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fix(freertos): Fix vTaskRemoveFromUnorderedEventList()

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This commit fixes and optimizes vTaskRemoveFromUnorderedEventList() in the
following ways:

- Fixed bug in single core builds where the unblocked task would be placed on
xPendingReadyList.
    - If an ISR occurs while accessing xPendingReadyList, and the ISR also
      accesses the xPendingReadyList, xPendingReadyList would be corrupted.
    - In single core builds, this function is only called from event groups with
      the scheduler suspended. Thus the function should have exclusive access to
      pxReadyTasksLists instead of xPendingReadyList.
    - The function's single core logic has now been updated to match upstream
      behavior, by always placing the unblocked task on pxReadyTasksLists.

- Optimized the function for single core builds by removing the
taskCAN_BE_SCHEDULED() check.
    - In single core builds, given that the function is always called with the
      scheduler suspended
    - Thus, the taskCAN_BE_SCHEDULED (and the subsequent routine to place the
      unblocked task on the xPendingReadyList) is not necessary for single core
      builds.
    - The function now matches upstream behavior in single core builds.

Closes https://github.com/espressif/esp-idf/issues/11883
This commit is contained in:
Darian Leung
2023-08-02 12:13:24 +02:00
parent fdcab76128
commit 5947314431
1 changed files with 54 additions and 47 deletions
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101
components/freertos/FreeRTOS-Kernel/tasks.c
View File

@@ -4077,57 +4077,64 @@ void vTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem,
configASSERT( pxUnblockedTCB );
( void ) uxListRemove( pxEventListItem );
/* Add the task to the ready list if a core with compatible affinity
* has NOT suspended its scheduler. This occurs when:
* - The task is pinned, and the pinned core's scheduler is running
* - The task is unpinned, and at least one of the core's scheduler is running */
if( taskCAN_BE_SCHEDULED( pxUnblockedTCB ) )
#if ( configUSE_TICKLESS_IDLE != 0 )
{
/* If a task is blocked on a kernel object then xNextTaskUnblockTime
* might be set to the blocked task's time out time. If the task is
* unblocked for a reason other than a timeout xNextTaskUnblockTime is
* normally left unchanged, because it is automatically reset to a new
* value when the tick count equals xNextTaskUnblockTime. However if
* tickless idling is used it might be more important to enter sleep mode
* at the earliest possible time - so reset xNextTaskUnblockTime here to
* ensure it is updated at the earliest possible time. */
prvResetNextTaskUnblockTime();
}
#endif
#if ( configNUM_CORES > 1 )
/* Add the task to the ready list if a core with compatible affinity
* has NOT suspended its scheduler. This occurs when:
* - The task is pinned, and the pinned core's scheduler is running
* - The task is unpinned, and at least one of the core's scheduler is
* running */
if( !taskCAN_BE_SCHEDULED( pxUnblockedTCB ) )
{
/* We arrive here due to one of the following possibilities:
* - The task is pinned to core X and core X has suspended its scheduler
* - The task is unpinned and both cores have suspend their schedulers
* Therefore, we add the task to one of the pending lists:
* - If the task is pinned to core X, add it to core X's pending list
* - If the task is unpinned, add it to the current core's pending list */
BaseType_t xPendingListCore = ( ( pxUnblockedTCB->xCoreID == tskNO_AFFINITY ) ? xCurCoreID : pxUnblockedTCB->xCoreID );
configASSERT( uxSchedulerSuspended[ xPendingListCore ] != ( UBaseType_t ) 0U );
/* The delayed and ready lists cannot be accessed, so hold this task
* pending until the scheduler is resumed. */
vListInsertEnd( &( xPendingReadyList[ xPendingListCore ] ), &( pxUnblockedTCB->xEventListItem ) );
}
else
#else /* configNUM_CORES > 1 */
/* In single core, the caller of this function has already suspended the
* scheduler, which means we have exclusive access to the ready list.
* We add the unblocked task to the ready list directly. */
#endif /* configNUM_CORES > 1 */
{
/* Remove the task from the delayed list and add it to the ready list. The
* scheduler is suspended so interrupts will not be accessing the ready
* lists. */
( void ) uxListRemove( &( pxUnblockedTCB->xStateListItem ) );
prvAddTaskToReadyList( pxUnblockedTCB );
#if ( configUSE_TICKLESS_IDLE != 0 )
{
/* If a task is blocked on a kernel object then xNextTaskUnblockTime
* might be set to the blocked task's time out time. If the task is
* unblocked for a reason other than a timeout xNextTaskUnblockTime is
* normally left unchanged, because it is automatically reset to a new
* value when the tick count equals xNextTaskUnblockTime. However if
* tickless idling is used it might be more important to enter sleep mode
* at the earliest possible time - so reset xNextTaskUnblockTime here to
* ensure it is updated at the earliest possible time. */
prvResetNextTaskUnblockTime();
}
#endif
}
else
{
/* We arrive here due to one of the following possibilities:
* - The task is pinned to core X and core X has suspended its scheduler
* - The task is unpinned and both cores have suspend their schedulers
* Therefore, we add the task to one of the pending lists:
* - If the task is pinned to core X, add it to core X's pending list
* - If the task is unpinned, add it to the current core's pending list */
BaseType_t xPendingListCore;
#if ( configNUM_CORES > 1 )
xPendingListCore = ( ( pxUnblockedTCB->xCoreID == tskNO_AFFINITY ) ? xCurCoreID : pxUnblockedTCB->xCoreID );
#else
xPendingListCore = 0;
#endif /* configNUM_CORES > 1 */
configASSERT( uxSchedulerSuspended[ xPendingListCore ] != ( UBaseType_t ) 0U );
/* The delayed and ready lists cannot be accessed, so hold this task
* pending until the scheduler is resumed. */
vListInsertEnd( &( xPendingReadyList[ xPendingListCore ] ), &( pxUnblockedTCB->xEventListItem ) );
}
if( prvCheckForYield( pxUnblockedTCB, xCurCoreID, pdFALSE ) )
{
/* The unblocked task has a priority above that of the calling task, so
* a context switch is required. This function is called with the
* scheduler suspended so xYieldPending is set so the context switch
* occurs immediately that the scheduler is resumed (unsuspended). */
xYieldPending[ xCurCoreID ] = pdTRUE;
if( prvCheckForYield( pxUnblockedTCB, xCurCoreID, pdFALSE ) )
{
/* The unblocked task has a priority above that of the calling task, so
* a context switch is required. This function is called with the
* scheduler suspended so xYieldPending is set so the context switch
* occurs immediately that the scheduler is resumed (unsuspended). */
xYieldPending = pdTRUE;
}
}
}
/*-----------------------------------------------------------*/