Printing Stack and Heap pointers

[Jawad]

Hi everyone,

I am facing memory leak issues while using nrf52 iot SDK for MQTT. The application has a high RAM usage and I am running into memory leakage issue where program starts behaving abnormally after running for few times. Could anyone please help me in printing the stack and heap pointers so that I can figure where exactly when they go out of bounds?

Thanks

[bjorn-spockeli]

Hi Jawad,

a quick-and-dirty way of obtaining the value of the stack pointer is to push a variable to the stack and then print the address of said variable, i.e.

void print_stack_pointer() 
{
  uint32_t * ptr = NULL;
  NRF_LOG_INFO("%p \n", (uint32_t)&ptr);
}

I am not sure if you can use the same approach to get the current heap pointer , but I thought that you were'nt using the heap since this is related to this and this question.

[Jawad]

Hi Bjorn,

Thanks for the comment. I was not using heap before but now for the nrf52 implementation for mqtt I need to use the calloc and malloc functions for which I need heap. That's why I want to print heap pointer.

Thanks

[RK]

There's a CMSIS defined function __get_PSP() which should get the stack pointer for any supported compiler, it uses the MRS instruction to do it.

The heap pointer however, that depends entirely on what malloc implementation you're using.

[Jawad]

Thanks RK,

I am using nrf52 IoT SDK implementation for MQTT with following malloc

void * nrf_malloc(uint32_t size){

uint8_t * buffer = NULL;
uint32_t allocated_size = size;

uint32_t retval = nrf_mem_reserve(&buffer, &allocated_size);

if (retval != NRF_SUCCESS)
{
    buffer = NULL;
}

return buffer;

}

[bjorn-spockeli]

You could look into the __heapstats function, see this link. Just make sure that you include stdlib.h and uncheck Use MircroLib under "Options for Target".