FreeRTOS & H755ZI: many pxPortInitialiseStack() at port.c in call stack

[Cheolhyeon Cho]

I am testing STM32H755 MPU using the nucleo-144 (STM32H755ZI).

I used the STM32CubeMX tool to automatically generate a basic FreeRTOS example and added an ledTask to toggle an LED.

 

void ledTaskProc(void *argument)
{
  /* USER CODE BEGIN ledTaskProc */
  /* Infinite loop */
  for(;;)
  {

    if (BspButtonState == BUTTON_PRESSED)
    {
      /* Update button state */
      BspButtonState = BUTTON_RELEASED;
      /* -- Sample board code to toggle leds ---- */
		if ( 0 == led_select )
		  BSP_LED_Toggle(LED_GREEN);
		else if ( 1 == led_select )
		  BSP_LED_Toggle(LED_YELLOW);
		else
		  BSP_LED_Toggle(LED_RED);

		led_select++;
		if ( led_select >= LED_NUM )
		  led_select = 0;

      /* ..... Perform your action ..... */
    }
    else
    	osDelay(10);

  }
  /* USER CODE END ledTaskProc */
}

The operation proceeds without any issues.

However, as shown in the image, if I set a breakpoint, I see many nested pxPortInitialiseStack() calls in the call stack.

What kind of error could this be? This is not typically seen; is it possible to remove them?

 

[Saket_Om]

Hello ​@Cheolhyeon Cho 

What you see is usually **not a real error**, but probably a **debugger call-stack unwinding artifact**.  
In FreeRTOS, `pxPortInitialiseStack()` is used to build the initial stack frame of each task, and when you stop on a breakpoint the debugger may incorrectly reconstruct the task stack and show many repeated `pxPortInitialiseStack()` entries.

If the application runs correctly and you do not see faults or stack overflow, this can generally be ignored. 

[Cheolhyeon Cho]

Hi, Saket.

Thanks for your quick reply.

 

I understand.

I haven't seen this before.

 

Is there any way to prevent this unnecessary pxPortInitialiseStack() from being displayed anymore?

 

I added the following items to FreeRTOSConfig.h.

/* USER CODE BEGIN Defines */
/* Section where parameter definitions can be added (for instance, to override default ones in FreeRTOS.h) */
#define	configTASK_RETURN_ADDRESS			NULL
/* USER CODE END Defines */

* https://community.st.com/stm32cubeide-mcus-28/freertos-backtrace-problem-159746 

 

Is this a complete solution?

 

Cheolhyeon