======================================
| [ 121.353772][ T2908] #1: ffffffffb6807e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink (net/core/rtnetlink.c:328 net/core/rtnetlink.c:4011)
| [ 121.354056][ T2908] #2: ffffffffb67f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  121.354359][ T2908]
| [  121.354359][ T2908] stack backtrace:
[  121.354772][ T2908] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  121.354961][ T2908] Call Trace:
[  121.355075][ T2908]  <TASK>
[ 121.355154][ T2908] dump_stack_lvl (lib/dump_stack.c:123)
[ 121.355309][ T2908] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 121.355462][ T2908] validate_chain (kernel/locking/lockdep.c:3894)
[ 121.355616][ T2908] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 121.355774][ T2908] ? 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)
[ 121.355926][ T2908] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 121.356066][ T2908] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 121.356223][ T2908] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 121.356378][ T2908] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 121.356572][ T2908] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 121.356728][ T2908] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 121.356889][ T2908] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 121.357044][ T2908] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 121.357238][ T2908] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 121.357358][ T2908] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 121.357550][ T2908] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 121.357706][ T2908] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 121.357862][ T2908] netdev_update_features (net/core/dev.c:10314)
[ 121.358032][ T2908] ? __pfx_netdev_update_features (net/core/dev.c:10311)
[ 121.358220][ T2908] vlan_device_event (net/8021q/vlan.c:430 (discriminator 2))
[ 121.358374][ T2908] ? __pfx_vlan_device_event (net/8021q/vlan.c:362)
[ 121.358526][ T2908] ? __pfx_br_device_event (net/bridge/br.c:29)
[ 121.358677][ T2908] ? packet_notifier (net/packet/af_packet.c:4282)
[ 121.358826][ T2908] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 121.358976][ T2908] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 121.359134][ T2908] netdev_update_features (net/core/dev.c:10314)
[ 121.359284][ T2908] ? __pfx_netdev_update_features (net/core/dev.c:10311)
[ 121.359469][ T2908] br_add_if (net/bridge/br_if.c:657)
[ 121.359582][ T2908] ? rtnl_is_locked (net/core/rtnetlink.c:164)
[ 121.359732][ T2908] ? netdev_master_upper_dev_get (net/core/dev.c:7230)
[ 121.359919][ T2908] rtnl_newlink_create (net/core/rtnetlink.c:3804)
[ 121.360067][ T2908] ? __pfx_rtnl_newlink_create (net/core/rtnetlink.c:3753)
[ 121.360221][ T2908] ? rtnl_newlink (net/core/rtnetlink.c:328 net/core/rtnetlink.c:4011)
[ 121.360370][ T2908] ? __pfx___mutex_lock (kernel/locking/mutex.c:734)
[ 121.360518][ T2908] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 121.360669][ T2908] __rtnl_newlink (net/core/rtnetlink.c:3897)
[ 121.360838][ T2908] rtnl_newlink (net/core/rtnetlink.c:336 net/core/rtnetlink.c:4013)
[ 121.360994][ T2908] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3903)
[ 121.361151][ T2908] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 121.361305][ T2908] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 121.361472][ T2908] ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/rtnetlink.c:6900)
[ 121.361627][ T2908] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3903)
[ 121.361781][ T2908] rtnetlink_rcv_msg (net/core/rtnetlink.c:6902)
[ 121.361935][ T2908] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 121.362090][ T2908] ? 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)
[ 121.362249][ T2908] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 121.362366][ T2908] ? __lock_acquire (kernel/locking/lockdep.c:5226)
[ 121.362524][ T2908] netlink_rcv_skb (net/netlink/af_netlink.c:2543)
[ 121.362678][ T2908] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6805)
[ 121.362845][ T2908] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2520)
[ 121.362998][ T2908] ? netlink_deliver_tap (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/netlink/af_netlink.c:340)
[ 121.363151][ T2908] ? 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)
[ 121.363298][ T2908] netlink_unicast (net/netlink/af_netlink.c:1322 net/netlink/af_netlink.c:1348)
[ 121.363450][ T2908] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1333)
[ 121.363602][ T2908] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 121.363750][ T2908] netlink_sendmsg (net/netlink/af_netlink.c:1892)
[ 121.363898][ T2908] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1811)
[ 121.364053][ T2908] ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2594)
[ 121.364210][ T2908] ? __pfx_____sys_sendmsg (net/socket.c:2540)
[ 121.364358][ T2908] ? __pfx_copy_msghdr_from_user (net/socket.c:2520)
[ 121.364545][ T2908] ___sys_sendmsg (net/socket.c:2650)
[ 121.364699][ T2908] ? __pfx____sys_sendmsg (net/socket.c:2637)
[ 121.364863][ T2908] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 121.365017][ T2908] ? __pfx_handle_pte_fault (mm/memory.c:5758)
[ 121.365187][ T2908] ? __handle_mm_fault (mm/memory.c:5944)
[ 121.365342][ T2908] ? __pfx___handle_mm_fault (mm/memory.c:5853)
[ 121.365556][ T2908] ? mt_find (lib/maple_tree.c:6949)
[ 121.365722][ T2908] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 121.365946][ T2908] ? __lock_release (kernel/locking/lockdep.c:5525)
[ 121.366132][ T2908] ? do_user_addr_fault (./include/linux/mmap_lock.h:172 arch/x86/mm/fault.c:1417)
[ 121.366287][ T2908] __sys_sendmsg (net/socket.c:2680)
[ 121.366444][ T2908] ? __pfx___sys_sendmsg (net/socket.c:2665)
[ 121.366599][ T2908] ? do_user_addr_fault (./include/linux/mmap_lock.h:172 arch/x86/mm/fault.c:1417)
[ 121.366777][ T2908] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
[ 121.366936][ T2908] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  121.367133][ T2908] RIP: 0033:0x7fdf654f49a7
[ 121.367307][ T2908] 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)
[  121.367850][ T2908] RSP: 002b:00007fff1b8b0928 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  121.368091][ T2908] RAX: ffffffffffffffda RBX: 00007fff1b8b1060 RCX: 00007fdf654f49a7
[  121.368320][ T2908] RDX: 0000000000000000 RSI: 00007fff1b8b0990 RDI: 0000000000000005
[  121.368544][ T2908] RBP: 0000000000000006 R08: 000000000000006c R09: 0000000000000000
[  121.368796][ T2908] R10: 00007fdf65543ac0 R11: 0000000000000246 R12: 00007fff1b8b1098


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