Valgrind 使用简单说明

原谅我的转载，但的Valgrind 确是一个RD所需要掌握的，也是对自己产品的负责。

 

Valgrind是一个GPL的软件，用于Linux（For x86, amd64 and ppc32）程序的内存调试和代码剖析。你可以在它的环境中运行你的程序来监视内存的使用情况，比如C 语言中的malloc和free或者 C++中的new和 delete。使用Valgrind的工具包，你可以自动的检测许多内存管理和线程的bug，避免花费太多的时间在bug寻找上，使得你的程序更加稳固。

Valgrind工具包包含多个工具，如Memcheck,Cachegrind,Helgrind, Callgrind，Massif。下面分别介绍个工具的作用：

Memcheck 工具主要检查下面的程序错误：

• 使用未初始化的内存 (Use of uninitialised memory)
• 使用已经释放了的内存 (Reading/writing memory after it has been free’d)
• 使用超过 malloc分配的内存空间(Reading/writing off the end of malloc’d blocks)
• 对堆栈的非法访问 (Reading/writing inappropriate areas on the stack)
• 申请的空间是否有释放 (Memory leaks – where pointers to malloc’d blocks are lost forever)
• malloc/free/new/delete申请和释放内存的匹配(Mismatched use of malloc/new/new [] vs free/delete/delete [])
• src和dst的重叠(Overlapping src and dst pointers in memcpy() and related functions)

Callgrind收集程序运行时的一些数据，函数调用关系等信息，还可以有选择地进行cache 模拟。在运行结束时，它会把分析数据写入一个文件。callgrind_annotate可以把这个文件的内容转化成可读的形式。

它模拟 CPU中的一级缓存I1,D1和L2二级缓存，能够精确地指出程序中 cache的丢失和命中。如果需要，它还能够为我们提供cache丢失次数，内存引用次数，以及每行代码，每个函数，每个模块，整个程序产生的指令数。这对优化程序有很大的帮助。

它主要用来检查多线程程序中出现的竞争问题。Helgrind 寻找内存中被多个线程访问，而又没有一贯加锁的区域，这些区域往往是线程之间失去同步的地方，而且会导致难以发掘的错误。Helgrind实现了名为” Eraser” 的竞争检测算法，并做了进一步改进，减少了报告错误的次数。

堆栈分析器，它能测量程序在堆栈中使用了多少内存，告诉我们堆块，堆管理块和栈的大小。Massif能帮助我们减少内存的使用，在带有虚拟内存的现代系统中，它还能够加速我们程序的运行，减少程序停留在交换区中的几率。

1、 到www.valgrind.org下载最新版valgrind-3.2.3.tar.bz2
2、 解压安装包：tar –jxvf valgrind-3.2.3.tar.bz2
3、 解压后生成目录valgrind-3.2.3 
4、 cd valgrind-3.2.3
5、 ./configure
6、 Make;make install

用法: valgrind [options] prog-and-args [options]: 常用选项，适用于所有Valgrind工具

1. -tool= 最常用的选项。运行 valgrind中名为toolname的工具。默认memcheck。
2. h –help 显示帮助信息。
3. -version 显示valgrind内核的版本，每个工具都有各自的版本。
4. q –quiet 安静地运行，只打印错误信息。
5. v –verbose 更详细的信息, 增加错误数统计。
6. -trace-children=no|yes 跟踪子线程? [no]
7. -track-fds=no|yes 跟踪打开的文件描述？[no]
8. -time-stamp=no|yes 增加时间戳到LOG信息? [no]
9. -log-fd= 输出LOG到描述符文件 [2=stderr]
10. -log-file= 将输出的信息写入到filename.PID的文件里，PID是运行程序的进行ID
11. -log-file-exactly= 输出LOG信息到 file
12. -log-file-qualifier= 取得环境变量的值来做为输出信息的文件名。 [none]
13. -log-socket=ipaddr:port 输出LOG到socket ，ipaddr:port

LOG信息输出

1. -xml=yes 将信息以xml格式输出，只有memcheck可用
2. -num-callers= show callers in stack traces [12]
3. -error-limit=no|yes 如果太多错误，则停止显示新错误? [yes]
4. -error-exitcode= 如果发现错误则返回错误代码 [0=disable]
5. -db-attach=no|yes 当出现错误，valgrind会自动启动调试器gdb。[no]
6. -db-command= 启动调试器的命令行选项[gdb -nw %f %p]

