======================================
| [ 3126.886053][   T75] veth_A-C (unregistering): left promiscuous mode
| [ 3138.746264][T14782] geneve_a: left promiscuous mode
| [ 3143.614591][T14796] ovs_br0: left promiscuous mode
| [ 3974.843646][T19297] Initializing XFRM netlink socket
| [ 4448.921111][T21690] unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 5
[ 4448.921641][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 2/4 users at
[4448.921641][T21690] dst_init (net/core/dst.c:53) 
[4448.921641][T21690] dst_alloc (net/core/dst.c:96) 
[4448.921641][T21690] ip6_dst_alloc (net/ipv6/route.c:342) 
[4448.921641][T21690] ip6_rt_pcpu_alloc (net/ipv6/route.c:1381) 
[4448.921641][T21690] ip6_pol_route (net/ipv6/route.c:1430 net/ipv6/route.c:2267) 
[4448.921641][T21690] fib6_rule_lookup (./include/net/ip6_fib.h:616 net/ipv6/fib6_rules.c:121) 
[4448.921641][T21690] ip6_route_output_flags (net/ipv6/route.c:2639 net/ipv6/route.c:2651) 
[4448.921641][T21690] ip6_dst_lookup_tail.constprop.0 (net/ipv6/ip6_output.c:1156) 
[4448.921641][T21690] ip6_dst_lookup_flow (net/ipv6/ip6_output.c:1260) 
[4448.921641][T21690] udp_tunnel6_dst_lookup (net/ipv6/ip6_udp_tunnel.c:165 net/ipv6/ip6_udp_tunnel.c:135) 
[4448.921641][T21690] vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2530 (discriminator 4)) vxlan
[4448.921641][T21690] vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2795) vxlan
[4448.921641][T21690] dev_hard_start_xmit (./include/linux/netdevice.h:4889 ./include/linux/netdevice.h:4898 net/core/dev.c:3582 net/core/dev.c:3598) 
[4448.921641][T21690] __dev_queue_xmit (net/core/dev.h:168 net/core/dev.c:4426) 
[4448.921641][T21690] ip6_finish_output2 (./include/net/neighbour.h:540 net/ipv6/ip6_output.c:141) 
[4448.921641][T21690] ip6_finish_output (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226) 
| [4448.921641][T21690] dev_hard_start_xmit (./include/linux/netdevice.h:4889 ./include/linux/netdevice.h:4898 net/core/dev.c:3582 net/core/dev.c:3598) 
| [4448.921641][T21690] __dev_queue_xmit (net/core/dev.h:168 net/core/dev.c:4426) 
| [4448.921641][T21690] ip6_finish_output2 (./include/net/neighbour.h:540 net/ipv6/ip6_output.c:141) 
| [4448.921641][T21690] ip6_finish_output (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226) 
| [ 4448.921641][T21690]
[ 4448.924548][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 1/4 users at
[4448.924548][T21690] netdev_get_by_index (net/core/dev.c:917) 
[4448.924548][T21690] fib6_nh_init (net/ipv6/route.c:3543) 
[4448.924548][T21690] nh_create_ipv6 (net/ipv4/nexthop.c:2841) 
[4448.924548][T21690] nexthop_create (net/ipv4/nexthop.c:2892) 
[4448.924548][T21690] rtm_new_nexthop (net/ipv4/nexthop.c:2934 net/ipv4/nexthop.c:3220) 
[4448.924548][T21690] rtnetlink_rcv_msg (net/core/rtnetlink.c:6650) 
[4448.924548][T21690] netlink_rcv_skb (net/netlink/af_netlink.c:2550) 
[4448.924548][T21690] netlink_unicast (net/netlink/af_netlink.c:1331 net/netlink/af_netlink.c:1357) 
[4448.924548][T21690] netlink_sendmsg (net/netlink/af_netlink.c:1901) 
[4448.924548][T21690] ____sys_sendmsg (net/socket.c:730 net/socket.c:745 net/socket.c:2602) 
[4448.924548][T21690] ___sys_sendmsg (net/socket.c:2658) 
[4448.924548][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
[4448.924548][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[4448.924548][T21690] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
