Re: [Boost-bugs] [Boost C++ Libraries] #5727: race condition between ~basic_condition_variable() and notify_all()

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #5727: race condition between ~basic_condition_variable() and notify_all()
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-12-02 23:54:03

#5727: race condition between ~basic_condition_variable() and notify_all()
-------------------------------------+--------------------------------------
  Reporter:  sbear.powell@…          |       Owner:  anthonyw
      Type:  Bugs                    |      Status:  new     
 Milestone:  To Be Determined        |   Component:  thread  
   Version:  Boost 1.46.1            |    Severity:  Problem 
Resolution:                          |    Keywords:          
-------------------------------------+--------------------------------------

Comment (by viboes):

 I'm surely misunderstanding your code


 {{{
 void foo() {
     condition_variable notifier;
     mutex m, m2;
     mutex::scoped_lock lock(m); //1
     bool done=false;
     thread t([&]{
         mutex::scoped_lock lock(m); //2
         done = true;
         lock.unlock();
         notifier.notify_all();
     });
     while(!done) notifier.wait(lock); //3
 }
 }}}


 Doesn't this code deadlock. In 1 foo owns the lock m. In 2 the lambda
 thread is blocked until the lock variable exits his scope (at the end of
 foo). In 3 As done is false thread foo waits for notifier, which can not
 be notified by the lambda as blocked.

 What am I missing?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5727#comment:1>
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