c++ - Valgrind 显示内存泄漏且 main 为空，不包含 header

Question

卢本图 15.10

我的项目存在内存泄漏。我可以找到它们，所以我清理了我的 main.cpp 文件，现在它看起来像这样:

int main()
{
   return 0;
}

当我使用命令检查内存时:

valgrind --leak-check=full --show-leak-kinds=all ./MyProgram > log1.txt 2>&1

我遇到了这些错误:

==5219== 
==5219== LEAK SUMMARY:
==5219==    definitely lost: 0 bytes in 0 blocks
==5219==    indirectly lost: 0 bytes in 0 blocks
==5219==      possibly lost: 728 bytes in 18 blocks
==5219==    still reachable: 44,676 bytes in 224 blocks
==5219==                       of which reachable via heuristic:
==5219==                         newarray           : 832 bytes in 16 blocks
==5219==         suppressed: 0 bytes in 0 blocks
==5219== 
==5219== For counts of detected and suppressed errors, rerun with: -v
==5219== ERROR SUMMARY: 18 errors from 18 contexts (suppressed: 0 from 0)

一些错误是:

==5219== 2,048 bytes in 1 blocks are still reachable in loss record 240 of 242
==5219==    at 0x402E2EC: realloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==5219==    by 0x5F7C151: g_realloc (in /lib/i386-linux-gnu/libglib-2.0.so.0.4600.2)
==5219==    by 0x5F06BCB: g_value_register_transform_func (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x5F08D6A: ??? (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x5ED9A2D: ??? (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x400EDCF: call_init.part.0 (dl-init.c:72)
==5219==    by 0x400EEDF: call_init (dl-init.c:30)
==5219==    by 0x400EEDF: _dl_init (dl-init.c:120)
==5219==    by 0x4000ACE: ??? (in /lib/i386-linux-gnu/ld-2.21.so)

==5219== 8 bytes in 1 blocks are possibly lost in loss record 95 of 242
==5219==    at 0x402E0D8: calloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==5219==    by 0x5F7C0DA: g_malloc0 (in /lib/i386-linux-gnu/libglib-2.0.so.0.4600.2)
==5219==    by 0x5EFC587: ??? (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x5F011B8: g_type_register_fundamental (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x5EE929E: ??? (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x5ED9A1E: ??? (in /usr/lib/i386-linux-gnu/libgobject-2.0.so.0.4600.2)
==5219==    by 0x400EDCF: call_init.part.0 (dl-init.c:72)
==5219==    by 0x400EEDF: call_init (dl-init.c:30)
==5219==    by 0x400EEDF: _dl_init (dl-init.c:120)
==5219==    by 0x4000ACE: ??? (in /lib/i386-linux-gnu/ld-2.21.so)

完整日志文件:http://pastebin.com/DQxQtnzK

我该如何解决这个问题？我该怎么办？

Answer 1

泄漏不是来自您的代码

^{以最少的编辑转录评论。}

Add suppressions; they're 'leaks' caused by the startup code that can't be fixed by you and probably won't be fixed by the developers of the C++ runtime. This is an extensive problem on Mac OS X. There are typically many allocations and a few tens of kilobytes of memory that are allocated by the startup code. (Options include --gen-suppressions=all and --suppressions=suppressions-file.)

本次征集评论:

FATAL: can't open suppressions file "suppressions-file"

哪个得到了还击(因为我发表评论时时间紧迫):

Read the manual. You use --gen-suppressions=all to generate the suppressions […]. Then edit the file (there's a placeholder where you're supposed to put an ID/name for each suppression entry). Then you can use the file in subsequent runs with --suppressions=name-you-created. You may need --show-leak-kinds=all, and maybe some others, too (-leak-check=full, for example). Use valgrind --help, but be aware that the output is fairly extensive.

