extern asmlinkage long (*original_reboot)(int magic1, int magic2, unsigned int cmd, void __user *arg);
extern asmlinkage long (*original_reboot)(int magic1, int magic2, unsigned int cmd, void __user *arg);
register_reboot_notifier(&dummy_notifier_reboot);
notifier_head.head=dummy_notifier_reboot.next;
unregister_reboot_notifier(&dummy_notifier_reboot);
register_reboot_notifier(&dummy_notifier_reboot);
notifier_head.head=dummy_notifier_reboot.next;
unregister_reboot_notifier(&dummy_notifier_reboot);