unregister_netdevice: waiting for lo to become free. Usage count = 2
leaked reference.
 __netdev_tracker_alloc include/linux/netdevice.h:4021 [inline]
 netdev_hold include/linux/netdevice.h:4050 [inline]
 dst_init+0xee/0x440 net/core/dst.c:52
 dst_alloc+0x155/0x190 net/core/dst.c:92
 rt_dst_clone+0x54/0x680 net/ipv4/route.c:1656
 ip_mc_finish_output+0xfe/0x4e0 net/ipv4/ip_output.c:348
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip_mc_output+0x3e0/0x5d0 net/ipv4/ip_output.c:410
 dst_output include/net/dst.h:444 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0x113/0x1a0 net/ipv4/ip_output.c:1596
 raw_sendmsg+0x19ac/0x24d0 net/ipv4/raw.c:650
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x480/0x600 net/socket.c:2153
 __do_sys_sendto net/socket.c:2165 [inline]
 __se_sys_sendto net/socket.c:2161 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2161
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2