Comment by antonchekhov

Back in the early '90s, I was a big fan of the C/C++ debugging library "electric fence" (written by Bruce Perens) - it was a malloc() implementation that used mmap() to set the pages of the returned buffer such that any writes in that region (and even read accesses!) caused a segfault to happen, and the program halts, so you can examine the stack. It was a godsend.