unregister_netdevice: waiting for lo to become free. Usage count = 2
ref_tracker: lo@8502934c has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4341 [inline]
     netdev_hold include/linux/netdevice.h:4370 [inline]
     dst_init+0x70/0x120 net/core/dst.c:52
     dst_alloc+0x5c/0x88 net/core/dst.c:93
     rt_dst_alloc+0x2c/0x84 net/ipv4/route.c:1642
     ip_route_input_slow+0x63c/0xb78 net/ipv4/route.c:2420
     ip_route_input_rcu net/ipv4/route.c:2534 [inline]
     ip_route_input_noref+0xa0/0xac net/ipv4/route.c:2545
     ip_rcv_finish_core+0x6c/0x5b4 net/ipv4/ip_input.c:364
     ip_rcv_finish+0x7c/0xb0 net/ipv4/ip_input.c:445
     NF_HOOK include/linux/netfilter.h:317 [inline]
     NF_HOOK include/linux/netfilter.h:311 [inline]
     ip_rcv+0xd4/0xe0 net/ipv4/ip_input.c:567
     __netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5977
     __netif_receive_skb+0x18/0x5c net/core/dev.c:6090
     netif_receive_skb_internal net/core/dev.c:6176 [inline]
     netif_receive_skb+0x3c/0x224 net/core/dev.c:6235
     tun_rx_batched drivers/net/tun.c:1485 [inline]
     tun_get_user+0xcf0/0x1098 drivers/net/tun.c:1938
     tun_chr_write_iter+0x60/0xc8 drivers/net/tun.c:1984
     new_sync_write fs/read_write.c:593 [inline]
     vfs_write+0x274/0x44c fs/read_write.c:686
     ksys_write+0x74/0xe8 fs/read_write.c:738
     __do_sys_write fs/read_write.c:749 [inline]
     sys_write+0x10/0x14 fs/read_write.c:746