unregister_netdevice: waiting for lo to become free. Usage count = 2
ref_tracker: lo@ffff88802fff45b8 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]
     ip_route_input_slow net/ipv4/route.c:2400 [inline]
     ip_route_input_rcu+0x200f/0x30e0 net/ipv4/route.c:2514
     ip_route_input_noref+0x184/0x270 net/ipv4/route.c:2525
     ip_rcv_finish_core+0x5a6/0x1bc0 net/ipv4/ip_input.c:365
     ip_rcv_finish+0x14e/0x250 net/ipv4/ip_input.c:447
     NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
     __netif_receive_skb_one_core net/core/dev.c:5638 [inline]
     __netif_receive_skb+0xcc/0x290 net/core/dev.c:5752
     netif_receive_skb_internal net/core/dev.c:5838 [inline]
     netif_receive_skb+0x1bc/0x720 net/core/dev.c:5897
     tun_rx_batched+0x1df/0x790 drivers/net/tun.c:1556
     tun_get_user+0x28a3/0x3ca0 drivers/net/tun.c:2009
     tun_chr_write_iter+0x119/0x200 drivers/net/tun.c:2055
     call_write_iter include/linux/fs.h:2018 [inline]
     new_sync_write fs/read_write.c:491 [inline]
     vfs_write+0x46c/0x990 fs/read_write.c:584
     ksys_write+0x150/0x260 fs/read_write.c:637
     do_syscall_x64 arch/x86/entry/common.c:46 [inline]
     do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
     entry_SYSCALL_64_after_hwframe+0x68/0xd2