c++ - 如何使用 Valgrind 确定 "still-available"内存泄漏的来源？

Question

我有一个我写的程序，它的内存占用随着时间的推移而增长。它最终会耗尽所有可用的系统内存，然后导致系统崩溃。

我正在尝试确定似乎是内存泄漏的来源。我已经在代码上运行了 Valgrind。它报告没有明确或间接失去内存。它确实列出了可能丢失的内存，但不够清晰。我可以使用一些关于如何追踪此问题的建议。

==13049== HEAP SUMMARY:
==13049==     in use at exit: 2,240,095 bytes in 3,720 blocks
==13049==   total heap usage: 50,296 allocs, 46,576 frees, 768,607,751 bytes allocated
==13049==
==13049== Searching for pointers to 3,720 not-freed blocks
==13049== Checked 56,807,736 bytes
==13049==
==13049== Thread 1:
==13049== 64 bytes in 4 blocks are possibly lost in loss record 1 of 11
==13049==    at 0x4844F70: malloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: possible
   fun:malloc
}
==13049== 184 bytes in 1 blocks are possibly lost in loss record 2 of 11
==13049==    at 0x48472C4: realloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: possible
   fun:realloc
}
==13049== 520 bytes in 20 blocks are possibly lost in loss record 3 of 11
==13049==    at 0x48473FC: memalign (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: possible
   fun:memalign
}
==13049== 643 bytes in 11 blocks are still reachable in loss record 4 of 11
==13049==    at 0x4845DFC: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:_Znam
}
==13049== 944 bytes in 47 blocks are still reachable in loss record 5 of 11
==13049==    at 0x4844F70: malloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc
}
==13049== 3,408 bytes in 19 blocks are possibly lost in loss record 6 of 11
==13049==    at 0x48470CC: calloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: possible
   fun:calloc
}
==13049== 5,056 bytes in 7 blocks are still reachable in loss record 7 of 11
==13049==    at 0x48472C4: realloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:realloc
}
==13049== 37,304 bytes in 185 blocks are still reachable in loss record 8 of 11
==13049==    at 0x48470CC: calloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:calloc
}
==13049== 97,782 bytes in 1,739 blocks are still reachable in loss record 9 of 11
==13049==    at 0x48456C8: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:_Znwm
}
==13049== 124,585 bytes in 1,666 blocks are still reachable in loss record 10 of 11
==13049==    at 0x4845040: malloc (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc
}
==13049== 1,969,605 bytes in 21 blocks are still reachable in loss record 11 of 11
==13049==    at 0x48473FC: memalign (in /usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)
==13049==
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:memalign
}
==13049== LEAK SUMMARY:
==13049==    definitely lost: 0 bytes in 0 blocks
==13049==    indirectly lost: 0 bytes in 0 blocks
==13049==      possibly lost: 4,176 bytes in 44 blocks
==13049==    still reachable: 2,235,919 bytes in 3,676 blocks
==13049==                       of which reachable via heuristic:
==13049==                         newarray           : 1,536 bytes in 16 blocks
==13049==         suppressed: 0 bytes in 0 blocks

调用 Valgrind 时:


valgrind --child-silent-after-fork=yes --smc-check=stack --tool=memcheck --gen-suppressions=all --track-origins=yes --leak-check=full --num-callers =500 --leak-check=full --show-leak-kinds=all -v --show-reachable=yes/opt/fsoapp/bin/fsoapp


Answer 1

使用选项

   --leak-check=full --show-leak-kinds=all

在程序终止时获取仍可访问的内存列表。

您还可以使用 gdb+vgdb 和 valgrind 以交互方式搜索泄漏。参见 http://www.valgrind.org/docs/manual/mc-manual.html#mc-manual.monitor-commands

特别是，监控命令“block_list”和“who_points_at”可以帮助找到内存保存的位置。