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Remove post-timeout re-check in queue receive paths

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xQueueReceive, xQueueSemaphoreTake, and xQueuePeek re-checked the
queue state after timeout expiry and looped back if data had arrived,
while xQueueGenericSend returned errQUEUE_FULL directly on timeout.

Remove the post-timeout re-check from all three receive-side functions
to make timeout behavior symmetric with the send path. Once the
timeout has expired, return errQUEUE_EMPTY directly.

For xQueueSemaphoreTake, the mutex priority disinheritance logic is
retained and now runs unconditionally on timeout.

Refs https://github.com/FreeRTOS/FreeRTOS/issues/65
Forum: https://forums.freertos.org/t/xqueuegenericsend-and-xqueuereceive/24856
This commit is contained in:
AniruddhaKanhere 2026-04-22 17:19:46 -07:00
parent 587fe6df0d
commit 5b9a8ca934
1 changed files with 36 additions and 63 deletions
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99
queue.c
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@ -1635,22 +1635,14 @@ BaseType_t xQueueReceive( QueueHandle_t xQueue,
} }
else else
{ {
/* Timed out. If there is no data in the queue exit, otherwise loop /* The timeout has expired. */
* back and attempt to read the data. */
prvUnlockQueue( pxQueue ); prvUnlockQueue( pxQueue );
( void ) xTaskResumeAll(); ( void ) xTaskResumeAll();
if( prvIsQueueEmpty( pxQueue ) != pdFALSE ) traceQUEUE_RECEIVE_FAILED( pxQueue );
{ traceRETURN_xQueueReceive( errQUEUE_EMPTY );
traceQUEUE_RECEIVE_FAILED( pxQueue );
traceRETURN_xQueueReceive( errQUEUE_EMPTY );
return errQUEUE_EMPTY; return errQUEUE_EMPTY;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
} }
} }
} }
@ -1829,53 +1821,42 @@ BaseType_t xQueueSemaphoreTake( QueueHandle_t xQueue,
prvUnlockQueue( pxQueue ); prvUnlockQueue( pxQueue );
( void ) xTaskResumeAll(); ( void ) xTaskResumeAll();
/* If the semaphore count is 0 exit now as the timeout has #if ( configUSE_MUTEXES == 1 )
* expired. Otherwise return to attempt to take the semaphore that is
* known to be available. As semaphores are implemented by queues the
* queue being empty is equivalent to the semaphore count being 0. */
if( prvIsQueueEmpty( pxQueue ) != pdFALSE )
{ {
#if ( configUSE_MUTEXES == 1 ) /* xInheritanceOccurred could only have be set if
* pxQueue->uxQueueType == queueQUEUE_IS_MUTEX so no need to
* test the mutex type again to check it is actually a mutex. */
if( xInheritanceOccurred != pdFALSE )
{ {
/* xInheritanceOccurred could only have be set if taskENTER_CRITICAL();
* pxQueue->uxQueueType == queueQUEUE_IS_MUTEX so no need to
* test the mutex type again to check it is actually a mutex. */
if( xInheritanceOccurred != pdFALSE )
{ {
taskENTER_CRITICAL(); UBaseType_t uxHighestWaitingPriority;
{
UBaseType_t uxHighestWaitingPriority;
/* This task blocking on the mutex caused another /* This task blocking on the mutex caused another
* task to inherit this task's priority. Now this task * task to inherit this task's priority. Now this task
* has timed out the priority should be disinherited * has timed out the priority should be disinherited
* again, but only as low as the next highest priority * again, but only as low as the next highest priority
* task that is waiting for the same mutex. */ * task that is waiting for the same mutex. */
uxHighestWaitingPriority = prvGetHighestPriorityOfWaitToReceiveList( pxQueue ); uxHighestWaitingPriority = prvGetHighestPriorityOfWaitToReceiveList( pxQueue );
/* vTaskPriorityDisinheritAfterTimeout uses the uxHighestWaitingPriority /* vTaskPriorityDisinheritAfterTimeout uses the uxHighestWaitingPriority
* parameter to index pxReadyTasksLists when adding the task holding * parameter to index pxReadyTasksLists when adding the task holding
* mutex to the ready list for its new priority. Coverity thinks that * mutex to the ready list for its new priority. Coverity thinks that
* it can result in out-of-bounds access which is not true because * it can result in out-of-bounds access which is not true because
* uxHighestWaitingPriority, as returned by prvGetHighestPriorityOfWaitToReceiveList, * uxHighestWaitingPriority, as returned by prvGetHighestPriorityOfWaitToReceiveList,
* is capped at ( configMAX_PRIORITIES - 1 ). */ * is capped at ( configMAX_PRIORITIES - 1 ). */
/* coverity[overrun] */ /* coverity[overrun] */
vTaskPriorityDisinheritAfterTimeout( pxQueue->u.xSemaphore.xMutexHolder, uxHighestWaitingPriority ); vTaskPriorityDisinheritAfterTimeout( pxQueue->u.xSemaphore.xMutexHolder, uxHighestWaitingPriority );
}
taskEXIT_CRITICAL();
} }
taskEXIT_CRITICAL();
} }
#endif /* configUSE_MUTEXES */
traceQUEUE_RECEIVE_FAILED( pxQueue );
traceRETURN_xQueueSemaphoreTake( errQUEUE_EMPTY );
return errQUEUE_EMPTY;
}
else
{
mtCOVERAGE_TEST_MARKER();
} }
#endif /* configUSE_MUTEXES */
traceQUEUE_RECEIVE_FAILED( pxQueue );
traceRETURN_xQueueSemaphoreTake( errQUEUE_EMPTY );
return errQUEUE_EMPTY;
} }
} }
} }
@ -2015,22 +1996,14 @@ BaseType_t xQueuePeek( QueueHandle_t xQueue,
} }
else else
{ {
/* The timeout has expired. If there is still no data in the queue /* The timeout has expired. */
* exit, otherwise go back and try to read the data again. */
prvUnlockQueue( pxQueue ); prvUnlockQueue( pxQueue );
( void ) xTaskResumeAll(); ( void ) xTaskResumeAll();
if( prvIsQueueEmpty( pxQueue ) != pdFALSE ) traceQUEUE_PEEK_FAILED( pxQueue );
{ traceRETURN_xQueuePeek( errQUEUE_EMPTY );
traceQUEUE_PEEK_FAILED( pxQueue );
traceRETURN_xQueuePeek( errQUEUE_EMPTY );
return errQUEUE_EMPTY; return errQUEUE_EMPTY;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
} }
} }
} }