unregister_netdevice: waiting for lo to become free. Usage count = 2
ref_tracker: lo@ffff8880608785b8 has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4110 [inline]
     netdev_hold include/linux/netdevice.h:4139 [inline]
     dst_init+0xd9/0x460 net/core/dst.c:52
     dst_alloc+0x12e/0x170 net/core/dst.c:93
     rt_dst_alloc net/ipv4/route.c:1662 [inline]
     __mkroute_output net/ipv4/route.c:2626 [inline]
     ip_route_output_key_hash_rcu+0x14f0/0x2360 net/ipv4/route.c:2848
     ip_route_output_key_hash+0x1f3/0x330 net/ipv4/route.c:2677
     __ip_route_output_key include/net/route.h:134 [inline]
     ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2905
     ip_route_output_ports include/net/route.h:177 [inline]
     inet_sk_rebuild_header+0xa1a/0x1c20 net/ipv4/af_inet.c:1327
     __tcp_retransmit_skb+0x24f/0x1500 net/ipv4/tcp_output.c:3297
     tcp_retransmit_skb+0x32/0x360 net/ipv4/tcp_output.c:3396
     tcp_retransmit_timer+0x19e9/0x3020 net/ipv4/tcp_timer.c:603
     tcp_write_timer+0x12a/0x280 net/ipv4/tcp_timer.c:709
     call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
     expire_timers kernel/time/timer.c:1752 [inline]
     __run_timers+0x542/0x800 kernel/time/timer.c:2023
     run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
     handle_softirqs+0x280/0x820 kernel/softirq.c:578
     __do_softirq kernel/softirq.c:612 [inline]
     invoke_softirq kernel/softirq.c:452 [inline]
     __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
     irq_exit_rcu+0x9/0x20 kernel/softirq.c:673