unregister_netdevice: waiting for eth4 to become free. Usage count = 2
ref_tracker: netdev@ffff8880642506d8 has 1/1 users at
     fib_create_info+0x22e0/0x31f0 net/ipv4/fib_semantics.c:1495
     fib_table_insert+0xc8/0x1b50 net/ipv4/fib_trie.c:1212
     fib_magic+0x434/0x510 net/ipv4/fib_frontend.c:1134
     fib_add_ifaddr+0x144/0x5f0 net/ipv4/fib_frontend.c:1156
     fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1470
     notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
     blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
     __inet_insert_ifa+0x9e9/0xbc0 net/ipv4/devinet.c:566
     inet_rtm_newaddr+0x10d8/0x1ad0 net/ipv4/devinet.c:1001
     rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6996
     netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
     netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
     netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1344
     netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
     sock_sendmsg_nosec net/socket.c:787 [inline]
     __sock_sendmsg net/socket.c:802 [inline]
     ____sys_sendmsg+0x94c/0x9c0 net/socket.c:2698
     ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
     __sys_sendmsg net/socket.c:2784 [inline]
     __do_sys_sendmsg net/socket.c:2789 [inline]
     __se_sys_sendmsg net/socket.c:2787 [inline]
     __x64_sys_sendmsg+0x1c3/0x2a0 net/socket.c:2787