工作示例 — Mac OS X 10.11.4

来源(mincpp.cpp)

int main() { return 0; }

编译

g++ -O3 -g -std=c++11 mincpp.cpp -o mincpp

(我通常会使用更多的警告选项，但是对于这段代码，真的没有必要。)

初始运行 valgrind

$ valgrind mincpp
==69167== Memcheck, a memory error detector
==69167== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==69167== Using Valgrind-3.12.0.SVN and LibVEX; rerun with -h for copyright info
==69167== Command: mincpp
==69167== 
--69167-- UNKNOWN fcntl 97!
--69167-- UNKNOWN fcntl 97! (repeated 2 times)
--69167-- UNKNOWN fcntl 97! (repeated 4 times)
--69167-- UNKNOWN fcntl 97! (repeated 8 times)
--69167-- UNKNOWN fcntl 97! (repeated 16 times)
--69167-- UNKNOWN fcntl 97! (repeated 32 times)
==69167== 
==69167== HEAP SUMMARY:
==69167==     in use at exit: 22,195 bytes in 190 blocks
==69167==   total heap usage: 255 allocs, 65 frees, 27,947 bytes allocated
==69167== 
==69167== LEAK SUMMARY:
==69167==    definitely lost: 4,120 bytes in 2 blocks
==69167==    indirectly lost: 2,288 bytes in 6 blocks
==69167==      possibly lost: 4,880 bytes in 45 blocks
==69167==    still reachable: 2,344 bytes in 12 blocks
==69167==         suppressed: 8,563 bytes in 125 blocks
==69167== Rerun with --leak-check=full to see details of leaked memory
==69167== 
==69167== For counts of detected and suppressed errors, rerun with: -v
==69167== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
$

对于这样一个最小的程序来说，有很多泄漏!

