Merge branch 'fix/priority_inv_when_remove_from_unordered_event_list_v5.3' into 'release/v5.3'

fix(freertos): Fixed priority inversion when setting event group bits (v5.3)

See merge request espressif/esp-idf!34123

Author: ESP-Marius

components/freertos/FreeRTOS-Kernel/tasks.c

@@ -4123,10 +4123,19 @@ void vTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem,
         if( taskIS_YIELD_REQUIRED( pxUnblockedTCB, pdFALSE ) == pdTRUE )
         {
             /* 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;
+             * a context switch is required. */
+            #if ( configNUM_CORES > 1 )
+
+                /* In SMP mode, this function is called from a critical section, so we
+                 * yield the current core to schedule the unblocked task. */
+                portYIELD_WITHIN_API();
+            #else /* configNUM_CORES > 1 */
+
+                /* In single-core mode, this function is called with the scheduler suspended
+                 * so xYieldPending is set so the context switch occurs immediately once the
+                 * scheduler is resumed (unsuspended). */
+                xYieldPending[ xCurCoreID ] = pdTRUE;
+            #endif /* configNUM_CORES > 1 */
         }
     }
 }

components/freertos/test_apps/freertos/kernel/event_groups/test_freertos_eventgroups.c

@@ -132,6 +132,57 @@ TEST_CASE("FreeRTOS Event Group Sync", "[freertos]")
     vEventGroupDelete(eg);
 }
 
+static TaskHandle_t run_order[2];
+static uint32_t run_order_index = 0;
+
+void task_test_eg_prio(void *arg)
+{
+    TaskHandle_t main_task_hdl = (TaskHandle_t)arg;
+
+    /* Notify the main task that this task has been created */
+    xTaskNotifyGive(main_task_hdl);
+
+    /* Wait for the event group bits to be set */
+    TEST_ASSERT_EQUAL(1, xEventGroupWaitBits(eg, 1, pdTRUE, pdTRUE, portMAX_DELAY));
+
+    /* Record the task handle in the run order array */
+    run_order[run_order_index++] = xTaskGetCurrentTaskHandle();
+
+    /* Suspend the task */
+    vTaskSuspend(NULL);
+}
+
+TEST_CASE("FreeRTOS Event Groups do not cause priority inversion when higher priority task is unblocked", "[freertos]")
+{
+    run_order[0] = NULL;
+    run_order[1] = NULL;
+    run_order_index = 0;
+
+    /* Initialize the event group */
+    eg = xEventGroupCreate();
+
+    /* Create a task with higher priority than the task that will set the event group bits */
+    TaskHandle_t higher_prio_hdl;
+    TEST_ASSERT_EQUAL(pdTRUE, xTaskCreatePinnedToCore(task_test_eg_prio, "task_test_eg_prio", 2048, (void *)xTaskGetCurrentTaskHandle(), CONFIG_UNITY_FREERTOS_PRIORITY + 1, &higher_prio_hdl, CONFIG_UNITY_FREERTOS_CPU));
+
+    /* Wait for the task to be created */
+    ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
+
+    /* Set the event group bits */
+    xEventGroupSetBits(eg, 1);
+
+    /* Record the task handle in the run order array */
+    run_order[run_order_index++] = xTaskGetCurrentTaskHandle();
+
+    /* Verify that the higher priority task was unblocked and immediately scheduled and the lower priority task was preempted */
+    TEST_ASSERT_EQUAL(higher_prio_hdl, run_order[0]);
+    TEST_ASSERT_EQUAL(xTaskGetCurrentTaskHandle(), run_order[1]);
+
+    /* Clean up */
+    vEventGroupDelete(eg);
+    vTaskDelete(higher_prio_hdl);
+}
+
 /*-----------------Test case for event group trace facilities-----------------*/
 #ifdef  CONFIG_FREERTOS_USE_TRACE_FACILITY
 /*