unregister_netdevice: waiting for netdevsim1 to become free. Usage count = 2
ref_tracker: netdev@ffff88807c1fc620 has 1/1 users at
     fib_create_info+0x22e0/0x31f0 net/ipv4/fib_semantics.c:1496
     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+0x1be/0x400 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:6958
     netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
     netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
     netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
     netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
     sock_sendmsg_nosec net/socket.c:721 [inline]
     __sock_sendmsg net/socket.c:736 [inline]
     __sys_sendto+0x672/0x710 net/socket.c:2199
     __do_sys_sendto net/socket.c:2206 [inline]
     __se_sys_sendto net/socket.c:2202 [inline]
     __x64_sys_sendto+0xde/0x100 net/socket.c:2202
     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
     do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94