未知的 fcntl 消息很烦人，但似乎“几乎无害”；我可能需要再次重建 valgrind。

生成抑制

$ valgrind --gen-suppressions=all --leak-check=full --show-leak-kinds=all mincpp
==69211== Memcheck, a memory error detector
==69211== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==69211== Using Valgrind-3.12.0.SVN and LibVEX; rerun with -h for copyright info
==69211== Command: mincpp
==69211== 
--69211-- UNKNOWN fcntl 97!
--69211-- UNKNOWN fcntl 97! (repeated 2 times)
--69211-- UNKNOWN fcntl 97! (repeated 4 times)
--69211-- UNKNOWN fcntl 97! (repeated 8 times)
--69211-- UNKNOWN fcntl 97! (repeated 16 times)
--69211-- UNKNOWN fcntl 97! (repeated 32 times)
==69211== 
==69211== HEAP SUMMARY:
==69211==     in use at exit: 22,195 bytes in 190 blocks
==69211==   total heap usage: 255 allocs, 65 frees, 27,947 bytes allocated
==69211== 
==69211== 24 bytes in 1 blocks are still reachable in loss record 5 of 62
==69211==    at 0x1000071FC: malloc_zone_malloc (vg_replace_malloc.c:304)
==69211==    by 0x1005DC1E4: _read_images (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005E19EB: object_setClass (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DABC7: gc_init (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DA8C1: preopt_init (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DA5CA: map_images_nolock (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005ECC6C: batchFinalizeOnTwoThreads(_malloc_zone_t*, void (*)(auto_zone_cursor*, void (*)(void*, void*), void*), auto_zone_cursor*, unsigned long) (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x7FFF5FC047CF: dyld::notifyBatchPartial(dyld_image_states, bool, char const* (*)(dyld_image_states, unsigned int, dyld_image_info const*)) (in /usr/lib/dyld)
==69211==    by 0x7FFF5FC04516: dyld::registerImageStateBatchChangeHandler(dyld_image_states, char const* (*)(dyld_image_states, unsigned int, dyld_image_info const*)) (in /usr/lib/dyld)
==69211==    by 0x10023789D: dyld_register_image_state_change_handler (in /usr/lib/system/libdyld.dylib)
==69211==    by 0x1005D907B: _objc_init (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1001DFC93: _os_object_init (in /usr/lib/system/libdispatch.dylib)
==69211== 
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc_zone_malloc
   fun:_read_images
   fun:object_setClass
   fun:gc_init
   fun:preopt_init
   fun:map_images_nolock
   fun:_ZL25batchFinalizeOnTwoThreadsP14_malloc_zone_tPFvP16auto_zone_cursorPFvPvS3_ES3_ES2_m
   fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoE
   fun:_ZN4dyld36registerImageStateBatchChangeHandlerE17dyld_image_statesPFPKcS0_jPK15dyld_image_infoE
   fun:dyld_register_image_state_change_handler
   fun:_objc_init
   fun:_os_object_init
}
==69211== 24 bytes in 1 blocks are still reachable in loss record 6 of 62
==69211==    at 0x1000071FC: malloc_zone_malloc (vg_replace_malloc.c:304)
==69211==    by 0x1005DC1E4: _read_images (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005E19EB: object_setClass (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DCC96: NXHashInsert (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DB9B8: _read_images (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005DA5DA: map_images_nolock (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1005ECC6C: batchFinalizeOnTwoThreads(_malloc_zone_t*, void (*)(auto_zone_cursor*, void (*)(void*, void*), void*), auto_zone_cursor*, unsigned long) (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x7FFF5FC047CF: dyld::notifyBatchPartial(dyld_image_states, bool, char const* (*)(dyld_image_states, unsigned int, dyld_image_info const*)) (in /usr/lib/dyld)
==69211==    by 0x7FFF5FC04516: dyld::registerImageStateBatchChangeHandler(dyld_image_states, char const* (*)(dyld_image_states, unsigned int, dyld_image_info const*)) (in /usr/lib/dyld)
==69211==    by 0x10023789D: dyld_register_image_state_change_handler (in /usr/lib/system/libdyld.dylib)
==69211==    by 0x1005D907B: _objc_init (in /usr/lib/libobjc.A.dylib)
==69211==    by 0x1001DFC93: _os_object_init (in /usr/lib/system/libdispatch.dylib)
==69211== 
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc_zone_malloc
   fun:_read_images
   fun:object_setClass
   fun:NXHashInsert
   fun:_read_images
   fun:map_images_nolock
   fun:_ZL25batchFinalizeOnTwoThreadsP14_malloc_zone_tPFvP16auto_zone_cursorPFvPvS3_ES3_ES2_m
   fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoE
   fun:_ZN4dyld36registerImageStateBatchChangeHandlerE17dyld_image_statesPFPKcS0_jPK15dyld_image_infoE
   fun:dyld_register_image_state_change_handler
   fun:_objc_init
   fun:_os_object_init
}
…
==69211== LEAK SUMMARY:
==69211==    definitely lost: 4,120 bytes in 2 blocks
==69211==    indirectly lost: 2,288 bytes in 6 blocks
==69211==      possibly lost: 4,880 bytes in 45 blocks
==69211==    still reachable: 2,344 bytes in 12 blocks
==69211==         suppressed: 8,563 bytes in 125 blocks
==69211== 
==69211== For counts of detected and suppressed errors, rerun with: -v
==69211== ERROR SUMMARY: 6 errors from 6 contexts (suppressed: 12 from 12)
$

有时，我为一些数字 NN 添加 --num-callers=NN，但在我的构建中默认值似乎是 12(在早期版本中更少) ，我认为)，这就足够了。

在文件 min.suppressions 中生成抑制

$ valgrind --gen-suppressions=all --leak-check=full --show-leak-kinds=all mincpp 2>./min.suppressions
$ 

编辑min.suppressions

删除以== 和-- 开头的行；剩下的就是压制。为抑制添加名称。最终结果类似于:

