PIC32 Application using queue crashes

Kernel
1

aethamyn wrote on Thursday, November 01, 2012:

Hi everybody,

I am facing a problem with PIC32 port when I try to use queues. I got a simple application, only one task, one queue. There are correctly initialised (task and queue handles aren’t null), vTaskStartScheduler() is called, then my task tries to receive a message from the queue with xQueueReceive().

I get stuck in vListInsert(), but :

1. My stack task doesn’t overflow (I use method 2 for stack checking and vApplicationStackOverflowHook() is never called)

2. I don’t think I have trouble with interrupts priorities : Kernell priority is 1, max interrupt priority is set to 4. Plus, I don’t have used any other interrupts than those used for the kernell.

3. When xQueueReceived() is called, the scheduler is running (xSchedulerRunning = 1 and uxSchedulerSuspended = 0) but in vListInsert(), scheduler is suspended (is that ok ?). Actually it is suspended when calling vTaskSuspendAll in xQueueGenericReceive().

4. Queue has been initialised, no pending message.

Then, a bus exception is thrown (DBE). I have the same problem if I create a second task that put a message into the queue.

If it could help, I am using XC32 v1.11. I can reproduce the problem with MPLAB Sim and when I am debugging with a Digilent Cerebot MX7ck board with built-in licensed debugger.

2

davedoors wrote on Thursday, November 01, 2012:

As your application is so small, please post the code. Make sure to enclose it with the Codify Text tags (button just above the text entry box in the forum).

3

aethamyn wrote on Friday, November 02, 2012:

- Main():

int main(void) 
{
    vSetupHardware();
   Create_Ressources_OSTracing();
    vTaskStartScheduler();
    return 0;
}

- Create_Ressources_OSTracing():

ErrorCode_t Create_Ressources_OSTracing (void)
{
	ErrorCode_t ErrorCode = {0};
	#ifdef OS_TRACE
	// 1. Create Task
	if((ErrorCode.Code&ERRCODEMASK) == CODE_000_NO_ERROR)
	{
		if(xTaskCreate(_OS_Trace_TaskHandler,
					   "RTOS Trace Task",
					   STACKSIZE_OS_TRACE,
					   NULL,
					   PRIORITY_OS_TRACE,
					   &TASK_OSTracing) != pdPASS)
		{
			ErrorCode.Code = LAYER_Service | TASKID_OSTrace | CODE_002_MEMORY_ALLOCATION_ERROR;
		}
	}
	
	// 2. Create Message to Send Queue
	if((ErrorCode.Code&ERRCODEMASK) == CODE_000_NO_ERROR)
	{
		Q_OSTracing = xQueueCreate(MAX_MSG_Q_OS_TRACE, sizeof(OS_TRACE_Msg_t));
		if(Q_OSTracing == NULL)
		{
			ErrorCode.Code = LAYER_Service | TASKID_OSTrace | CODE_002_MEMORY_ALLOCATION_ERROR;
		}
		else
		{
			#if __DEBUG
			vQueueAddToRegistry(Q_OSTracing, "OS Tracing Queue");
			#endif
		}	
	}
	#endif
	return ErrorCode;
}

- The task - _OS_Trace_TaskHandler():

void _OS_Trace_TaskHandler (void * pvTaskParam)
{
	OS_TRACE_Msg_t		TraceMsg;
	OS_TRACE_Time_t		TraceTime;
	
	vTaskDelayMs(2000);
	
	while(1)
	{
		if(xQueueReceive(&Q_OSTracing, &TraceMsg, portMAX_DELAY) == pdPASS)
		{
			if(TraceMsg.DateFlag)
			{
				_OS_Trace_GetTime(&TraceTime);
				_OS_Trace_FormatTime(&TraceTime, &TraceMsg);
			}
			
			_OS_Trace_LogTrace(&TraceMsg);
		}
	}
}

vTaskDelayMs() is a macro that calls vTaskDelay and converts parameter in ms to ticks with portTICK_RATE_MS.

4

rtel wrote on Friday, November 02, 2012:

I’m curious why you test

if((ErrorCode.Code&ERRCODEMASK) == CODE_000_NO_ERROR)

when ErrorCode is a local variable and just been initialised so can’t hold any value other than 0, but that is probably not relevant.

What is probably relevant is the following call:

if(xQueueReceive(&Q_OSTracing, &TraceMsg, portMAX_DELAY) == pdPASS)

You don’t show the definition of Q_OSTracing, but I suspect you don’t need the ‘&’ in front of it.

If you declare it as:

xQueueHandle Q_OSTracing;

…and it the queue has been created, then you can read from it using:

xQueueReceive(Q_OSTracing, &TraceMsg, portMAX_DELAY);

As you are using portMAX_DELAY, you only need to test the return value if INCLUDE_vTaskSuspend is not set to 1 in FreeRTOSConfig.h.  That is because if INCLUDE_vTaskSuspend is set to one portMAX_DELAY will act as an indefinite wait.

Regards.

5

aethamyn wrote on Friday, November 02, 2012:

when ErrorCode is a local variable and just been initialised so can’t hold any value other than 0, but that is probably not relevant.

Yes it is, actually it’s more a “way” that I try to respect, I agree this test isn’t usefull :wink:

What is probably relevant is the following call:  You don’t show the definition of Q_OSTracing, but I suspect you don’t need the ‘&’ in front of it. If you declare it as:
xQueueHandle Q_OSTracing;

Exact ! I’m more familiar with EmbOS from Segger, in which queue type is a structure, not a handle, which is actually just a void pointer … I made the same mistake when I wanted to put a message into the queue :

if(xQueueIsQueueFullFromISR(Q_OSTracing) != pdFALSE)
	{
		xQueueSend(&Q_OSTracing, &TraceMsg, MS_TO_TICK(50));
	}

That’s why I got troubles in sending messages too.

As you are using portMAX_DELAY, you only need to test the return value if INCLUDE_vTaskSuspend is not set to 1 in FreeRTOSConfig.h. That is because if INCLUDE_vTaskSuspend is set to one portMAX_DELAY will act as an indefinite wait.

Yes, my task is suspended. I will let the test because this task maybe be used with different configuration of FreeRTOS, it is some kind of generic method to trace OS and application events for a few different  FreeRTOS based softwares.

Anyway, thank you for your help !