[Boost-users] [Thread] program crashes from time to time when deleting unique_future<void>

Subject: [Boost-users] [Thread] program crashes from time to time when deleting unique_future<void>
From: Soderback, Johan (Johan.Soderback_at_[hidden])
Date: 2011-11-21 11:40:04

Hi,

I have a small example program that crashes from time to time.
I would appreciate some help to understand why.

In function run() executed on the main thread I create a packaged_task (pt), put it in a queue (_q) and wait for it to get executed (fu.get()).
In another thread the tasks are executed when the queue _q is populated.
The task I'm running always throws/rethrows intentionally.

It results (from time to time) in an access violation when the unique_future, fu, is deleted.
See the stack trace at the bottom.

Anybody see any flaws in this design?

I have tried 1.47.0 and 1.48.0,  MSVC 2005.

Here's the code.

*****************************************************

#include <boost/exception/all.hpp>
#include <boost/thread.hpp>
#include <sstream>
#include <iostream>

struct Exception
  : public virtual std::exception
  , public virtual boost::exception
{
};

struct TheException  : public virtual Exception {};

void throwf()
{
  try
  {
    BOOST_THROW_EXCEPTION(TheException());
  }
  catch (...)
  {
    boost::current_exception_diagnostic_information();
    throw;
  }
}

struct Test
{
  Test()
  {
    _t.reset(new boost::thread(boost::bind(&Test::executor, this)));
  }

  ~Test()
  {
    _t->join();
  }

  void executor()
  {
    for (;;)
    {
      boost::unique_lock<boost::mutex> lk(_mx);

      while(_q.empty())
      {
        _cv.wait(lk);
      }

      boost::shared_ptr< boost::packaged_task<void> > pt = _q.front();
      _q.pop_front();
      lk.unlock();

      (*pt)();
    }
  }

  void run()
  {
    for (;;)
    {
      const int N = 20000;
      for (int j = 0; j < N; ++j)
      {
        boost::shared_ptr< boost::packaged_task<void> > pt(new boost::packaged_task<void>(throwf));
        boost::unique_future<void> fu = pt->get_future();

        {
          boost::unique_lock<boost::mutex> lk(_mx);
          _q.push_back(pt);
          pt.reset();
        }

        _cv.notify_one();

        try
        {
          fu.get();
          assert(false);
        }
        catch (const TheException& )
        {
        }
        catch (const boost::exception& )
        {
          assert(false);
        }
        catch (...) {
          assert(false);
        }
      }
      std::cout << ".";
    }
  }

private:
  boost::mutex _mx;
  std::list< boost::shared_ptr< boost::packaged_task<void> > > _q;
  boost::shared_ptr<boost::thread> _t;
  boost::condition_variable_any _cv;
};

int main(int, char*)
{
  Test test;
  test.run();
}

*****************************************************

Here is the callstack, program terminated with access violation.

Unhandled exception at 0x0043196b in crasher.exe: 0xC0000005: Access violation reading location 0xdddddded.

>                 crasher.exe!boost::exception_detail::refcount_ptr<boost::exception_detail::error_info_container>::release()  Line 78 + 0x18 bytes       C++
                  crasher.exe!boost::exception_detail::refcount_ptr<boost::exception_detail::error_info_container>::~refcount_ptr<boost::exception_detail::error_info_container>()  Line 35        C++
                 crasher.exe!boost::exception::~exception()  Line 278 + 0xb bytes                C++
                 crasher.exe!boost::exception_detail::clone_impl<TheException>::`vbase destructor'()  + 0x41 bytes          C++
                 crasher.exe!boost::exception_detail::clone_impl<TheException>::`scalar deleting destructor'()  + 0x2b bytes   C++
                 crasher.exe!boost::checked_delete<boost::exception_detail::clone_base const >(const boost::exception_detail::clone_base * x=0x006f7d10)  Line 34 + 0x35 bytes  C++
                 crasher.exe!boost::detail::sp_counted_impl_p<boost::exception_detail::clone_base const >::dispose()  Line 78 + 0xc bytes       C++
                 crasher.exe!boost::detail::sp_counted_base::release()  Line 102 + 0xf bytes  C++
                 crasher.exe!boost::detail::shared_count::~shared_count()  Line 309             C++
                 crasher.exe!boost::shared_ptr<boost::exception_detail::clone_base const >::~shared_ptr<boost::exception_detail::clone_base const >()  + 0x2e bytes                 C++
                 crasher.exe!boost::exception_ptr::~exception_ptr()  + 0x2b bytes               C++
                 crasher.exe!boost::detail::future_object_base::~future_object_base()  Line 106 + 0x9c bytes                 C++
                 crasher.exe!boost::detail::future_object<void>::~future_object<void>()  + 0x2b bytes    C++
                 crasher.exe!boost::detail::task_base<void>::~task_base<void>()  + 0x2b bytes             C++
                 crasher.exe!boost::detail::task_object<void,void (__cdecl*)(void)>::~task_object<void,void (__cdecl*)(void)>()  + 0x2b bytes      C++
                 crasher.exe!boost::detail::task_object<void,void (__cdecl*)(void)>::`scalar deleting destructor'()  + 0x2b bytes                 C++
                 crasher.exe!boost::checked_delete<boost::detail::task_object<void,void (__cdecl*)(void)> >(boost::detail::task_object<void,void (__cdecl*)(void)> * x=0x006f7b10)  Line 34 + 0x34 bytes        C++
                 crasher.exe!boost::detail::sp_counted_impl_p<boost::detail::task_object<void,void (__cdecl*)(void)> >::dispose()  Line 78 + 0xc bytes                 C++
                 crasher.exe!boost::detail::sp_counted_base::release()  Line 102 + 0xf bytes  C++
                 crasher.exe!boost::detail::shared_count::~shared_count()  Line 309             C++
                 crasher.exe!boost::shared_ptr<boost::detail::future_object<void> >::~shared_ptr<boost::detail::future_object<void> >()  + 0x2e bytes         C++
                 crasher.exe!boost::unique_future<void>::~unique_future<void>()  Line 644 + 0x2b bytes                 C++
                 crasher.exe!Test::run()  Line 95 + 0xc bytes          C++
                 crasher.exe!main(int __formal=1, int __formal=1)  Line 112      C++
                 crasher.exe!__tmainCRTStartup()  Line 597 + 0x19 bytes          C
                 crasher.exe!mainCRTStartup()  Line 414                C
                 kernel32.dll!7c817067()
                 [Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll]

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