1. Install
sudo apt-get install valgrind
2. If memory leak
example code:
/* memleak.c */
#include <stdlib.h>
void* memleak(int n)
{
void *p = malloc(n);
return p;
}
memleak.c
/* main.c */
#include <stdio.h>
#include <stdlib.h>
void* memleak(int n);
int main()
{
int i=0;
void *p = NULL;
for(i=0; i<10; i++)
{
p = memleak(100);
printf("allocate memory address: %p\n", p);
}
return 0;
}
main.c
Use ‘valgrind ./exe_binary [cmdline]‘ to check if memory leak happens:
[email protected]:~/test_memleak$ gcc main.c memleak.c -O1 -o main.x [email protected]-VirtualBox:~/test_memleak$ valgrind ./main.x ==6726== Memcheck, a memory error detector ==6726== Copyright (C) 2002-2011, and GNU GPL‘d, by Julian Seward et al. ==6726== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==6726== Command: ./main.x ==6726== allocate memory address: 0x51f2040 allocate memory address: 0x51f20f0 allocate memory address: 0x51f21a0 allocate memory address: 0x51f2250 allocate memory address: 0x51f2300 allocate memory address: 0x51f23b0 allocate memory address: 0x51f2460 allocate memory address: 0x51f2510 allocate memory address: 0x51f25c0 allocate memory address: 0x51f2670 ==6726== ==6726== HEAP SUMMARY: ==6726== in use at exit: 1,000 bytes in 10 blocks ==6726== total heap usage: 10 allocs, 0 frees, 1,000 bytes allocated ==6726== ==6726== LEAK SUMMARY: ==6726== definitely lost: 1,000 bytes in 10 blocks ==6726== indirectly lost: 0 bytes in 0 blocks ==6726== possibly lost: 0 bytes in 0 blocks ==6726== still reachable: 0 bytes in 0 blocks ==6726== suppressed: 0 bytes in 0 blocks ==6726== Rerun with --leak-check=full to see details of leaked memory ==6726== ==6726== For counts of detected and suppressed errors, rerun with: -v ==6726== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
3. Where memory leak
$ gcc main.c memleak.c -O1 -g -o main.x
$ valgrind --leak-check=full ./main.x
ATTENTION:
- "-O1" to prevent from inline functions by optimization, "-g" to get line number of memory leak functions.
- In one word, use "DEBUG" flavour instead of "release" while finding memleak.
[email protected]:~/test_memleak$ valgrind --leak-check=full ./main.x [email protected]-VirtualBox:~/test_memleak$ valgrind --leak-check=full ./x ==7209== Memcheck, a memory error detector ==7209== Copyright (C) 2002-2011, and GNU GPL‘d, by Julian Seward et al. ==7209== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==7209== Command: ./x ==7209== allocate memory address: 0x51f2040 allocate memory address: 0x51f20f0 allocate memory address: 0x51f21a0 allocate memory address: 0x51f2250 allocate memory address: 0x51f2300 allocate memory address: 0x51f23b0 allocate memory address: 0x51f2460 allocate memory address: 0x51f2510 allocate memory address: 0x51f25c0 allocate memory address: 0x51f2670 ==7209== ==7209== HEAP SUMMARY: ==7209== in use at exit: 1,000 bytes in 10 blocks ==7209== total heap usage: 10 allocs, 0 frees, 1,000 bytes allocated ==7209== ==7209== 1,000 bytes in 10 blocks are definitely lost in loss record 1 of 1 ==7209== at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==7209== by 0x4005A3: memleak (memleak.c:5) ==7209== by 0x400573: main (main.c:12) ==7209== ==7209== LEAK SUMMARY: ==7209== definitely lost: 1,000 bytes in 10 blocks ==7209== indirectly lost: 0 bytes in 0 blocks ==7209== possibly lost: 0 bytes in 0 blocks ==7209== still reachable: 0 bytes in 0 blocks ==7209== suppressed: 0 bytes in 0 blocks ==7209== ==7209== For counts of detected and suppressed errors, rerun with: -v ==7209== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2) [email protected]-VirtualBox:~/test_memleak$
You can see the call stack, which means where memory leak happens
main() ==> memleak() ==> malloc()
4. Find memory leak because of invoking 3rd-party library
Use the same method as above.
【Valgrind】How to check memory leak and where it's in 10 mins,布布扣,bubuko.com
【Valgrind】How to check memory leak and where it's in 10 mins
时间： 2024-12-26 09:16:09