unregister_netdevice: waiting for netdevsim3 to become free. Usage count = 2
leaked reference.
 __netdev_tracker_alloc include/linux/netdevice.h:4021 [inline]
 netdev_tracker_alloc include/linux/netdevice.h:4033 [inline]
 fib6_nh_init+0x640/0x1ca0 net/ipv6/route.c:3626
 ip6_route_info_create+0x7ac/0xf14 net/ipv6/route.c:3804
 addrconf_f6i_alloc+0x2c0/0x5cc net/ipv6/route.c:4579
 ipv6_add_addr+0x3d0/0xc9c net/ipv6/addrconf.c:1121
 addrconf_add_linklocal+0x264/0x854 net/ipv6/addrconf.c:3242
 addrconf_addr_gen+0x3a8/0x930 net/ipv6/addrconf.c:3373
 addrconf_init_auto_addrs+0x794/0xc9c
 addrconf_notify+0x7d0/0xc94 net/ipv6/addrconf.c:3669
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
 __dev_notify_flags+0x2ac/0x534
 dev_change_flags+0xc8/0x154 net/core/dev.c:8669
 do_setlink+0xacc/0x3318 net/core/rtnetlink.c:2830
 __rtnl_newlink net/core/rtnetlink.c:3605 [inline]
 rtnl_newlink+0x1424/0x1b74 net/core/rtnetlink.c:3652
 rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6150
 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2508
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168