segmentation fault at to small stacksize( ulimit -s)

Hello, i have a script which ends up in a segmentation fault.(i think memory leak) if i increase stack size with ulimit -s the script shows correct error: Fatal error: Allowed memory size of 41943040 exhausted (tried to allocate 16 bytes) the default of stack size is 8192 kb why is there a seg.fault if stack size is on default value and not a correct error-message. What is the recommended way to avoid this? Thanks, Hajo