#define _GNU_SOURCE

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/mman.h>

#define STACK_SIZE	2*4096

int main()
{
	unsigned char *end;
	/* Allocate stack */
        unsigned char *stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE,
			MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN, 0, 0);

	printf("stack = %p\n", stack);
	end = stack + STACK_SIZE - 8;
	printf("end = %p\n", end);
	printf("write to *end\n");
	*end = 0;
	printf("write to *stack\n");
	*(stack) = 0;
	printf("write to *(stack-1)\n");
	*(stack-1) = 0;
}