| [4448.924548][T21690] ___sys_sendmsg (net/socket.c:2658) 
| [4448.924548][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
| [4448.924548][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
| [4448.924548][T21690] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
| [ 4448.924548][T21690]
[ 4448.926522][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 1/4 users at
[4448.926522][T21690] ipv6_add_dev (net/ipv6/addrconf.c:344 net/ipv6/addrconf.c:409) 
[4448.926522][T21690] addrconf_notify (net/ipv6/addrconf.c:3656) 
[4448.926522][T21690] notifier_call_chain (kernel/notifier.c:93 (discriminator 2)) 
[4448.926522][T21690] register_netdevice (./include/linux/notifier.h:207 net/core/dev.c:10500) 
[4448.926522][T21690] veth_newlink (drivers/net/veth.c:1861) 
[4448.926522][T21690] rtnl_newlink_create (net/core/rtnetlink.c:3514) 
[4448.926522][T21690] __rtnl_newlink (net/core/rtnetlink.c:3734) 
[4448.926522][T21690] rtnl_newlink (net/core/rtnetlink.c:3748) 
[4448.926522][T21690] rtnetlink_rcv_msg (net/core/rtnetlink.c:6650) 
[4448.926522][T21690] netlink_rcv_skb (net/netlink/af_netlink.c:2550) 
[4448.926522][T21690] netlink_unicast (net/netlink/af_netlink.c:1331 net/netlink/af_netlink.c:1357) 
[4448.926522][T21690] netlink_sendmsg (net/netlink/af_netlink.c:1901) 
[4448.926522][T21690] ____sys_sendmsg (net/socket.c:730 net/socket.c:745 net/socket.c:2602) 
[4448.926522][T21690] ___sys_sendmsg (net/socket.c:2658) 
[4448.926522][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
[4448.926522][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
| [4448.926522][T21690] ___sys_sendmsg (net/socket.c:2658) 
| [4448.926522][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
| [4448.926522][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
| [ 4448.926522][T21690]
| [ 4459.143080][T21690] unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 5
[ 4459.143494][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 2/4 users at
[4459.143494][T21690] dst_init (net/core/dst.c:53) 
[4459.143494][T21690] dst_alloc (net/core/dst.c:96) 
[4459.143494][T21690] ip6_dst_alloc (net/ipv6/route.c:342) 
[4459.143494][T21690] ip6_rt_pcpu_alloc (net/ipv6/route.c:1381) 
[4459.143494][T21690] ip6_pol_route (net/ipv6/route.c:1430 net/ipv6/route.c:2267) 
[4459.143494][T21690] fib6_rule_lookup (./include/net/ip6_fib.h:616 net/ipv6/fib6_rules.c:121) 
[4459.143494][T21690] ip6_route_output_flags (net/ipv6/route.c:2639 net/ipv6/route.c:2651) 
[4459.143494][T21690] ip6_dst_lookup_tail.constprop.0 (net/ipv6/ip6_output.c:1156) 
[4459.143494][T21690] ip6_dst_lookup_flow (net/ipv6/ip6_output.c:1260) 
[4459.143494][T21690] udp_tunnel6_dst_lookup (net/ipv6/ip6_udp_tunnel.c:165 net/ipv6/ip6_udp_tunnel.c:135) 
[4459.143494][T21690] vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2530 (discriminator 4)) vxlan
[4459.143494][T21690] vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2795) vxlan
[4459.143494][T21690] dev_hard_start_xmit (./include/linux/netdevice.h:4889 ./include/linux/netdevice.h:4898 net/core/dev.c:3582 net/core/dev.c:3598) 
[4459.143494][T21690] __dev_queue_xmit (net/core/dev.h:168 net/core/dev.c:4426) 
[4459.143494][T21690] ip6_finish_output2 (./include/net/neighbour.h:540 net/ipv6/ip6_output.c:141) 
[4459.143494][T21690] ip6_finish_output (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226) 
