What segment? You don't have mapped memory to overrun in the kernel, so that array would have to be in a very special spot to cause a bus error in such a situation. Also, even in user space, overrunning an array is far from guaranteed in trying to address an unmapped page...in fact, it often doesn't, since mapping memory with gaps for each array is prohibitively expensive (though, debugging aides like Electric Fence rely on exactly this mechanism)