If you also have a known (preferably random) value as padding, and you check it at deallocation, it is called a canary, as in canaries in coal mines. It's a com

If you also have a known (preferably random) value as padding, and you check it at deallocation, it is called a canary, as in canaries in coal mines. It's a commonly used method to find/protect against overflows. For stack overflows, see -fstack-protector(-...) for gcc and clang. For heap overflows, it would depend on the implementation of malloc. glibc has mcheck() and MALLOC_CHECK_. If you're doing this as a part of release testing, ASan (and other *Sans like MSan) is worth looking into.