内核在4.9.82-ti-r102 debian 9.3中写入字符设备文件时抛出错误

Question

我成功地在/dev/文件夹下创建了设备文件，但写入该设备文件会导致内核抛出以下错误消息。

kernel:[10090.943733] Internal error: : 1b [#3] PREEMPT SMP ARM
kernel:[10091.049020] Process echo (pid: 3728, stack limit = 0xdc40a218)
kernel:[10091.054880] Stack: (0xdc40be60 to 0xdc40c000)
kernel:[10091.059267] be60: c15491c6 00000022 dc5cb14c bf30430c dc40bedc dc40be88 c075312c c074fe5c
kernel:[10091.067488] be80: c0753018 ffffff04 ffff0a00 c140414c c0d407c8 bf30430c c140414c 40cfbcf3
kernel:[10091.075709] bea0: 00852878 ffffff04 ffff0a00 00040952 c01a7404 c140414c 00852878 00852878
Segmentation fault

我对Linux设备驱动程序非常了解

有人能帮我吗？？

我附上这个字符设备驱动程序的代码

#include<linux/kernel.h>
#include<linux/init.h>
#include<linux/module.h>
#include<linux/fs.h>
#include<linux/uaccess.h>
#include<linux/device.h>

MODULE_AUTHOR("RUCHA");
MODULE_DESCRIPTION("Character Driver First test");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.0.1");

static int MajorNum;
static struct class* RetValOfClassRegistration = NULL;
static struct device*  RetVal = NULL;
static char message[1024];
static int openDev(struct inode * , struct file *);
static int closeDev(struct inode * , struct file *);
static ssize_t readDev(struct file *, char *, size_t, loff_t *);
static ssize_t writeDev(struct file *, const char *, size_t, loff_t *);
static struct file_operations FileOps = {
.owner = THIS_MODULE,
.open = openDev,
.read = readDev,
.write = writeDev,
.release = closeDev,
};
static int registerCharDev(void){
return register_chrdev(0,"MyDev",&FileOps);
}
static int __init Loaded(void){
// registering device
MajorNum = registerCharDev();
if(MajorNum < 0){
printk("Can not register devicen");
return -1;
}
printk("Driver Loaded with %d n",MajorNum);

// registering device class
RetValOfClassRegistration = class_create(THIS_MODULE,"MyCharacterDriver");
if(RetValOfClassRegistration < 0){
printk("can not register class for driver number : %dn",MajorNum);
return 0;
}

// register the driver
RetVal = device_create(RetValOfClassRegistration,NULL,MKDEV(MajorNum,0),NULL,"MyDev");

return 0;
}

static void __exit Removed(void){
device_destroy(RetValOfClassRegistration,MKDEV(MajorNum,0));
class_unregister(RetValOfClassRegistration);
class_destroy(RetValOfClassRegistration);
unregister_chrdev(MajorNum,"MyDev");
printk("Driver Removedn");
}

module_init(Loaded);
module_exit(Removed);

static int openDev(struct inode *inodep , struct file *filep){
printk("Device is now open to read write operationsn");
return 0;
}

static int closeDev(struct inode *inodep , struct file *filep){
printk("Device Closedn");
return 0;
}
static ssize_t readDev(struct file *filep, char *c, size_t v, loff_t *lp){
printk("Read From the devicen");
return 0;
}
static ssize_t writeDev(struct file *file, const char __user *buf, size_t count, loff_t *offset)
{
sprintf(message, "%s(%zu letters)", buf, len);
return 0;
}

并且用户输入是

echo'1'>/dev/MyDev

Answer 1

您不能直接访问用户数据指针(buf(。您需要先使用copy_from_user将数据复制到内核内存中。此外，请使用snprintf而不是sprintf以避免缓冲区溢出。

此外，在启用调试的情况下进行编译，尤其是CONFIG_DEBUG_INFO，以便在内核日志中获得更有用的错误消息。