linux内核模块内存检查器

Question

我正在开发内核内存检查器来查找内核空间中的内存泄漏。

1. 我有两个功能profile_vmalloc和profile_vfree，profile_vmalloc使用vmalloc的分配内存并增加了内存分配信息到一个列表，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？

2. 如何使用sysfs创建一个只读文件，该文件将允许用户查看内存泄漏摘要？

这是我的代码是什么样子至今

// 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

如何更换vmalloc的和vfree所以 ，当我编译和运行我的模块的任何内核模块分配和 释放内存会使用我的功能？

步骤1.在调用vmalloc & vfree文件，定义宏：

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

这将确保你的函数被调用。

第2步：在您定义的profile_*函数中，您是否记账并调用实际的vmalloc/vfree函数。

你已经在做第2步，所以你只需要采取的步骤的护理1.