malloc/new 调用在堆上分配的内存却没有相应的free/delete;
会逐渐吃掉虚拟内存
如何判断是否内存泄漏
如何判断在代码中哪里泄漏
#define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <dlfcn.h> #define MEM_CONTENT_LEN 128 typedef void *(*malloc_t)(size_t size); malloc_t malloc_f = NULL; typedef void(*free_t)(void *P); free_t free_f; int enable_malloc_hook = 1; int enable_free_hook = 1; void *malloc(size_t size){ if (enable_malloc_hook) { enable_malloc_hook = 0; //防止递归;不这么设计会发生循环调用 ,printf也会调用malloc 直接打印观察是否泄漏 void *p = malloc_f(size); // printf("malloc\n"); /* 参数: 0:当前函数在哪调用: 返回==f()-->malloc 1: a()-->f()-->malloc 2: a()-->b()-->f()-->malloc */ void *caller = __builtin_return_address(0); char buff[MEM_CONTENT_LEN] = {0}; //具体是否泄漏,何处泄漏,打印到文件中 sprintf(buff,"./mem/%p.mem",p); FILE *fp = fopen(buff,"w"); fprintf(fp,"[+%p]malloc --> addr: %p,size: %lu\n",caller,p,size); fflush(fp); enable_malloc_hook = 1; return p; } else{ return malloc_f(size); } } void free(void *p){ // printf("free\n"); if (enable_free_hook) { enable_free_hook = 0; char buff[MEM_CONTENT_LEN] = {0}; //具体是否泄漏,何处泄漏 sprintf(buff,"./mem/%p.mem",p); if (unlink(buff) <0) { printf("double free:%p\n",p); } enable_free_hook= 1; }else{ free_f(p); } } static int init_hook(){ malloc_f = dlsym(RTLD_NEXT,"malloc"); free_f = dlsym(RTLD_NEXT,"free"); } int main(){ init_hook(); // hook调用 void *p = malloc(10); free(p); void *p1 = malloc(20); void *p2 = malloc(30); free(p1); }
gcc -o hook hook.c -ldl #编译
mkdir mem #存储文件
./hook #进行检查,若mem中生成了文件,则说明出了内存泄漏的问题
cat mem/0x55a3d3e666c0.mem # 具体泄露:[+0x55a3d381a59e]malloc --> addr: 0x55a3d3e666c0,size: 30addr2line -fe ./hook -a 0x55a3d381a59e#检查具体泄露的出现代码地址
#define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <dlfcn.h> #define MEM_CONTENT_LEN 128 void *malloc_hook(size_t size,const char* file, int line){ void *p = malloc(size); char buff[MEM_CONTENT_LEN] = {0}; //具体是否泄漏,何处泄漏,打印到文件中 sprintf(buff,"./mem/%p.mem",p); FILE *fp = fopen(buff,"w"); fprintf(fp,"[+%s:%d]malloc --> addr: %p,size: %lu\n",file,line,p,size); fflush(fp); return p; } void* free_hook(void *p,const char* file,int line) { char buff[MEM_CONTENT_LEN] = {0}; //具体是否泄漏,何处泄漏 sprintf(buff,"./mem/%p.mem",p); if (unlink(buff) <0) { printf("double free:%p\n",p); } free(p); } //如果宏定义放在函数实现前面,会出现循环调用 #define malloc(size) malloc_hook(size,__FILE__,__LINE__) #define free(p) free_hook(p,__FILE__,__LINE__) int main(){ void *p = malloc(10); free(p); void *p1 = malloc(20); void *p2 = malloc(30); free(p1); }
其中[+hook_def.c:39]说明了文件中的多少行出了问题;