Mesa (master): util/u_queue: fix a use-before-initialization race for queue->threads

[Marek Olšák]

Module: Mesa
Branch: master
Commit: e93a141f64dc59a686e1815a34fad31dcc8545e3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e93a141f64dc59a686e1815a34fad31dcc8545e3

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Wed Jun  7 23:13:35 2017 +0200

util/u_queue: fix a use-before-initialization race for queue->threads

Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

---

 src/util/u_queue.c | 30 ++++++++++++++----------------
 src/util/u_queue.h |  1 -
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/util/u_queue.c b/src/util/u_queue.c
index 94fe2202a2..cb5903014e 100644
--- a/src/util/u_queue.c
+++ b/src/util/u_queue.c
@@ -147,21 +147,6 @@ util_queue_thread_func(void *input)
       u_thread_setname(name);
    }
 
-   if (queue->flags & UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY) {
-#if defined(__linux__)
-      struct sched_param sched_param = {0};
-
-      /* The nice() function can only set a maximum of 19.
-       * SCHED_IDLE is the same as nice = 20.
-       *
-       * Note that Linux only allows decreasing the priority. The original
-       * priority can't be restored.
-       */
-      pthread_setschedparam(queue->threads[thread_index], SCHED_IDLE,
-                            &sched_param);
-#endif
-   }
-
    while (1) {
       struct util_queue_job job;
 
@@ -220,7 +205,6 @@ util_queue_init(struct util_queue *queue,
    memset(queue, 0, sizeof(*queue));
    queue->name = name;
    queue->num_threads = num_threads;
-   queue->flags = flags;
    queue->max_jobs = max_jobs;
 
    queue->jobs = (struct util_queue_job*)
@@ -259,6 +243,20 @@ util_queue_init(struct util_queue *queue,
             break;
          }
       }
+
+      if (flags & UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY) {
+   #if defined(__linux__)
+         struct sched_param sched_param = {0};
+
+         /* The nice() function can only set a maximum of 19.
+          * SCHED_IDLE is the same as nice = 20.
+          *
+          * Note that Linux only allows decreasing the priority. The original
+          * priority can't be restored.
+          */
+         pthread_setschedparam(queue->threads[i], SCHED_IDLE, &sched_param);
+   #endif
+      }
    }
 
    add_to_atexit_list(queue);
diff --git a/src/util/u_queue.h b/src/util/u_queue.h
index 916802c96d..8ec959814b 100644
--- a/src/util/u_queue.h
+++ b/src/util/u_queue.h
@@ -71,7 +71,6 @@ struct util_queue {
    thrd_t *threads;
    int num_queued;
    unsigned num_threads;
-   unsigned flags;
    int kill_threads;
    int max_jobs;
    int write_idx, read_idx; /* ring buffer pointers */