free() Woes

This phenomena could lead to all sorts of problems:

double-freeing of the same chunk (which would corrupt malloc's memory tables).

accessing a freed memory before it was re-allocated, which could also corrupt malloc's memory tables, or lead us to read data from the beginning of the chunk, that was altered by the call to free().

accessing a freed memory after it was re-allocated, thus having two different parts of the program trying to use it at the same time, for different purposes.