From 7083ac7290a0c37a45494437a45441112f3cc36c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marek=20Ol=C5=A1=C3=A1k?= Date: Tue, 24 Apr 2018 17:01:35 -0400 Subject: [PATCH] util/u_queue: fix a deadlock in util_queue_finish MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Cc: 18.0 18.1 Reviewed-by: Nicolai Hähnle --- src/util/u_queue.c | 9 +++++++++ src/util/u_queue.h | 1 + 2 files changed, 10 insertions(+) diff --git a/src/util/u_queue.c b/src/util/u_queue.c index dba23f96456..da513fd9cc5 100644 --- a/src/util/u_queue.c +++ b/src/util/u_queue.c @@ -311,6 +311,7 @@ util_queue_init(struct util_queue *queue, goto fail; (void) mtx_init(&queue->lock, mtx_plain); + (void) mtx_init(&queue->finish_lock, mtx_plain); queue->num_queued = 0; cnd_init(&queue->has_queued_cond); @@ -398,6 +399,7 @@ util_queue_destroy(struct util_queue *queue) cnd_destroy(&queue->has_space_cond); cnd_destroy(&queue->has_queued_cond); + mtx_destroy(&queue->finish_lock); mtx_destroy(&queue->lock); free(queue->jobs); free(queue->threads); @@ -529,6 +531,12 @@ util_queue_finish(struct util_queue *queue) util_barrier_init(&barrier, queue->num_threads); + /* If 2 threads were adding jobs for 2 different barries at the same time, + * a deadlock would happen, because 1 barrier requires that all threads + * wait for it exclusively. + */ + mtx_lock(&queue->finish_lock); + for (unsigned i = 0; i < queue->num_threads; ++i) { util_queue_fence_init(&fences[i]); util_queue_add_job(queue, &barrier, &fences[i], util_queue_finish_execute, NULL); @@ -538,6 +546,7 @@ util_queue_finish(struct util_queue *queue) util_queue_fence_wait(&fences[i]); util_queue_fence_destroy(&fences[i]); } + mtx_unlock(&queue->finish_lock); util_barrier_destroy(&barrier); diff --git a/src/util/u_queue.h b/src/util/u_queue.h index d49f713e6ad..d702c4bce8d 100644 --- a/src/util/u_queue.h +++ b/src/util/u_queue.h @@ -200,6 +200,7 @@ struct util_queue_job { /* Put this into your context. */ struct util_queue { const char *name; + mtx_t finish_lock; /* only for util_queue_finish */ mtx_t lock; cnd_t has_queued_cond; cnd_t has_space_cond; -- 2.30.2