From a0a616720ade8b35171fc8755803ec123d0d98fc Mon Sep 17 00:00:00 2001 From: =?utf8?q?Nicolai=20H=C3=A4hnle?= Date: Sat, 9 Jul 2016 19:40:51 +0200 Subject: [PATCH] gallium/u_queue: guard fence->signalled checks with fence->mutex MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit I have seen a hang during application shutdown that could be explained by the following race condition which this patch fixes: 1. Worker thread enters util_queue_fence_signal, sets fence->signalled = true. 2. Main thread calls util_queue_job_wait, which returns immediately. 3. Main thread deletes the job and fence structures, leaving garbage behind. 4. Worker thread calls pipe_condvar_broadcast, which gets stuck forever because it is accessing garbage. Reviewed-by: Marek Olšák Reviewed-by: Edward O'Callaghan --- src/gallium/auxiliary/util/u_queue.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/src/gallium/auxiliary/util/u_queue.c b/src/gallium/auxiliary/util/u_queue.c index 627c08a524a..24293367ec8 100644 --- a/src/gallium/auxiliary/util/u_queue.c +++ b/src/gallium/auxiliary/util/u_queue.c @@ -41,9 +41,6 @@ util_queue_fence_signal(struct util_queue_fence *fence) void util_queue_job_wait(struct util_queue_fence *fence) { - if (fence->signalled) - return; - pipe_mutex_lock(fence->mutex); while (!fence->signalled) pipe_condvar_wait(fence->cond, fence->mutex); -- 2.30.2