pvPortMalloc failes after the scheduler is started

[yuliap]

Hi,

I have trouble with the pvPortMalloc function. My project contains the FreeRTOS component from Erich Styger and lwip from KSDK. I set the momery scheme to 3 in FreeRTOS and define a large heap in the CPU component. Large enough for all the memory allocations I need. The process initialization goes as expected, the memory is allocated without errors. When the scheduler is started a thread calls netconn_new, which in the end calls pvPortMalloc. The return value is zero. If I move the netconn_new call to before the scheduler, the memory allocation returns a sensible value. It looks almost like when the scheduler is started, the malloc is not functioning any more. Does anyone have any ideas about what it could be? My HW is custom..

Regards,

Julia

[BlackNight]

Hi Julia,

my thinking is that your malloc() is not thread safe? FreeRTOS will do its usage of malloc() in a thread safe way (disabling interrupts.

What I think happens on your side is:

- lwip calls malloc() (not thread safe)

- tick interrupt happens, and the RTOS/task will call malloc() in thread safe way.

- as lwip started a malloc(), but not finished it, your malloc is screwed up.

Could you try replacing malloc() with pvPortMalloc() in lwip?

Erich

[yuliap]

Hi Erich,

thanks for the reply.

I modified the blinky task instead, and removed all the lwip usage from my project. The blinky task is now:

static void task_blinky(void *pvParameters) {

  (void)pvParameters; /* parameter not used */

  for(;;) {

      void *pvReturn = pvPortMalloc(100);

      GPIO_DRV_TogglePinOutput(DIAG_LED0);

      vTaskDelay(500/portTICK_RATE_MS);

      vPortFree(pvReturn);

  }

}

The program still crashes at the first call to pvPortMalloc in the blinky task, i.e after the task is scheduled for the first time. The pvReturn is zero. I noticed also that the SP register value drops from the top of the "data 0x2000000" partition to almost its start. I wonder if I configured the FreeRTOS wrong in a way...The FreeRTOSConfig.h is similar to the demo examples one.

[BlackNight]

Hi Julia,

I'm affraid that you will need to debug it to find out what is going wrong here.

Erich