Re: [Boost-bugs] [Boost C++ Libraries] #3526: Data races in boost::thread detected by drd/helgrind

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3526: Data races in boost::thread detected by drd/helgrind
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-06-05 11:14:28

#3526: Data races in boost::thread detected by drd/helgrind
-------------------------------------+--------------------------------------
 Reporter:  m.strashun@…             |       Owner:  anthonyw
     Type:  Bugs                     |      Status:  new     
Milestone:  To Be Determined         |   Component:  thread  
  Version:  Boost Development Trunk  |    Severity:  Problem 
 Keywords:  valgrind,drd,threading   |  
-------------------------------------+--------------------------------------

Comment(by bvanassche@…):

 Replying to [comment:6 bvanassche@…]:
 > This is a real bug. With the current implementation it is possible that
 call_once() invokes its
 > second argument (Function f) twice. flag.epoch should be tested again
 after
 > detail::once_epoch_mutex has been locked, just like as when applying the
 double-checked
 > optimization to the singleton pattern.

 Please ignore the above comment -- I overlooked the
 pthread_mutex_scoped_lock statement near the beginning of call_once()
 which guarantees thread-safe updating of flag.epoch and also that f() is
 invoked by only one thread.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3526#comment:7>
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