🚀 go-pugleaf

In general, malloc() fails when you used free() on the wrong address
(e.g. an address not returned by a previous malloc) or when a buffer
returned by another call to malloc() overflowed.  I do not know enough
about gcc to go into detail but normally malloc() and free() use
linked lists to maintain a free and a used list. This information is
kept  in the same memory regions.
Use a tool like boundschecker, or purify (I am not aware of freeware
tools) or overload malloc() and free() to do some bookkeeping.