The SystemTap project aims to produce a Linux tool that lets application developers and system administrators take a deeper look into a running kernel. We aim to exploit the capability of a fully open-source Linux target to go beyond performance measurements, and perhaps even serve as a programmable debugger. More information on SystemTap is available from http://sources.redhat.com/systemtap/. The project wiki is at http://sources.redhat.com/systemtap/wiki/, and includes a variety of samples, presentations, and documentation.
There's a guide on how set systemtap on Fedora here