调试boost ::线程应用，高误报率

问题描述

我编写了一个boost :: thread应用程序，其中我可能有一些竞争条件。我想调试这个程序。因此，我使用了以下valgrind工具：

1. halgrind


2. drd

不幸的是，他们有一个非常假的阳性率。所以使用真正简单的程序下面 valgrind --tool = drd 抱怨大约94错误，其中no应该是。所以与我的复杂程序，我得到大约15000错误。所以这真的很难找到实际的错误。

我可以用以下boost库1.46.0和1.47.0重现这种行为。并用valgrind 3.7.0 SVN和valgrind 3.8.0 SVN。操作系统我试过它在哪里Ubuntu 11.10和Mac OS X 10.7。编译器中的gcc 4.2.1和gcc 4.6.1。

  #include< iostream> 
 #include< boost / thread.hpp> 
 
 void run（）
 {
 //在这里做一些事情
} 
 
 int main（int argc，char * argv [ ]）
 {
 boost :: thread thread（run）; 
 thread.join（）; 
 std :: cerr<< main：done< std :: endl; 
 return 0; 
} 
; 
  

如何调试boost线程程序？是否有其他工具可能更适合？

解决方案

那个valgrind版本3.6.1后被打破。如果我使用valgrind 3.6.1一切正常。

这里来自的错误报告valgrind --tool = drd ：

  == 60767 == Thread 1：
 == 60767 ==以0x100026ec0大小8 
 == 60767 == at 0x2A316E：pthread_mutex_lock（在/usr/lib/system/libsystem_c.dylib中）
 == 60767 == by 0x2A82FA：_pthread_cond_wait（在/ usr / lib / system / libsystem_c .dylib）
 == 60767 == by 0x32A4E：boost :: condition_variable :: wait（boost :: unique_lock< boost :: mutex>&）（in /usr/local/lib/libboost_thread.dylib）
 == 60767 == by 0x2BE5A：boost :: thread :: join（）（在/usr/local/lib/libboost_thread.dylib）
 == 60767 == by 0x10000195C：main（in ./ playgroudThreads）
 == 60767 ==地址0x100026ec0在从0x100026e30的偏移144。分配上下文：
 == 60767 == at 0xC5B3：malloc（vg_replace_malloc.c：266）
 == 60767 == by 0x9968D：operator new（unsigned long）（在/ usr / lib / libstdc ++中。 6.0.9.dylib）
 == 60767 == by 0x1000069ED：boost :: detail :: thread_data< void（*）（）> * boost :: detail :: heap_new_impl< boost :: detail :: thread_data< ; void（*）（）>，void（*&）（）>（void（*&）（））（in ./playgroudThreads）
 == 60767 == by 0x100006A87： ：detail :: thread_data< void（*）（）> * boost :: detail :: heap_new& boost :: detail :: thread_data< void（*）（）> （*&）（））（in ./playgroudThreads）
 == 60767 == by 0x100006ACA：boost :: shared_ptr< boost :: detail :: thread_data_base> boost :: thread :: make_thread_info< void（*）（）>（void（*）（））（in ./playgroudThreads）
 == 60767 == by 0x100006B08：boost :: thread :: thread< void（*）（）>（void（*）（），boost :: disable_if< boost :: is_convertible< void（*&）（），boost :: detail :: thread_move_t& ;>，boost :: thread :: dummy *> :: type）（in ./playgroudThreads）
 == 60767 == by 0x100001950：main（in ./playgroudThreads）
 == 60767 ==其他段结束（线程2）
 == 60767 ==在0x2A7B68：thread_start（在/usr/lib/system/libsystem_c.dylib）
 == 60767 ==其他段结束）
 == 60767 == at 0x3E667A：mach_msg_trap（在/usr/lib/system/libsystem_kernel.dylib）
 == 60767 == by 0x3DED38：semaphore_create（在/ usr / lib / system / libsystem_kernel .dylib）
 == 60767 == by 0x2A50F7：new_sem_from_pool（在/usr/lib/system/libsystem_c.dylib）
 == 60767 == by 0x2A6199：_pthread_exit（在/ usr / lib / system /libsystem_c.dylib）
 == 60767 == by 0x2A48C9：_pthread_start（在/usr/lib/system/libsystem_c.dylib）
 == 60767 == by 0x2A7B74：thread_start（在/ usr / lib /system/libsystem_c.dylib）
  

解决方案

=http://valgrind.org/docs/manual/drd-manual.html =nofollow> DRD手册

p>

因此，如果DRD报告一个假阳性，在一个像你的无竞争程序，它有一个错误。

但是，我无法重现您报告的错误，在我的机器上（Archlinux / gcc 4.6.2 / valgrind 3.6.1 / boost 1.47）。

I have programmed a boost::thread application, where I might have some race conditions. I want to debug this program. Therefore I used the following valgrind tools:

1. halgrind
2. drd

unfortunately they have a very false positive rate. So with the really simple program below valgrind --tool=drd complains about 94 errors, where no should be. So with my complex program I get about 15000 errors. So it is really hard to find the actual error.

