcc1270a90 RDI: 0000000000000005
[ 4350.809796][T19436] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[ 4350.810008][T19436] R10: 00007f9cd3acbef8 R11: 0000000000000246 R12: 0000000000000001


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