Fix yet another minor race condition in the non-threadqueue queue dat…

…a structure.
sandialabs · Oct 21, 2024 · 138c8f5 · 138c8f5
1 parent 2945351
commit 138c8f5
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Showing 2 changed files with 6 additions and 5 deletions.
diff --git a/include/qt_queue.h b/include/qt_queue.h
@@ -10,7 +10,7 @@
 
 typedef struct qthread_queue_node_s {
   struct qthread_queue_node_s *_Atomic next;
-  qthread_t *thread;
+  qthread_t *_Atomic thread;
 } qthread_queue_node_t;
 
 typedef struct qthread_queue_NEMESIS_s {

diff --git a/src/queue.c b/src/queue.c
@@ -203,7 +203,7 @@ void INTERNAL qthread_queue_internal_nosync_enqueue(qthread_queue_nosync_t *q,
   assert(q);
   assert(t);
 
-  node->thread = t;
+  atomic_store_explicit(&node->thread, t, memory_order_relaxed);
   atomic_store_explicit(&node->next, NULL, memory_order_relaxed);
   if (atomic_load_explicit(&q->tail, memory_order_relaxed) == NULL) {
     atomic_store_explicit(&q->head, node, memory_order_relaxed);
@@ -229,7 +229,7 @@ qthread_queue_internal_nosync_dequeue(qthread_queue_nosync_t *q) {
       &q->head,
       atomic_load_explicit(&node->next, memory_order_relaxed),
       memory_order_relaxed);
-    t = node->thread;
+    t = atomic_load_explicit(&node->thread, memory_order_relaxed);
     FREE_TQNODE(node);
   }
   return t;
@@ -241,7 +241,7 @@ void INTERNAL qthread_queue_internal_NEMESIS_enqueue(qthread_queue_NEMESIS_t *q,
 
   node = ALLOC_TQNODE();
   assert(node != NULL);
-  node->thread = t;
+  atomic_store_explicit(&node->thread, t, memory_order_relaxed);
   atomic_store_explicit(&node->next, NULL, memory_order_relaxed);
 
   prev = qt_internal_atomic_swap_ptr((void **)&(q->tail), node);
@@ -279,7 +279,8 @@ qthread_queue_internal_NEMESIS_dequeue(qthread_queue_NEMESIS_t *q) {
         atomic_store_explicit(&dequeued->next, NULL, memory_order_relaxed);
       }
     }
-    qthread_t *retval = dequeued->thread;
+    qthread_t *retval =
+      atomic_load_explicit(&dequeued->thread, memory_order_relaxed);
     FREE_TQNODE(dequeued);
     return retval;
   } else {