System.map -- why you need to keep it insync

[Aaron Turner <aturner linuxkb org>]

I'm no expert, but I can tell you one result of a missmatch of kernel and
System.map does.  Try running 'lsof' (list open files) with a missmatch.
Oops, it doesn't always run.  'lsof' is useful when you delete that 1GB
file only to realize that your disk doesn't have 1GB more available.  
Reason?  That file was open when you deleted it, and the space won't be
made availble until that process dies.  'lsof' tells you what process it
the culprit.

This is one of many things that don't work when your System.map and kernel
don't match.  Most of them, Average Joe User won't notice, but sooner or
later it'll bite you in the butt.

-Aaron