#include <linux/kernel.h>#include <linux/cpu.h>#include <linux/module.h>#include <linux/notifier.h> static int priority;static int cpu_up_prepare_error;static int cpu_down_prepare_error; module_param(priority, int, 0);MODULE_PARM_DESC(priority, "specify cpu notifier priority"); module_param(cpu_up_prepare_error, int, 0644);MODULE_PARM_DESC(cpu_up_prepare_error,		"specify error code to inject CPU_UP_PREPARE action"); module_param(cpu_down_prepare_error, int, 0644);MODULE_PARM_DESC(cpu_down_prepare_error,		"specify error code to inject CPU_DOWN_PREPARE action"); static int err_inject_cpu_callback(struct notifier_block *nfb,				unsigned long action, void *hcpu){	int err = 0; 	switch (action) {	case CPU_UP_PREPARE:	case CPU_UP_PREPARE_FROZEN:		err = cpu_up_prepare_error;		break;	case CPU_DOWN_PREPARE:	case CPU_DOWN_PREPARE_FROZEN:		err = cpu_down_prepare_error;		break;	}	if (err)		printk(KERN_INFO "Injecting error (%d) at cpu notifier\n", err); 	return notifier_from_errno(err);} static struct notifier_block err_inject_cpu_notifier = {	.notifier_call = err_inject_cpu_callback,}; static int err_inject_init(void){	err_inject_cpu_notifier.priority = priority; 	return register_hotcpu_notifier(&err_inject_cpu_notifier);} static void err_inject_exit(void){	unregister_hotcpu_notifier(&err_inject_cpu_notifier);} module_init(err_inject_init);module_exit(err_inject_exit); MODULE_DESCRIPTION("CPU notifier error injection module");MODULE_LICENSE("GPL");MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");