#27 Yield for micros could get stuck when a running task got in front of other tasks in the run Q

Author: dave

src/TaskManagerIO.cpp

@@ -207,14 +207,9 @@ void TaskManager::runLoop() {
 	// go through the timer (scheduled) tasks in priority order. they are stored
 	// in a linked list ordered by first to be scheduled. So we only go through
 	// these until the first one that isn't ready.
-	TimerTask* tm;
-	while((tm = tm_internal::atomicReadPtr(&first)) != nullptr) {
-#if defined(ESP8266) || defined(ESP32)
-	    // here we are making extra sure we are good citizens on ESP boards
-	    yield();
-#endif
+	TimerTask* tm = tm_internal::atomicReadPtr(&first);
 
-        if (!tm->isReady()) break;
+    while (tm && tm->isReady()) {
 
         // by here we know that the task is in use. If it's in use nothing will touch it until it's marked as
         // available. We can do this part without a lock, knowing that we are the only thing that will touch
@@ -223,14 +218,22 @@ void TaskManager::runLoop() {
         tm->execute();
         tm_internal::atomicWritePtr(&runningTask, nullptr);
         removeFromQueue(tm);
-        if(tm->isRepeating()) {
+        if (tm->isRepeating()) {
             putItemIntoQueue(tm);
-        }
-        else {
+        } else {
             tm->clear();
             tm_internal::tmNotification(tm_internal::TM_INFO_TASK_FREE, TASKMGR_INVALIDID);
         }
-	}
+        if(microsToNextTask() > 0) break;
+        tm = tm->getNext();
+
+#if defined(ESP8266) || defined(ESP32)
+        if(tm) {
+            // here we are making extra sure we are good citizens on ESP boards
+	        yield();
+	    }
+#endif
+    }
 }
 
 void TaskManager::putItemIntoQueue(TimerTask* tm) {

tests/taskMgrTests/reentrantLockingTests.cpp

@@ -0,0 +1,47 @@
+
+#include <AUnit.h>
+#include <ReentrantYieldingLock.h>
+#include "TaskManagerIO.h"
+#include "test_utils.h"
+
+using namespace aunit;
+
+ReentrantYieldingLock testLock;
+taskid_t runTaskId1;
+taskid_t runTaskId2;
+
+bool task1RunningPtrCheck = false;
+bool task2RunningPtrCheck = false;
+
+test(testGettingRunningTaskAlwaysCorrect) {
+    taskManager.reset();
+    assertEqual(nullptr, taskManager.getRunningTask());
+
+    serdebugF("Starting running task check");
+
+    runTaskId1 = taskManager.scheduleFixedRate(1, [] {
+        task1RunningPtrCheck = taskManager.getRunningTask() == taskManager.getTask(runTaskId1);
+        if(task1RunningPtrCheck) {
+            taskManager.yieldForMicros(millisToMicros(1));
+
+            task1RunningPtrCheck = taskManager.getRunningTask() == taskManager.getTask(runTaskId1);
+        }
+    });
+
+    runTaskId2 = taskManager.scheduleFixedRate(50, [] {
+        task2RunningPtrCheck = taskManager.getRunningTask() == taskManager.getTask(runTaskId2);
+    }, TIME_MICROS);
+
+    serdebugF("Scheduled running task check");
+
+    taskManager.yieldForMicros(millisToMicros(100));
+
+    serdebugF("Finished running task check, asserting.");
+
+    assertTrue(task1RunningPtrCheck);
+    assertTrue(task2RunningPtrCheck);
+}
+
+test(testReentrantLock) {
+
+}