For each process a stack data structure that includes two stacks, which are joined at their bases, is created. The two stacks include a normal stack, which grows downward, and an inverse stack, which grows upward. Items on the stack data structure are segregated into protected and unprotected classes. Protected items include frame pointers and return addresses, which are stored on the normal stack. Unprotected items are function parameters and local variables. The unprotected items are stored on the inverse stack.