And of course -- non-accessable memory: Guard pages Concept: Put an unmapped page between all allocations Like "Electric Fencing" In malloc() .... malloc.conf 'G' option makes page allocations be guarded In mmap() Some application breakage: This is when we find out how much "Open Source" is garbage So much software accesses 1 byte beyond the end of an object, generating a fault.. As a result, this cannot be enabled by default yet.