{
   Mac-OSX-10.11.4-GCC-5.3.0-C++-Suppressions-001
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc_zone_malloc
   fun:_read_images
   fun:object_setClass
   fun:gc_init
   fun:preopt_init
   fun:map_images_nolock
   fun:_ZL25batchFinalizeOnTwoThreadsP14_malloc_zone_tPFvP16auto_zone_cursorPFvPvS3_ES3_ES2_m
   fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoE
   fun:_ZN4dyld36registerImageStateBatchChangeHandlerE17dyld_image_statesPFPKcS0_jPK15dyld_image_infoE
   fun:dyld_register_image_state_change_handler
   fun:_objc_init
   fun:_os_object_init
}
{
   Mac-OSX-10.11.4-GCC-5.3.0-C++-Suppressions-002
   Memcheck:Leak
   match-leak-kinds: reachable
   fun:malloc_zone_malloc
   fun:_read_images
   fun:object_setClass
   fun:NXHashInsert
   fun:_read_images
   fun:map_images_nolock
   fun:_ZL25batchFinalizeOnTwoThreadsP14_malloc_zone_tPFvP16auto_zone_cursorPFvPvS3_ES3_ES2_m
   fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoE
   fun:_ZN4dyld36registerImageStateBatchChangeHandlerE17dyld_image_statesPFPKcS0_jPK15dyld_image_infoE
   fun:dyld_register_image_state_change_handler
   fun:_objc_init
   fun:_os_object_init
}
…
{
   Mac-OSX-10.11.4-GCC-5.3.0-C++-Suppressions-021
   Memcheck:Leak
   match-leak-kinds: definite
   fun:malloc_zone_memalign
   fun:_ZL11addSubclassP10objc_classS0_
   fun:_ZL12realizeClassP10objc_class
   fun:_ZL12realizeClassP10objc_class
   fun:_ZN4dyldL12notifySingleE17dyld_image_statesPK11ImageLoader
   fun:_ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextEjRNS_21InitializerTimingListERNS_15UninitedUpwardsE
   fun:_ZN11ImageLoader19processInitializersERKNS_11LinkContextEjRNS_21InitializerTimingListERNS_15UninitedUpwardsE
   fun:_ZN11ImageLoader19processInitializersERKNS_11LinkContextEjRNS_21InitializerTimingListERNS_15UninitedUpwardsE
   fun:_ZN11ImageLoader15runInitializersERKNS_11LinkContextERNS_21InitializerTimingListE
   fun:_ZN4dyld24initializeMainExecutableEv
   fun:_ZN4dyld5_mainEPK12macho_headermiPPKcS5_S5_Pm
   fun:_ZN13dyldbootstrap5startEPK12macho_headeriPPKclS2_Pm
}

使用 --suppressions=./min.suppressions 重新运行

$ valgrind --suppressions=./min.suppressions mincpp
==72028== Memcheck, a memory error detector
==72028== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==72028== Using Valgrind-3.12.0.SVN and LibVEX; rerun with -h for copyright info
==72028== Command: mincpp
==72028== 
--72028-- UNKNOWN fcntl 97!
--72028-- UNKNOWN fcntl 97! (repeated 2 times)
--72028-- UNKNOWN fcntl 97! (repeated 4 times)
--72028-- UNKNOWN fcntl 97! (repeated 8 times)
--72028-- UNKNOWN fcntl 97! (repeated 16 times)
--72028-- UNKNOWN fcntl 97! (repeated 32 times)
==72028== 
==72028== HEAP SUMMARY:
==72028==     in use at exit: 22,195 bytes in 190 blocks
==72028==   total heap usage: 255 allocs, 65 frees, 27,947 bytes allocated
==72028== 
==72028== LEAK SUMMARY:
==72028==    definitely lost: 0 bytes in 0 blocks
==72028==    indirectly lost: 0 bytes in 0 blocks
==72028==      possibly lost: 0 bytes in 0 blocks
==72028==    still reachable: 0 bytes in 0 blocks
==72028==         suppressed: 22,195 bytes in 190 blocks
==72028== 
==72028== For counts of detected and suppressed errors, rerun with: -v
==72028== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
$

这表明先前报告的错误现在已被抑制。