I could reproduce this behavior with the following boost libraries 1.46.0 and 1.47.0. And with valgrind 3.7.0 SVN and valgrind 3.8.0 SVN. The operating systems I tried it out where Ubuntu 11.10 and Mac OS X 10.7. The compiler where gcc 4.2.1 and gcc 4.6.1.

#include <iostream>
#include <boost/thread.hpp>

void run()
{
    //do some stuff here
}

int main(int argc, char* argv[])
{
    boost::thread thread(run);
    thread.join();
    std::cerr << "main: done" << std::endl;
    return 0;
}
;

How do you debug your boost thread programs? Are there other tools which might be better suited?

Solution

It seems that valgrind after version 3.6.1 is broken. If I use valgrind 3.6.1 everything works fine.

Here on error report from valgrind --tool=drd:

==60767== Thread 1:
==60767== Conflicting store by thread 1 at 0x100026ec0 size 8
==60767==    at 0x2A316E: pthread_mutex_lock (in /usr/lib/system/libsystem_c.dylib)
==60767==    by 0x2A82FA: _pthread_cond_wait (in /usr/lib/system/libsystem_c.dylib)
==60767==    by 0x32A4E: boost::condition_variable::wait(boost::unique_lock<boost::mutex>&) (in /usr/local/lib/libboost_thread.dylib)
==60767==    by 0x2BE5A: boost::thread::join() (in /usr/local/lib/libboost_thread.dylib)
==60767==    by 0x10000195C: main (in ./playgroudThreads)
==60767== Address 0x100026ec0 is at offset 144 from 0x100026e30. Allocation context:
==60767==    at 0xC5B3: malloc (vg_replace_malloc.c:266)
==60767==    by 0x9968D: operator new(unsigned long) (in /usr/lib/libstdc++.6.0.9.dylib)
==60767==    by 0x1000069ED: boost::detail::thread_data<void (*)()>* boost::detail::heap_new_impl<boost::detail::thread_data<void (*)()>, void (*&)()>(void (*&)()) (in ./playgroudThreads)
==60767==    by 0x100006A87: boost::detail::thread_data<void (*)()>* boost::detail::heap_new<boost::detail::thread_data<void (*)()>, void (*)()>(void (*&)()) (in ./playgroudThreads)
==60767==    by 0x100006ACA: boost::shared_ptr<boost::detail::thread_data_base> boost::thread::make_thread_info<void (*)()>(void (*)()) (in ./playgroudThreads)
==60767==    by 0x100006B08: boost::thread::thread<void (*)()>(void (*)(), boost::disable_if<boost::is_convertible<void (*&)(), boost::detail::thread_move_t<void (*)()> >, boost::thread::dummy*>::type) (in ./playgroudThreads)
==60767==    by 0x100001950: main (in ./playgroudThreads)
==60767== Other segment start (thread 2)
==60767==    at 0x2A7B68: thread_start (in /usr/lib/system/libsystem_c.dylib)
==60767== Other segment end (thread 2)
==60767==    at 0x3E667A: mach_msg_trap (in /usr/lib/system/libsystem_kernel.dylib)
==60767==    by 0x3DED38: semaphore_create (in /usr/lib/system/libsystem_kernel.dylib)
==60767==    by 0x2A50F7: new_sem_from_pool (in /usr/lib/system/libsystem_c.dylib)
==60767==    by 0x2A6199: _pthread_exit (in /usr/lib/system/libsystem_c.dylib)
==60767==    by 0x2A48C9: _pthread_start (in /usr/lib/system/libsystem_c.dylib)
==60767==    by 0x2A7B74: thread_start (in /usr/lib/system/libsystem_c.dylib)

解决方案

From DRD manual

So DRD does not have any false positive if the implementation uses just POSIX threads and not non-POSIX stuff like Linux's futex.

Therefore, if DRD reports a false positive, on a race-free program like yours, it has a bug. It is not supposed to have false positives.

However, I could not reproduce the errors you reported, on my machine (Archlinux/ gcc 4.6.2 / valgrind 3.6.1 / boost 1.47).

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