适用于Memcheck工具的相关选项：

1. -leak-check=no|summary|full 要求对leak给出详细信息? [summary]
2. -leak-resolution=low|med|high how much bt merging in leak check [low]
3. -show-reachable=no|yes show reachable blocks in leak check? [no]

下面是一段有问题的C程序代码test.c

＃i nclude 
void f(void)
{
   int* x = malloc(10 * sizeof(int));
   x[10] = 0;  //问题1: 数组下标越界
}                  //问题2: 内存没有释放

int main(void)
{
   f();
   return 0;
 }

1、 编译程序test.c
gcc -Wall test.c -g -o test
2、 使用Valgrind检查程序BUG
valgrind --tool=memcheck --leak-check=full ./test
3、 分析输出的调试信息
==3908== Memcheck, a memory error detector.
==3908== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==3908== Using LibVEX rev 1732, a library for dynamic binary translation.
==3908== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==3908== Using valgrind-3.2.3, a dynamic binary instrumentation framework.
==3908== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==3908== For more details, rerun with: -v
==3908== 
--3908-- DWARF2 CFI reader: unhandled CFI instruction 0:50
--3908-- DWARF2 CFI reader: unhandled CFI instruction 0:50
/*数组越界错误*/
==3908== Invalid write of size 4      
==3908==    at 0x8048384: f (test.c:6)
==3908==    by 0x80483AC: main (test.c:11)
==3908==  Address 0x400C050 is 0 bytes after a block of size 40 alloc'd
==3908==    at 0x40046F2: malloc (vg_replace_malloc.c:149)
==3908==    by 0x8048377: f (test.c:5)
==3908==    by 0x80483AC: main (test.c:11)
==3908== 
==3908== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 14 from 1)
==3908== malloc/free: in use at exit: 40 bytes in 1 blocks. 
==3908== malloc/free: 1 allocs, 0 frees, 40 bytes allocated.
==3908== For counts of detected errors, rerun with: -v
==3908== searching for pointers to 1 not-freed blocks.
==3908== checked 59,124 bytes.
==3908== 
==3908== 
/*有内存空间没有释放*/
==3908== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1
==3908==    at 0x40046F2: malloc (vg_replace_malloc.c:149)
==3908==    by 0x8048377: f (test.c:5)
==3908==    by 0x80483AC: main (test.c:11)
==3908== 
==3908== LEAK SUMMARY:
==3908==    definitely lost: 40 bytes in 1 blocks.
==3908==      possibly lost: 0 bytes in 0 blocks.
==3908==    still reachable: 0 bytes in 0 blocks.
==3908==         suppressed: 0 bytes in 0 blocks.

附内存占用表：

--------------------------------------------------------------------------------
  n        time(i)         total(B)   useful-heap(B) extra-heap(B)
stacks(B)
--------------------------------------------------------------------------------
 69  1,960,678,424       15,953,352       15,077,080       876,272
0
 70  1,978,734,481       15,943,736       15,067,480       876,256
0
 71  1,997,140,926       15,943,736       15,067,480       876,256
0
 72  2,015,695,615       15,943,736       15,067,480       876,256
0
 73  2,034,038,837       15,943,736       15,067,480       876,256
0
 74  2,052,495,904       15,943,736       15,067,480       876,256
0
 75  2,070,419,744       15,943,736       15,067,480       876,256
0
 76  2,088,911,237       15,943,736       15,067,480       876,256
0
 77  2,109,363,396       15,960,872       15,084,580       876,292
0
 78  2,127,250,762       15,894,184       15,017,944       876,240
0
94.49% (15,017,944B) (heap allocation functions) malloc/new/new[], --alloc-fns, etc.
->74.76% (11,882,444B) 0x465FEBB: gdk_pixbuf_new
(in /usr/lib/libgdk_pixbuf-2.0.so.0.1200.9)
| ->74.75% (11,880,844B) 0x5FF8C63:
(within /usr/lib/gtk-2.0/2.10.0/loaders/libpixbufloader-png.so)
| | ->74.75% (11,880,844B) 0x466364F:
(within /usr/lib/libgdk_pixbuf-2.0.so.0.1200.9)
| |   ->74.75% (11,880,844B) 0x46644CC: gdk_pixbuf_new_from_file
(in /usr/lib/libgdk_pixbuf-2.0.so.0.1200.9)
| |     ->20.91% (3,323,792B) 0x805F0E2: style_keybg_draw (style.c:812)
| |     | 
| |     ->20.20% (3,210,112B) 0x80567CE: keyboard_set_background
(keyboard.c:1398)
| |     | 
| |     ->18.82% (2,991,240B) 0x805FE7B: style_symbol_draw (style.c:370)
| |     | 
| |     ->11.91% (1,893,612B) 0x805E950: style_symbolkb_symbol_draw
(style.c:686)
| |     | 
| |     ->02.12% (336,960B) 0x805F538: style_keybg_switch (style.c:608)
| |     | 
| |     ->00.79% (125,128B) in 1+ places, all below ms_print's threshold
(01.00%)
| |     
| ->00.01% (1,600B) in 1+ places, all below ms_print's threshold
(01.00%)
| 
->06.40% (1,017,493B) in 746 places, all below massif's threshold
(01.00%)
| 
->04.59% (729,808B) 0x402115F: posix_memalign (vg_replace_malloc.c:569)
| ->04.59% (729,808B) 0x48A2373:
(within /usr/lib/libglib-2.0.so.0.1600.6)
|   ->03.99% (634,088B) 0x48A35A0: g_slice_alloc
(in /usr/lib/libglib-2.0.so.0.1600.6)
|   | ->02.43% (385,888B) 0x487954C:
(within /usr/lib/libglib-2.0.so.0.1600.6)
|   | | ->01.93% (307,024B) 0x43583F2:
(within /usr/lib/libgtk-x11-2.0.so.0.1200.9)
|   | | | 
|   | | ->00.50% (78,864B) in 1+ places, all below ms_print's threshold
(01.00%)
|   | | 
|   | ->01.56% (248,200B) in 18 places, all below massif's threshold
(01.00%)
|   |   
|   ->00.60% (95,720B) in 1+ places, all below ms_print's threshold
(01.00%)
|   
->04.01% (637,469B) 0x4E79B1C: (within /usr/lib/libfreetype.so.6.3.16)
| ->04.01% (637,469B) 0x4E7D34A: ft_mem_qalloc
(in /usr/lib/libfreetype.so.6.3.16)
|   ->04.01% (637,469B) 0x4E7EFF2: ft_mem_alloc
(in /usr/lib/libfreetype.so.6.3.16)
|     ->03.75% (595,667B) 0x4E7F124: ft_mem_qrealloc
(in /usr/lib/libfreetype.so.6.3.16)
|     | ->03.75% (595,667B) 0x4E7F20E: ft_mem_realloc
(in /usr/lib/libfreetype.so.6.3.16)
|     |   
|     ->00.26% (41,802B) in 1+ places, all below ms_print's threshold
(01.00%)
|     
->02.11% (334,906B) 0x48A6FD0: g_strndup
(in /usr/lib/libglib-2.0.so.0.1600.6)
| ->02.11% (334,759B) 0x435771A:
(within /usr/lib/libgtk-x11-2.0.so.0.1200.9)
| | ->02.07% (329,754B) 0x435839D:
(within /usr/lib/libgtk-x11-2.0.so.0.1200.9)
| | | ->01.06% (168,149B) in 2 places, all below massif's threshold
(01.00%)
| | | | 
| | | ->01.02% (161,605B) 0x435825D:
(within /usr/lib/libgtk-x11-2.0.so.0.1200.9)
| | |   ->01.02% (161,605B) in 2 places, all below massif's threshold
(01.00%)
| | |     
| | ->00.03% (5,005B) in 1+ places, all below ms_print's threshold
(01.00%)
| | 
| ->00.00% (147B) in 1+ places, all below ms_print's threshold (01.00%)
| 
->01.48% (235,020B) 0x42337FC: art_alloc
(in /usr/lib/libart_lgpl_2.so.2.3.20)
| ->01.48% (235,020B) in 30 places, all below massif's threshold
(01.00%)
|   
->01.14% (180,804B) 0x8056952: keyboard_setsize (keyboard.c:1441)
  ->01.14% (180,804B) 0x805E526: layoutreader_readkeyboard
(layoutreader.c:314)
    ->01.14% (180,804B) 0x80583B0: keyboard_new (keyboard.c:1479)
      ->01.14% (180,804B) 0x8054D99: flo_add_extension (florence.c:364)
        ->01.14% (180,804B) 0x8055561: flo_set_curr_layout
(florence.c:673)
        | 
        ->00.00% (0B) in 1+ places, all below ms_print's threshold
(01.00%)
        
--------------------------------------------------------------------------------
  n        time(i)         total(B)   useful-heap(B) extra-heap(B)
stacks(B)
--------------------------------------------------------------------------------
 79  2,145,129,854       15,907,992       15,027,431       880,561
0
(END)