unregister_netdevice: waiting for lo to become free. Usage count = 2
leaked reference.
 __netdev_tracker_alloc include/linux/netdevice.h:4051 [inline]
 netdev_hold include/linux/netdevice.h:4080 [inline]
 dst_init+0xda/0x410 net/core/dst.c:52
 dst_alloc+0x12a/0x160 net/core/dst.c:92
 rt_dst_alloc net/ipv4/route.c:1662 [inline]
 __mkroute_output net/ipv4/route.c:2628 [inline]
 ip_route_output_key_hash_rcu+0x14a4/0x23f0 net/ipv4/route.c:2850
 ip_route_output_key_hash+0x1ef/0x330 net/ipv4/route.c:2679
 __ip_route_output_key include/net/route.h:137 [inline]
 ip_route_output_flow+0x26/0x150 net/ipv4/route.c:2909
 ip_route_connect include/net/route.h:331 [inline]
 tcp_v4_connect+0x797/0x18e0 net/ipv4/tcp_ipv4.c:243
 __inet_stream_connect+0x242/0xe10 net/ipv4/af_inet.c:668
 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:739
 kernel_connect+0x13e/0x1c0 net/socket.c:3554
 rds_tcp_conn_path_connect+0x548/0x6b0 net/rds/tcp_connect.c:176
 rds_connect_worker+0x1ce/0x280 net/rds/threads.c:176
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295