unregister_netdevice: waiting for lo to become free. Usage count = 2
ref_tracker: netdev@ffff888036892620 has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4403 [inline]
     netdev_hold include/linux/netdevice.h:4432 [inline]
     dst_init+0xd9/0x480 net/core/dst.c:52
     dst_alloc+0x12a/0x170 net/core/dst.c:94
     rt_dst_alloc net/ipv4/route.c:1651 [inline]
     __mkroute_output net/ipv4/route.c:2655 [inline]
     ip_route_output_key_hash_rcu+0x14d0/0x25d0 net/ipv4/route.c:2875
     ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2705
     __ip_route_output_key include/net/route.h:169 [inline]
     ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2932
     inet_sk_rebuild_header+0x915/0x1da0 net/ipv4/af_inet.c:1330
     __tcp_retransmit_skb+0x254/0x1640 net/ipv4/tcp_output.c:3606
     tcp_retransmit_skb+0x33/0x440 net/ipv4/tcp_output.c:3719
     tcp_retransmit_timer+0x1ac7/0x35f0 net/ipv4/tcp_timer.c:630
     tcp_write_timer+0x15c/0x2d0 net/ipv4/tcp_timer.c:739
     call_timer_fn+0x192/0x640 kernel/time/timer.c:1748
     expire_timers kernel/time/timer.c:1799 [inline]
     __run_timers kernel/time/timer.c:2373 [inline]
     __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
     run_timer_base kernel/time/timer.c:2394 [inline]
     run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
     handle_softirqs+0x22a/0x870 kernel/softirq.c:622
     __do_softirq kernel/softirq.c:656 [inline]
     invoke_softirq kernel/softirq.c:496 [inline]
     __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
     irq_exit_rcu+0x9/0x30 kernel/softirq.c:739