c – gdb来调试valgrind未检测到的双重释放(？)
发布时间：2020-12-16 09:29:59 所属栏目：百科 来源：网络整理
导读：大约每三次我运行我的程序,malloc报告一个双重自由错误;例如 myprogram(703,0xb06d9000) malloc: *** error for object 0x17dd0240: double free*** set a breakpoint in malloc_error_break to debug 我通过valgrind运行了相同的代码十几次,但它从未报告过
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大约每三次我运行我的程序,malloc报告一个双重自由错误;例如
myprogram(703,0xb06d9000) malloc: *** error for object 0x17dd0240: double free *** set a breakpoint in malloc_error_break to debug 我通过valgrind运行了相同的代码十几次,但它从未报告过双重免费. 我通过gdb在malloc_error_break上使用断点运行代码,并且(当错误发生时)错误始终在标准c库函数中报告.我隔离了父函数并在测试单元中对其进行了调整但没有错误. 我认为父函数/标准c库不应该受到责备,它只是释放它分配的东西,但父程序中的一些其他函数被释放. 我已经尝试查找哪个对象是双重释放但我的gdb技能不能找到第一个被释放的对象.请帮助我找到哪个对象导致第一个免费,另外任何帮助,为什么我的程序生成此错误.谢谢. 父函数归结为： int i;
double px,py;
int start,finish;
std::string comment;
std::vector<double> x,y;
std::fstream myfile;
myfile.open("filename.txt",std::ios_base::in);
// Read header
std::getline(myfile,comment);
// Read data
while(!myfile.eof())
{
myfile >> comment >> start >> comment >> finish;
for(i = 0; i <= finish-start; i++)
{
myfile >> px >> py; // double free here
x.push_back(px);
y.push_back(py);
}
}
编辑： Comment: My Data start 33 end 36 10.2 139.0076 9.22616 141.584 8.62802 141.083 8.87098 141.813 start 33 end 35 300.354 405 301.698 404.029 303.369 403.953 start 33 end 35 336.201 148.07 334.616 147.243 334.735 146.09 来自gdb的回溯是 (gdb) backtrace #0 0x93c2d4a9 in malloc_error_break () #1 0x93c28497 in szone_error () #2 0x93b52503 in szone_free () #3 0x93b5236d in free () #4 0x93b51f24 in localeconv_l () #5 0x93c18163 in strtod_l$UNIX2003 () #6 0x93c192e0 in strtod$UNIX2003 () #7 0x919b76e8 in std::__convert_to_v<double> () #8 0x919983cf in std::num_get<char,std::istreambuf_iterator<char,std::char_traits<char> > >::do_get () #9 0x91991671 in std::num_get<char,std::char_traits<char> > >::get () #10 0x9198d2dc in std::istream::operator>> () 重申一点,我需要帮助才能找到第一次释放的对象,我对重构这个函数的代码并不感兴趣 – 我认为这不会导致问题;除非你能在其中找到灾难性的东西. 编辑：更改了示例代码. 解决方法
你似乎在使用Mac OSX(你应该泄露这个事实:-)
有several environment variables可以帮助您调试堆损坏. 特别是,MallocStackLoggingNoCompact看起来非常有前景. 这是我看到的： $cat t.c
int main()
{
char *p = strdup("hello");
free(p);
free(p);
return 0;
}
$gdb ./a.out
GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:11:58 UTC 2009)
Copyright 2004 Free Software Foundation,Inc.
GDB is free software,covered by the GNU General Public License,and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-apple-darwin"...Reading symbols for shared libraries ... done
(gdb) set env MallocStackLoggingNoCompact 1
(gdb) b malloc_error_break
Breakpoint 1 at 0x13f44a9
(gdb) r
Starting program: /Users/emp-russian/a.out
bash(22634) malloc: recording malloc stacks to disk using standard recorder
bash(22634) malloc: stack logging compaction turned off; size of log files on disk can increase rapidly
bash(22634) malloc: process 22536 no longer exists,stack logs deleted from /tmp/stack-logs.22536.a.out.8D3VZO
bash(22634) malloc: stack logs being written into /tmp/stack-logs.22634.bash.kjFTGa
arch(22634) malloc: recording malloc stacks to disk using standard recorder
arch(22634) malloc: stack logging compaction turned off; size of log files on disk can increase rapidly
arch(22634) malloc: stack logs deleted from /tmp/stack-logs.22634.bash.kjFTGa
arch(22634) malloc: stack logs being written into /tmp/stack-logs.22634.arch.8L8iLX
Reading symbols for shared libraries ++. done
Breakpoint 1 at 0x909b54a9
a.out(22634) malloc: recording malloc stacks to disk using standard recorder
a.out(22634) malloc: stack logging compaction turned off; size of log files on disk can increase rapidly
a.out(22634) malloc: stack logs deleted from /tmp/stack-logs.22634.arch.8L8iLX
a.out(22634) malloc: stack logs being written into /tmp/stack-logs.22634.a.out.s1qQRw
a.out(22634) malloc: *** error for object 0x100080: double free
*** set a breakpoint in malloc_error_break to debug
Breakpoint 1,0x909b54a9 in malloc_error_break ()
(gdb) shell ls -l /tmp/stack-logs.22634.a.out.s1qQRw
total 16
-rw------- 1 emp-russian wheel 96 Sep 12 09:42 stack-logs.index
-rw------- 1 emp-russian wheel 208 Sep 12 09:42 stack-logs.stacks
(gdb) shell malloc_history 22634 0x100080
我们实际上并不关心历史的第一部分： Call [2] [arg=24]: thread_a0103720 |_dyld_start | dyldbootstrap::start(mach_header const*,int,char const**,long) | dyld::_main(mach_header const*,unsigned long,char const**) | dyld::initializeMainExecutable() | ImageLoader::runInitializers(ImageLoader::LinkContext const&) | ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&,unsigned int) | ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&,unsigned int) | ImageLoaderMachO::doModInitFunctions(ImageLoader::LinkContext const&) | libSystem_initializer | __keymgr_initializer | _dyld_register_func_for_add_image | dyld::registerAddCallback(void (*)(mach_header const*,long)) | dwarf2_unwind_dyld_add_image_hook | calloc | _malloc_initialize | malloc_set_zone_name | malloc_zone_malloc | __disk_stack_logging_log_stack | reap_orphaned_log_files | opendir$INODE64$UNIX2003 | __opendir2$INODE64$UNIX2003 | telldir$INODE64$UNIX2003 | malloc | malloc_zone_malloc Call [4] [arg=0]: thread_a0103720 |_dyld_start | dyldbootstrap::start(mach_header const*,long)) | dwarf2_unwind_dyld_add_image_hook | calloc | _malloc_initialize | malloc_set_zone_name | malloc_zone_malloc | __disk_stack_logging_log_stack | reap_orphaned_log_files | closedir$UNIX2003 | _reclaim_telldir | free | malloc_zone_free 但这里有趣的是： Call [2] [arg=6]: thread_a0103720 |0x1 | start | main | strdup | malloc | malloc_zone_malloc Call [4] [arg=0]: thread_a0103720 |0x1 | start | main | free | malloc_zone_free Call [4] [arg=0]: thread_a0103720 |0x1 | start | main | free | malloc_zone_free （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |