unregister_netdevice: waiting for lo to become free. Usage count = 2
ref_tracker: lo@ffff88805fe885b8 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:1657 [inline]
     ip_route_input_slow net/ipv4/route.c:2395 [inline]
     ip_route_input_rcu+0x1f56/0x3010 net/ipv4/route.c:2509
     ip_route_input_noref+0x16f/0x260 net/ipv4/route.c:2520
     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+0x303/0x390 include/linux/netfilter.h:304
     __netif_receive_skb_one_core net/core/dev.c:5596 [inline]
     __netif_receive_skb+0xcc/0x290 net/core/dev.c:5710
     netif_receive_skb_internal net/core/dev.c:5796 [inline]
     netif_receive_skb+0x1bc/0x6f0 net/core/dev.c:5855
     tun_rx_batched+0x1ba/0x730 drivers/net/tun.c:1556
     tun_get_user+0x283f/0x3bf0 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+0x43b/0x940 fs/read_write.c:584
     ksys_write+0x147/0x250 fs/read_write.c:637
     do_syscall_x64 arch/x86/entry/common.c:51 [inline]
     do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
     entry_SYSCALL_64_after_hwframe+0x68/0xd2