Used 25% of memory, but the program restarts due to insufficient memory

[Yury Morgunov]

At the very beginning of the program in the main function, my stack pointer is 0x20026390, although I expected it to be in the 0x20040000 area.

In this case, static memory is used 26% - 35072 bytes.
Those. my static memory should be in the memory area 0x20020000 - 0x20028900, it turns out that I have already crossed the memory boundary by the stack pointer

The question arises, what could this be related to? I did not change the memory configuration in any way, i.e. sram0_ns is used with a size of 128 KB

Kind regards,

Yuri

[Yury Morgunov]

Using the example \ ncs \ nrf \ samples \ nrf9160 \ at_client.
I wrote a code that will break if there is enough memory for buffers.

/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
 */

#include <zephyr.h>
#include <stdio.h>
#include <drivers/uart.h>
#include <string.h>

void test_function();

static uint8_t trash[8000];

/**@brief Recoverable BSD library error. */
void bsd_recoverable_error_handler(uint32_t err)
{
	printk("bsdlib recoverable error: %u\n", err);
}

void test_function()
{
	uint8_t tras2h[40000];
	for (int i = 0; i < sizeof(tras2h); ++i) {
		tras2h[i] = i;
		if (i == sizeof(tras2h) - 1)
		{
			__BKPT(0);  // After stopping at this point, you can see that the data in trash [8000] has corrupted
		}
	}
}

void main(void)
{
	printk("The AT host sample started %d\n", *trash);
	test_function();
}

It turns out that there is no error anywhere, and the problem is that the stack pointer does not point to the end of memory. Unfortunately, I haven't found any settings to fix this.

Then, as a solution, you will have to use more static variables in the code instead of variables in the stack