======================================
| [ 12.643803][ T300] #0: ffffffffb4207e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink (net/core/rtnetlink.c:328 net/core/rtnetlink.c:4011)
| [ 12.644115][ T300] #1: ffffffffb41f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   12.644435][  T300]
| [   12.644435][  T300] stack backtrace:
[   12.644870][  T300] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.645067][  T300] Call Trace:
[   12.645186][  T300]  <TASK>
[ 12.645269][ T300] dump_stack_lvl (lib/dump_stack.c:123)
[ 12.645431][ T300] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 12.645595][ T300] validate_chain (kernel/locking/lockdep.c:3894)
[ 12.645757][ T300] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 12.645917][ T300] ? 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)
[ 12.646076][ T300] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 12.646197][ T300] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 12.646359][ T300] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 12.646516][ T300] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 12.646715][ T300] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 12.646873][ T300] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 12.647032][ T300] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 12.647193][ T300] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 12.647393][ T300] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 12.647515][ T300] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 12.647713][ T300] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 12.647875][ T300] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 12.648036][ T300] netdev_update_features (net/core/dev.c:10314)
[ 12.648195][ T300] ? __pfx_netdev_update_features (net/core/dev.c:10311)
[ 12.648394][ T300] vlan_device_event (net/8021q/vlan.c:430 (discriminator 2))
[ 12.648556][ T300] ? __pfx_vlan_device_event (net/8021q/vlan.c:362)
[ 12.648714][ T300] ? __pfx_br_device_event (net/bridge/br.c:29)
[ 12.648877][ T300] ? packet_notifier (net/packet/af_packet.c:4282)
[ 12.649037][ T300] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 12.649197][ T300] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 12.649354][ T300] netdev_update_features (net/core/dev.c:10314)
[ 12.649511][ T300] ? __pfx_netdev_update_features (net/core/dev.c:10311)
[ 12.649711][ T300] br_add_if (net/bridge/br_if.c:657)
[ 12.649832][ T300] ? rtnl_is_locked (net/core/rtnetlink.c:164)
[ 12.649994][ T300] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 12.650190][ T300] do_setlink.constprop.0 (net/core/rtnetlink.c:3116)
[ 12.650348][ T300] ? __pfx_do_setlink.constprop.0 (net/core/rtnetlink.c:2990)
[ 12.650545][ T300] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 12.650702][ T300] ? rtnl_newlink (net/core/rtnetlink.c:328 net/core/rtnetlink.c:4011)
[ 12.650861][ T300] ? rtnl_newlink (./include/linux/slab.h:901 net/core/rtnetlink.c:3912)
[ 12.651016][ T300] ? rtnetlink_rcv_msg (net/core/rtnetlink.c:6902)
[ 12.651183][ T300] ? __mutex_trylock_common (./arch/x86/include/asm/atomic64_64.h:101 ./include/linux/atomic/atomic-arch-fallback.h:4296 ./include/linux/atomic/atomic-long.h:1482 ./include/linux/atomic/atomic-instrumented.h:4458 kernel/locking/mutex.c:104)
[ 12.651344][ T300] ? __pfx___mutex_trylock_common (kernel/locking/mutex.c:79)
[ 12.651541][ T300] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 12.651697][ T300] ? trace_contention_end (./include/trace/events/lock.h:122 (discriminator 37))
[ 12.651856][ T300] ? __mutex_lock (./arch/x86/include/asm/preempt.h:94 kernel/locking/mutex.c:595 kernel/locking/mutex.c:735)
[ 12.652014][ T300] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114)
[ 12.652171][ T300] ? rtnl_newlink (net/core/rtnetlink.c:328 net/core/rtnetlink.c:4011)
[ 12.652329][ T300] ? __pfx___mutex_lock (kernel/locking/mutex.c:734)
[ 12.652486][ T300] ? __rtnl_newlink (net/core/rtnetlink.c:3862)
[ 12.652643][ T300] rtnl_newlink (net/core/rtnetlink.c:336 net/core/rtnetlink.c:4013)
[ 12.652801][ T300] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3903)
[ 12.652955][ T300] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 12.653113][ T300] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 12.653268][ T300] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 12.653432][ T300] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[ 12.653589][ T300] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3903)
[ 12.653748][ T300] rtnetlink_rcv_msg (net/core/rtnetlink.c:6902)
[ 12.653907][ T300] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 12.654063][ T300] ? 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)
[ 12.654222][ T300] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 12.654344][ T300] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 12.654502][ T300] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 12.654666][ T300] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 12.654825][ T300] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 12.654987][ T300] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 12.655145][ T300] ? 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)
[ 12.655302][ T300] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 12.655464][ T300] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 12.655621][ T300] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 12.655782][ T300] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 12.655942][ T300] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 12.656102][ T300] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 12.656260][ T300] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 12.656416][ T300] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 12.656618][ T300] ___sys_sendmsg (net/socket.c:2650)
[ 12.656777][ T300] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 12.656938][ T300] ? kasan_save_stack (mm/kasan/common.c:49)
[ 12.657099][ T300] ? kasan_save_stack (mm/kasan/common.c:48)
[ 12.657257][ T300] ? __kasan_record_aux_stack (mm/kasan/generic.c:544)
[ 12.657415][ T300] ? __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)
[ 12.657612][ T300] ? __x64_sys_close (fs/open.c:1557 fs/open.c:1539 fs/open.c:1539)
[ 12.657770][ T300] ? do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 12.657928][ T300] ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 12.658127][ T300] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 12.658287][ T300] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 12.658443][ T300] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 12.658600][ T300] ? __virt_addr_valid (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:962 ./include/linux/mmzone.h:2058 arch/x86/mm/physaddr.c:65)
[ 12.658764][ T300] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 12.658919][ T300] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 12.659082][ T300] __sys_sendmsg (net/socket.c:2680)
[ 12.659240][ T300] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 12.659396][ T300] ? __pfx_slab_free_after_rcu_debug (mm/slub.c:4643)
[ 12.659598][ T300] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 12.659757][ T300] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   12.659951][  T300] RIP: 0033:0x7ff790b5c9a7
[ 12.660115][ T300] 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)
[   12.660674][  T300] RSP: 002b:00007fffdc7d2138 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   12.660912][  T300] RAX: ffffffffffffffda RBX: 00007fffdc7d2870 RCX: 00007ff790b5c9a7
[   12.661154][  T300] RDX: 0000000000000000 RSI: 00007fffdc7d21a0 RDI: 0000000000000005
[   12.661393][  T300] RBP: 0000000000000004 R08: 0000000000000003 R09: 0000000000000000
[   12.661630][  T300] R10: 000000000f8e1910 R11: 0000000000000246 R12: 0000000000000004


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