尝试加载内核模块时，如何解决C ++中的malloc（）错误？

Question

I am getting the error malloc(): memory corruption when I execute this code in C++. Basically, I open a kernel file and I use malloc with the size of struct stat st . I guess this is causing the problem.

The code loads a kernel module (I2C) and it is actually loading. but I guess I am not using the malloc() as should be used. Thanks.

#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>

#include <gtest/gtest.h>
#include <gmock/gmock.h>

#define init_module(mod, len, opts) syscall(__NR_init_module, mod, len, opts)
#define delete_module(name, flags) syscall(__NR_delete_module, name, flags)
class I2CKernelModule : public testing::Test {
public:
    I2CKernelModule() {
    }
};
TEST_F(I2CKernelModule, TestAddAndRemoveKernelModule) {
    char *params;
    int fd;
    size_t image_size;
    struct stat st;
    void *image;

    // command: sudo insmod /root/i2c-tests/i2c-stub.ko chip_addr=0x20
    params = "chip_addr=0x20";
    fd = open("/root/i2c-tests/i2c-stub.ko", O_RDONLY);
    fstat(fd, &st);
    image_size = st.st_size;
    image = malloc(image_size);
    read(fd, image, image_size);
    close(fd);
    if (init_module(image, image_size, params) != 0) {
        perror("init_module");
        GTEST_FAIL();
    }
    free(image);
    GTEST_SUCCESS_("Kernel module loaded.");

    /*
    // sudo rmmod i2c_stub
    if (delete_module("i2c_stub", O_NONBLOCK) != 0) {
        perror("delete_module");
        GTEST_FAIL();
    }
    GTEST_SUCCESS_("Kernel module unloaded.");
    */
}

Answer 1

Check the return values of all functions for errors. The code you have listed would fail if the file doesn't open, the stat fails or the malloc fails. It is also a good idea to check the number of bytes returned by read.