#include <stdio.h>
#include <string.h>
#include <sys/mman.h>

static void show_stack(void)
{
	FILE *map;
	char buf[1000];

	map = fopen("/proc/self/maps", "r");
	if (!map)
		return;

	while (fgets(buf, 1000, map)) {
		if (!strstr(buf, "[stack]"))
			continue;
		fputs(buf, stdout);
	}

	fclose(map);
}

int main(void)
{
	show_stack();
	mlockall(MCL_CURRENT | MCL_FUTURE);
	show_stack();
	return 0;
}