| [4459.143494][T21690] dev_hard_start_xmit (./include/linux/netdevice.h:4889 ./include/linux/netdevice.h:4898 net/core/dev.c:3582 net/core/dev.c:3598) 
| [4459.143494][T21690] __dev_queue_xmit (net/core/dev.h:168 net/core/dev.c:4426) 
| [4459.143494][T21690] ip6_finish_output2 (./include/net/neighbour.h:540 net/ipv6/ip6_output.c:141) 
| [4459.143494][T21690] ip6_finish_output (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226) 
| [ 4459.143494][T21690]
[ 4459.146078][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 1/4 users at
[4459.146078][T21690] netdev_get_by_index (net/core/dev.c:917) 
[4459.146078][T21690] fib6_nh_init (net/ipv6/route.c:3543) 
[4459.146078][T21690] nh_create_ipv6 (net/ipv4/nexthop.c:2841) 
[4459.146078][T21690] nexthop_create (net/ipv4/nexthop.c:2892) 
[4459.146078][T21690] rtm_new_nexthop (net/ipv4/nexthop.c:2934 net/ipv4/nexthop.c:3220) 
[4459.146078][T21690] rtnetlink_rcv_msg (net/core/rtnetlink.c:6650) 
[4459.146078][T21690] netlink_rcv_skb (net/netlink/af_netlink.c:2550) 
[4459.146078][T21690] netlink_unicast (net/netlink/af_netlink.c:1331 net/netlink/af_netlink.c:1357) 
[4459.146078][T21690] netlink_sendmsg (net/netlink/af_netlink.c:1901) 
[4459.146078][T21690] ____sys_sendmsg (net/socket.c:730 net/socket.c:745 net/socket.c:2602) 
[4459.146078][T21690] ___sys_sendmsg (net/socket.c:2658) 
[4459.146078][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
[4459.146078][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[4459.146078][T21690] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
| [4459.146078][T21690] ___sys_sendmsg (net/socket.c:2658) 
| [4459.146078][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 
| [4459.146078][T21690] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
| [4459.146078][T21690] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
| [ 4459.146078][T21690]
[ 4459.148293][T21690] ref_tracker: veth_A-R1@ffff88800d9c15e0 has 1/4 users at
[4459.148293][T21690] ipv6_add_dev (net/ipv6/addrconf.c:344 net/ipv6/addrconf.c:409) 
[4459.148293][T21690] addrconf_notify (net/ipv6/addrconf.c:3656) 
[4459.148293][T21690] notifier_call_chain (kernel/notifier.c:93 (discriminator 2)) 
[4459.148293][T21690] register_netdevice (./include/linux/notifier.h:207 net/core/dev.c:10500) 
[4459.148293][T21690] veth_newlink (drivers/net/veth.c:1861) 
[4459.148293][T21690] rtnl_newlink_create (net/core/rtnetlink.c:3514) 
[4459.148293][T21690] __rtnl_newlink (net/core/rtnetlink.c:3734) 
[4459.148293][T21690] rtnl_newlink (net/core/rtnetlink.c:3748) 
[4459.148293][T21690] rtnetlink_rcv_msg (net/core/rtnetlink.c:6650) 
[4459.148293][T21690] netlink_rcv_skb (net/netlink/af_netlink.c:2550) 
[4459.148293][T21690] netlink_unicast (net/netlink/af_netlink.c:1331 net/netlink/af_netlink.c:1357) 
[4459.148293][T21690] netlink_sendmsg (net/netlink/af_netlink.c:1901) 
[4459.148293][T21690] ____sys_sendmsg (net/socket.c:730 net/socket.c:745 net/socket.c:2602) 
[4459.148293][T21690] ___sys_sendmsg (net/socket.c:2658) 
[4459.148293][T21690] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2687) 


Finger prints:
dev_hard_start_xmit:__dev_queue_xmit:ip6_finish_output2:ip6_finish_output:netdev_get_by_index
dst_init:dst_alloc:ip6_dst_alloc:ip6_rt_pcpu_alloc:ip6_pol_route
___sys_sendmsg:__sys_sendmsg:do_syscall_64:dst_init:dst_alloc
___sys_sendmsg:__sys_sendmsg:do_syscall_64:ipv6_add_dev:addrconf_notify