When your Linux system completely crashes or hangs the last thing you can do is to take a system memory dump and afterwards inspect the dump to identify the problem. Inspecting the dump you can use lcrash - the Linux crash dump analyzer.
lcrash is part of the lkcd project which was initiated by SGI. Please refer to the Project Home Page for details regarding this project.
lcrash has a command line interface with simple command line editing, history mechanism and - in recent versions - command line completion. Even a graphical interface exists for lcrash. It is called qlcrash and resides also at sourceforge.
Some important features of lcrash are:
kernel structures are displayed in C-like fashion,
virtual to physical address translation is automatically performed,
kernel modules are supported when analyzing a dump.