unregister_netdevice: waiting for batadv_slave_0 to become free. Usage count = 2
ref_tracker: netdev@ffff888038d30610 has 1/1 users at
     batadv_hard_if_event+0xf0f/0x1730
     notifier_call_chain+0x1b6/0x3e0
     register_netdevice+0x1608/0x1ae0
     veth_newlink+0x5cc/0xa50
     rtnl_newlink_create+0x310/0xb00
     rtnl_newlink+0x16d6/0x1c70
     rtnetlink_rcv_msg+0x7cf/0xb70
     netlink_rcv_skb+0x208/0x470
     netlink_unicast+0x82f/0x9e0
     netlink_sendmsg+0x805/0xb30
     __sock_sendmsg+0x21c/0x270
     __sys_sendto+0x3bd/0x520
     __x64_sys_sendto+0xde/0x100
     do_syscall_64+0xfa/0x3b0
     entry_SYSCALL_64_after_hwframe+0x77/0x7f

