访问内存越界

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#define ONEK 1024
int main()
{
    char *some_memory;
    char *mem;
    some_memory=(char *)malloc(ONEK);
    if(some_memory==NULL) exit(EXIT_FAILURE);
    mem=some_memory;
    while(1)
    {
        *mem='a';
        mem++;
    }
    exit(EXIT_SUCCESS);
}