内存泄露调试笔记一例

发布于 2015-01-14 17:44:35 浏览：643 订阅该版

刚好碰到一内存泄露问题，但不知道是谁泄露了，翻出之前调试用过的代码改了一下，很快找到泄露者了。

先是对mem.c进行改造，给每个node加入更多信息，以方便追溯。
```diff
src/mem.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 53 insertions(+), 2 deletions(-)

diff --git a/src/mem.c b/src/mem.c
index 004de01..5f83700 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -112,6 +112,11 @@ struct heap_mem
     rt_uint16_t used;
 
     rt_size_t next, prev;
+
+    rt_tick_t tick;
+    char thread_name[12];
+    char file_name[128];
+    int line;
 };
 
 /** pointer to the heap: for alignment, heap_ptr is now a pointer instead of an array */
@@ -230,6 +235,45 @@ void rt_system_heap_init(void *begin_addr, void *end_addr)
     lfree = (struct heap_mem *)heap_ptr;
 }
 
+static void mem_dump(void)
+{
+    const struct heap_mem * mem;
+    int count = 0;
+    rt_tick_t tick;
+
+    rt_enter_critical();
+
+    tick = rt_tick_get();
+
+    mem = (struct heap_mem *)heap_ptr;
+
+    rt_kprintf("mem_dump heap_ptr:0x%08X heap_end:0x%08X
", (int)heap_ptr, (int)heap_end);
+    while(mem < heap_end)
+    {
+        rt_kprintf("mem #%d: 0x%08X
", count, (int)mem);
+        rt_kprintf("magic: %04X %s
", mem->magic, (mem->used)?"used":"free");
+        //rt_kprintf("size %d
", (int)());
+
+        if(mem->used)
+        {
+            rt_kprintf("thread: %s, age %d
", mem->thread_name, tick - mem->tick);
+            rt_kprintf("%s L:%d
", mem->file_name, mem->line);
+        }
+
+        mem = (struct heap_mem *)&heap_ptr[mem->next];
+
+        count++;
+        rt_kprintf("
");
+    }
+    rt_kprintf("mem_dump end
");
+
+    rt_exit_critical();
+}
+#ifdef RT_USING_FINSH
+#include <finsh.h>
+FINSH_FUNCTION_EXPORT_ALIAS(mem_dump, mem_dump, webclient multiple download test);
+#endif /* RT_USING_FINSH */
+
 /**
  * @addtogroup MM
  */
@@ -243,7 +287,7 @@ void rt_system_heap_init(void *begin_addr, void *end_addr)
  *
  * @return pointer to allocated memory or NULL if no free memory was found.
  */
-void *rt_malloc(rt_size_t size)
+void *rt_malloc_debug(rt_size_t size, const char * file, int line)
 {
     rt_size_t ptr, ptr2;
     struct heap_mem *mem, *mem2;
@@ -363,6 +407,13 @@ void *rt_malloc(rt_size_t size)
             RT_OBJECT_HOOK_CALL(rt_malloc_hook,
                                 (((void *)((rt_uint8_t *)mem + SIZEOF_STRUCT_MEM)), size));
 
+            //debug
+            mem->tick = rt_tick_get();
+            strncpy(mem->thread_name, rt_thread_self()->name, RT_NAME_MAX);
+            strncpy(mem->file_name, file, sizeof(mem->file_name) - 1);
+            mem->file_name = '�';
+            mem->line = line;
+
             /* return the memory data except mem struct */
             return (rt_uint8_t *)mem + SIZEOF_STRUCT_MEM;
         }
@@ -372,7 +423,7 @@ void *rt_malloc(rt_size_t size)
 
     return RT_NULL;
 }
-RTM_EXPORT(rt_malloc);
+//RTM_EXPORT(rt_malloc);
 
 /**
  * This function will change the previously allocated memory block.
```

然后把rtthread.h中的rt_malloc指向新rt_malloc_debug
```diff
include/rtthread.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/rtthread.h b/include/rtthread.h
index edd207b..94830a7 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -222,7 +222,8 @@ void rt_mp_free_sethook(void (*hook)(struct rt_mempool *mp, void *block));
  */
 void rt_system_heap_init(void *begin_addr, void *end_addr);
 
-void *rt_malloc(rt_size_t nbytes);
+void *rt_malloc_debug(rt_size_t size, const char * file, int line);
+#define rt_malloc(size)	rt_malloc_debug(size, __FILE__, __LINE__)
 void rt_free(void *ptr);
 void *rt_realloc(void *ptr, rt_size_t nbytes);
 void *rt_calloc(rt_size_t count, rt_size_t size);
```

然后执行测试程序，让内存多泄露一些，并让时间久一点，然后mem_dump()就能很明显找出泄露者了。