http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60966
--- Comment #2 from Thomas Sanchez <thomas.sanchz at gmail dot com> --- Hi, Thanks for your answer, (In reply to Jonathan Wakely from comment #1) > (It would be easier to make sense of this if the line numbers in your gdb > and valgrind output matched the code on github.) > Indeed, sorry, I added some debug that I did not commit, I'll create a branch with this version tomorrow. The important things is that it is always on set_value() that I hang. > Blocking in pthread_once could be a symptom of using an invalid > pthread_once_t that has already been destroyed, and the valgrind output > indeed shows that the set_value() call is being made on a shared state that > has been deleted already, when the promise that owned it went out of scope. > It looks like that shouldn't have happened though. > I reached the same conclusion. > Is it possible the task is getting run twice by the thread pool, so on the > second run the reference to the promise is dangling? Hum, since I'm using boost::asio (boost::asio::io_service::post/dispatch), I do hope that this is not the case, but this is something I can check. I don't remember however having a double log. > > When the process hangs could you use gdb to print &promise in both threads, > where it is waiting on future::get and promise::set_value? The values should > be the same, since the closure running in the thread pool should have a > reference to the local object in the waiting thread. Will do. > > Replacing the lambda in the destructor with a call to a member function > would help to rule out a code generation problem due to the lambda, which is > a remote possibility. > Will do. > Can the problem be reproduced by one of the unit tests in the httpp repo? > Unfortunately I don't have anything to reproduce the bug each time. I'll try something tomorrow. > > N.B. the std::move in Manager::cancelConnection is redundant, the return > value from cancel_connection is already an rvalue. Yes, I know, the problem is I have some hard time to avoid doing this as it is more for me and what I expect the compiler to do or the semantics I want the code to have :)
