调试boost :: thread应用程序,误报率高

Question

我编写了一个boost :: thread应用程序,我可能会遇到一些竞争条件.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,他们的假阳性率很高.因此,下面真正简单的程序valgrind --tool=drd抱怨94错误,其中不应该.因此,通过我复杂的程序,我得到大约15000个错误.所以很难找到实际的错误.

我可以使用以下boost库1.46.0和1.47.0重现此行为.并使用valgrind 3.7.0 SVN和valgrind 3.8.0 SVN.操作系统我尝试了Ubuntu 11.10和Mac OS X 10.7.编译器所在的gcc 4.2.1和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;
}
;

你如何调试你的boost程序？还有其他工具可能更适合吗？

解

似乎版本3.6.1之后的valgrind被破坏了.如果我使用valgrind 3.6.1一切正常.

这里的错误报告来自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)

Answer 1

来自DRD手册

数据竞争检测器发生之前的一个重要优点是它们不会报告任何误报。DRD 基于happens-before 算法。

因此，如果实现仅使用 POSIX 线程而不是 Linux 的 futex 等非 POSIX 内容，则 DRD 不会出现任何误报。

因此，如果 DRD 在像您这样的无竞争程序上报告误报，则它存在错误。它不应该有误报。

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