static int edal_netdevice_event(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); // struct net_device *dev = NULL; // dev = ptr; switch (event) { case NETDEV_REGISTER: printk(KERN_INFO"###### EDAL NET Interface is Up #######\n"); printk(KERN_INFO"EDAL MESSAGE: %s IS UP\n",dev->name); break; case NETDEV_UNREGISTER: printk(KERN_INFO"###### EDAL NET Interface is Down ######\n"); printk(KERN_INFO"EDAL MESSAGE: %s IS Down\n",dev->name); break; } return 0; } static struct notifier_block edal_netdevice_notifier= { .notifier_call = edal_netdevice_event, .next = NULL, .priority = 1, }; static struct notifier_block edal_netdevice_notifier; static int __init initial(void) { printk(KERN_INFO"This is initialisation function=%s\n",__func__); printk(KERN_INFO"hello kernel\n"); register_netdevice_notifier(&edal_netdevice_notifier); return 0; } void __exit cleanup(void) { printk(KERN_INFO"This is exit function=%s\n",__func__); printk(KERN_INFO"bye kernel\n"); unregister_netdevice_notifier(&edal_netdevice_notifier); } module_init(initial); module_exit(cleanup); When I insmod the module it shows: ###### EDAL NET Interface is Up ####### [ 1315.348657] EDAL MESSAGE: lo IS UP [ 1315.348659] ###### EDAL NET Interface is Up ####### [ 1315.348661] EDAL MESSAGE: eth0 IS UP [ 1315.348663] ###### EDAL NET Interface is Up ####### [ 1315.348665] EDAL MESSAGE: wlan0 IS UP but when I remove the Ethernet Interface It doesn't show anything but when I remove module then it shows: [ 1171.403424] This is exit function=cleanup [ 1171.403428] bye kernel [ 1171.403431] ###### EDAL NET Interface is Down ###### [ 1171.403432] EDAL MESSAGE: lo IS Down [ 1171.403434] ###### EDAL NET Interface is Down ###### [ 1171.403435] EDAL MESSAGE: eth0 IS Down [ 1171.403437] ###### EDAL NET Interface is Down ###### [ 1171.403438] EDAL MESSAGE: wlan0 IS Down Please help!