helgrind: dubious: associated lock is not held by any thread: void boost::asio::detail::posix_event::signal_and_unlock<boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex> >(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (posix_event.hpp:62)

[Daniel van Vugt]

helgrind: dubious: associated lock is not held by any thread: void boost::asio::detail::posix_event::signal_and_unlock<boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex> >(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (posix_event.hpp:62)

This seems to happen repeatedly...

==21450== ----------------------------------------------------------------
==21450==
==21450== Thread #10: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==21450== at 0x4C2D518: ??? (in /usr/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==21450== by 0x52ECFFA: void boost::asio::detail::posix_event::signal_and_unlock<boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex> >(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (posix_event.hpp:62)
==21450== by 0x52E9AFC: boost::asio::detail::task_io_service::wake_one_idle_thread_and_unlock(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (task_io_service.ipp:509)
==21450== by 0x52E9B2E: boost::asio::detail::task_io_service::wake_one_thread_and_unlock(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (task_io_service.ipp:518)
==21450== by 0x52E98EE: boost::asio::detail::task_io_service::do_run_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service_thread_info&, boost::system::error_code const&) (task_io_service.ipp:403)
==21450== by 0x52E9383: boost::asio::detail::task_io_service::run(boost::system::error_code&) (task_io_service.ipp:153)
==21450== by 0x52E9C8E: boost::asio::io_service::run() (io_service.ipp:59)
==21450== by 0x5319727: mir::frontend::BasicConnector::start()::{lambda()#1}::operator()() const (published_socket_connector.cpp:103)
==21450== by 0x531AEB9: void std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()>::_M_invoke<>(std::_Index_tuple<>) (functional:1732)
==21450== by 0x531AE06: std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()>::operator()() (functional:1720)
==21450== by 0x531AD9F: std::thread::_Impl<std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()> >::_M_run() (thread:115)
==21450== by 0x5E7776F: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.18)
==21450==

==21450== ----------------------------------------------------------------
==21450==
==21450== Thread #9: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==21450== at 0x4C2D518: ??? (in /usr/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==21450== by 0x52ECFFA: void boost::asio::detail::posix_event::signal_and_unlock<boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex> >(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (posix_event.hpp:62)
==21450== by 0x52E9AFC: boost::asio::detail::task_io_service::wake_one_idle_thread_and_unlock(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&) (task_io_service.ipp:509)
==21450== by 0x52E984B: boost::asio::detail::task_io_service::do_run_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service_thread_info&, boost::system::error_code const&) (task_io_service.ipp:384)
==21450== by 0x52E9383: boost::asio::detail::task_io_service::run(boost::system::error_code&) (task_io_service.ipp:153)
==21450== by 0x52E9C8E: boost::asio::io_service::run() (io_service.ipp:59)
==21450== by 0x5319727: mir::frontend::BasicConnector::start()::{lambda()#1}::operator()() const (published_socket_connector.cpp:103)
==21450== by 0x531AEB9: void std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()>::_M_invoke<>(std::_Index_tuple<>) (functional:1732)
==21450== by 0x531AE06: std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()>::operator()() (functional:1720)
==21450== by 0x531AD9F: std::thread::_Impl<std::_Bind_simple<mir::frontend::BasicConnector::start()::{lambda()#1} ()> >::_M_run() (thread:115)
==21450== by 0x5E7776F: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.18)
==21450== by 0x4C2EA06: ??? (in /usr/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==21450==

[Cemil Azizoglu (cemil-azizoglu)]

Could be a false positive. --> medium

[Daniel van Vugt (vanvugt)]

So long as helgrind has wrapped all your locking primitives (e.g. implements in terms of pthreads) then the Eraser algorithm it uses is very reliable and doesn't give false positives.

Although we have seen at least one such case where this happens -- std::atomic is not implemented in terms of locking primitives that helgrind understands. But std::atomic is the only case I'm aware of where Helgrind should give false positives.

Unfortunately, Helgrind was suggested so late in Mir's development that the code base was already full of a large number of races which will be very difficult to get on top of. And while we're not on top of it we can't automate it yet either.

[Cemil Azizoglu (cemil-azizoglu)]

I can't get this to happen. Can you? If so, how?

This is a year old. Perhaps it was fixed or that the code changed so much that it takes some more effort.

[Launchpad Janitor (janitor)]

[Expired for boost1.53 (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Mir because there has been no activity for 60 days.]