Boost C++ Libraries: Ticket #9569: [windows] Upgrade lock is not acquired when previous upgrade lock releases if another read lock is present

status, component changed; owner set

viboes — Mon, 13 Jan 2014 22:01:05 GMT

owner set to viboes
status new → assigned
component None → thread

viboes — Wed, 26 Feb 2014 07:10:07 GMT

Hi,

Please could you try adding

        void release_shared_waiters(state_data old_state)
        {
            if(old_state.shared_waiting || old_state.exclusive_waiting)
            {
                BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[unlock_sem],old_state.shared_waiting + (old_state.exclusive_waiting?1:0),0)!=0);
            }
        }

and changing the implementation to

        void unlock_upgrade()
        {
            state_data old_state=state;
            for(;;)
            {
                state_data new_state=old_state;
                new_state.upgrade=false;
                bool const last_reader=!--new_state.shared_count;
                if(last_reader)
                {
                    if(new_state.exclusive_waiting)
                    {
                        --new_state.exclusive_waiting;
                        new_state.exclusive_waiting_blocked=false;
                    }
                    new_state.shared_waiting=0;
                }
                state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state);
                if(current_state==old_state)
                {
                    if(last_reader)
                    {
                        release_waiters(old_state);
                    }
                    else {
                        release_shared_waiters(old_state);
                    }
                    // #7720
                    //else {
                    //    release_waiters(old_state);
                    //}
                    break;
                }
                old_state=current_state;
            }
        }

Please could you also try the test in #7720?

milestone changed

viboes — Wed, 12 Mar 2014 23:03:27 GMT

milestone To Be Determined → Boost 1.57.0

summary changed

viboes — Sat, 06 Sep 2014 14:53:47 GMT

summary Upgrade lock is not acquired when previous upgrade lock releases if another read lock is present → [windows] Upgrade lock is not acquired when previous upgrade lock releases if another read lock is present

viboes — Tue, 16 Sep 2014 06:19:22 GMT

Any new on this issue?

viboes — Wed, 08 Oct 2014 05:36:12 GMT

https://github.com/boostorg/thread/commit/6f91af2154da808eb29de2e9e12c3e1774cdea31

status changed; resolution set

viboes — Sat, 11 Oct 2014 05:26:16 GMT

status assigned → closed
resolution → fixed