当内核出现Segmentation fault.(例如访问一个并不存在的虚拟地址),Oops会被打印到控制台上。假设对应的设备节点是/dev/oops_example 通过 echo 1> /dev/oops_example 写设备文件 则会在控制台上打印 NULL pointer 错误 并给出错误地址在oopsexam_write
通过 cat /dev/oops_example 命令读设备文件。
#define MAJOR_NUM 251 //主设备号
static ssize_t oopsexam_read(struct file *, char *, size_t, loff_t*);
static ssize_t oopsexam_write(struct file *, const char *, size_t, loff_t*);
//初始化字符设备驱动的file_operations结构体
struct file_operations oopsexam_fops =
{
read: oopsexam_read, write: oopsexam_write,
};
static int __init oopsexam_init(void)
{
int ret;
//注册设备驱动
ret = register_chrdev(MAJOR_NUM, "oopsexam", &oopsexam_fops);
if (ret)
{
printk("oopsexam register failure");
}
else
{
printk("oopsexam register success");
}
return ret;
}
static void __exit oopsexam_exit(void)
{
int ret;
//注销设备驱动
ret = unregister_chrdev(MAJOR_NUM, "oopsexam");
if (ret)
{
printk("oopsexam unregister failure");
}
else
{
printk("oopsexam unregister success");
}
}
static ssize_t oopsexam_read(struct file *filp, char *buf, size_t len, loff_t *off)
{
int *p=0;
*p = 1; //create oops
return len;
}
static ssize_t oopsexam_write(struct file *filp, const char *buf, size_t len, loff_t
*off)
{
int *p=0;
*p = 1; //create oops
return len;
}
module_init(oopsexam_init);
module_exit(oopsexam_exit);
MODULE_AUTHOR("Song Baohua");
MODULE_LICENSE("Dual BSD/GPL");