>I just picked up the latest xen-2.0.bk bits, built and installed them on
>a machine that's been running an older version of xen and linux for a
>while. Now nothing works. Never mind xen, linux barely works. Every
>other command core dumps. This must be something simple... probably
>related to changing from 2.4 to 2.6 kernel?? 
What filesystem (distro) are you using? There are some issues with 
TLS in more recent versions of FC (e.g FC3 test series) -- try booting
with 'nosegfixup' or move /lib/tls/ out of the way. 
Can you pin down a particular point where this behaviour starts to 
be exhibited (i.e. play with bk cset -x and rollback csets)? 
Any serial debug output you can give us? 
cheers,
S.