core: fix wrong logic in _osmo_it_q_dequeue()
If the given queue is empty, queue->list.next points to &queue->list.
Current implementation would call llist_del() on the queue's llist_head,
decrement queue->current_length (which will be 0), and return a pointer
to &queue->list to the caller. This is completely wrong.
- Use the existing item_dequeue(), which does exactly what we need.
- Do not decrement the current_length if nothing was dequeued.
- Uncomment code in the unit test, we should not crash anymore.
Change-Id: I63094df73b166b549616c869ad908e9f4f7d46d1
Fixes: CID#336557
diff --git a/src/core/it_q.c b/src/core/it_q.c
index a3ff420..810dc90 100644
--- a/src/core/it_q.c
+++ b/src/core/it_q.c
@@ -245,7 +245,7 @@
/*! Thread-safe de-queue from an inter-thread message queue.
* \param[in] queue Inter-thread queue from which to dequeue
- * \returns dequeued message buffer; NULL if none available
+ * \returns llist_head of dequeued message; NULL if none available
*/
struct llist_head *_osmo_it_q_dequeue(struct osmo_it_q *queue)
{
@@ -254,12 +254,9 @@
pthread_mutex_lock(&queue->mutex);
- if (llist_empty(&queue->list))
- l = NULL;
- l = queue->list.next;
- OSMO_ASSERT(l);
- llist_del(l);
- queue->current_length--;
+ l = item_dequeue(&queue->list);
+ if (l != NULL)
+ queue->current_length--;
pthread_mutex_unlock(&queue->mutex);
diff --git a/tests/it_q/it_q_test.c b/tests/it_q/it_q_test.c
index 9545183..6025e39 100644
--- a/tests/it_q/it_q_test.c
+++ b/tests/it_q/it_q_test.c
@@ -81,11 +81,9 @@
q1 = osmo_it_q_alloc(OTC_GLOBAL, "q1", 12, NULL, NULL);
OSMO_ASSERT(q1);
-#if 0
printf("try dequeueing from an empty queue\n");
osmo_it_q_dequeue(q1, &item, list);
OSMO_ASSERT(item == NULL);
-#endif
printf("adding queue entries up to the limit\n");
for (unsigned int i = 0; i < qlen; i++) {
@@ -101,11 +99,9 @@
talloc_free(item);
}
-#if 0
printf("try dequeueing from an empty queue\n");
osmo_it_q_dequeue(q1, &item, list);
OSMO_ASSERT(item == NULL);
-#endif
osmo_it_q_destroy(q1);
}
diff --git a/tests/it_q/it_q_test.ok b/tests/it_q/it_q_test.ok
index 91ba0ce..e89b78d 100644
--- a/tests/it_q/it_q_test.ok
+++ b/tests/it_q/it_q_test.ok
@@ -11,8 +11,10 @@
== Entering test case tc_enqueue_dequeue
allocating q1
+try dequeueing from an empty queue
adding queue entries up to the limit
removing queue entries up to the limit
+try dequeueing from an empty queue
== Entering test case tc_eventfd
allocating q1