Question

我正在开发一个内核内存检查器来查找内核空间中的内存泄漏。

我有两个函数profile_vmalloc和profile_vfree，profile_vmalloc使用vmalloc分配内存并将内存分配信息添加到列表中，profile_vfree释放分配的内存并从列表中删除该信息。如何替换vmalloc和vfree以便在编译和运行我的模块时，任何内核模块分配和释放内存都将使用我的函数？
如何使用sysfs创建一个允许用户查看内存泄漏摘要的只读文件？

这是我的代码到目前为止的样子

// Linux Kernel headers
#include    <linux/module.h>
#include    <linux/kernel.h>
#include    <linux/init.h>
#include    <linux/config.h>
#include    <linux/vmalloc.h>

#define  FILE_NAME_LENGTH          256
#define  vmalloc(size)              profile_malloc (block_size, __FILE__, __LINE__)
#define  vfree(mem_ref)                 profile_free(mem_ref)

struct _MEM_INFO
{
    const void          *address;
    size_t              size;
    char                file_name[FILE_NAME_LENGTH];
    size_t              length;
};
typedef struct _MEM_INFO MEM_INFO;

struct _MEM_LEAK {
    MEM_INFO mem_info;
    struct _MEM_LEAK * next;
};
typedef struct _MEM_LEAK MEM_LEAK;



#undef      vmalloc
#undef      vfree


static MEM_PROFILER_LIST * ptr_start = NULL;
static MEM_PROFILER_LIST * ptr_next =  NULL;

/*
 * adds allocated memory info. into the list
 *
 */
void add(MEM_INFO alloc_info)
{

    MEM_PROFILER_LIST * mem_leak_info = NULL;
    mem_leak_info = (MEM_PROFILER_LIST *) malloc (sizeof(MEM_PROFILER_LIST));
    mem_leak_info->mem_info.address = alloc_info.address;
    mem_leak_info->mem_info.size = alloc_info.size;
    strcpy(mem_leak_info->mem_info.file_name, alloc_info.file_name); 
    mem_leak_info->mem_info.line = alloc_info.line;
    mem_leak_info->next = NULL;

    if (ptr_start == NULL)  
    {
        ptr_start = mem_leak_info;
        ptr_next = ptr_start;
    }
    else {
        ptr_next->next = mem_leak_info;
        ptr_next = ptr_next->next;              
    }

}

/*
 * remove memory info. from the list
 *
 */
void erase(unsigned pos)
{

    unsigned int i = 0;
    MEM_PROFILER_LIST * alloc_info, * temp;

    if(pos == 0)
    {
        MEM_PROFILER_LIST * temp = ptr_start;
        ptr_start = ptr_start->next;
        free(temp);
    }
    else 
    {
        for(i = 0, alloc_info = ptr_start; i < pos; 
            alloc_info = alloc_info->next, ++i)
        {
            if(pos == i + 1)
            {
                temp = alloc_info->next;
                alloc_info->next =  temp->next;
                free(temp);
                break;
            }
        }
    }
}

/*
 * deletes all the elements from the list
 */
void clear()
{
    MEM_PROFILER_LIST * temp = ptr_start;
    MEM_PROFILER_LIST * alloc_info = ptr_start;

    while(alloc_info != NULL) 
    {
        alloc_info = alloc_info->next;
        free(temp);
        temp = alloc_info;
    }
}

/*
 * profile of vmalloc
 */
void * profile_vmalloc (unsigned int size, const char * file, unsigned int line)
{
    void * ptr = vmalloc (size);
    if (ptr != NULL) 
    {
        add_mem_info(ptr, size, file, line);
    }
    return ptr;
}


/*
 * profile of free
 */
void profile_free(void * mem_ref)
{
    remove_mem_info(mem_ref);
    free(mem_ref);
}

/*
 * gets the allocated memory info and adds it to a list
 *
 */
void add_mem_info (void * mem_ref, unsigned int size,  const char * file, unsigned int line)
{
    MEM_INFO mem_alloc_info;

    /* fill up the structure with all info */
    memset( &mem_alloc_info, 0, sizeof ( mem_alloc_info ) );
    mem_alloc_info.address  = mem_ref;
    mem_alloc_info.size = size;
    strncpy(mem_alloc_info.file_name, file, FILE_NAME_LENGTH);
    mem_alloc_info.line = line;

    /* add the above info to a list */
    add(mem_alloc_info);
}

/*
 * if the allocated memory info is part of the list, removes it
 *
 */
void remove_mem_info (void * mem_ref)
{
    unsigned int i;
    MEM_PROFILER_LIST  * leak_info = ptr_start;

    /* check if allocate memory is in our list */
    for(i = 0; leak_info != NULL; ++i, leak_info = leak_info->next)
    {
        if ( leak_info->mem_info.address == mem_ref )
        {
            erase ( i );
            break;
        }
    }
}

/*
 * writes a memory leak summary to a file
 */
void mem_leak_summary(void)
{
    unsigned int i;
    MEM_PROFILER_LIST * mem_output;

    FILE * fp_write = fopen (SUMMARY_FILE, "wt");
    char info[1024];

    if(fp_write != NULL)
    {

        fwrite(info, (strlen(info) + 1) , 1, fp_write);
        sprintf(info, "%s\n", "-----------------------------------");   
        fwrite(info, (strlen(info) + 1) , 1, fp_write);

        for(mem_output= ptr_start; mem_output!= NULL; mem_output= mem_output->next)
        {
            sprintf(info, "address : %d\n", leak_info->mem_output.address);
            fwrite(info, (strlen(info) + 1) , 1, fp_write);
            sprintf(info, "size    : %d bytes\n", leak_info->mem_output.size);          
            fwrite(info, (strlen(info) + 1) , 1, fp_write);
            sprintf(info, "line    : %d\n", leak_info->mem_output.line);
            fwrite(info, (strlen(info) + 1) , 1, fp_write);
            sprintf(info, "%s\n", "-----------------------------------");   
            fwrite(info, (strlen(info) + 1) , 1, fp_write);
        }
    }   
    clear();
}

static int __init profiler_init(void)
{
    return 0;
}

static void __exit profiler_cleanup(void)
{
    printk("profiler module uninstalled\n");
}

module_init(profiler_init);
module_exit(profiler_cleanup);
MODULE_LICENSE("GPL");

Answer 1

如何替换vmalloc和vfree 当我编译并运行我的模块任何内核模块分配和释放内存会使用我的功能吗？

第1步。在调用vmalloc＆amp;的文件中vfree，定义宏：

 #define vmalloc(x) profile_vmalloc(x)
 #define vfree(x) profile_vfree(x)

这将确保调用您的函数。

第2步：在profile_*函数的定义中，您是否会计并调用实际的vmalloc/vfree函数。

您已经在执行第2步，因此您只需要处理第1步。

linux内核模块内存检查器

1 个答案: