Fedora xen - May 2007 - 2.6.20-2925.9.fc7xen - No sound, crashing audio app.

Booted to this (64-bit) kernel under rawhide (well, f7), and noticed
under my i386 firefox with flash 9 that flash plugins would just stop
after a few seconds.  So I tested Rythmbox and it hung and needed a
force quit the first time I tried to play an MP3.

No errors in messages.  Everything find under non-xen kernel
(2.6.21-1.3194.fc7).

Any ideas or should I file a bug?   I''m somewhat reluctant to file a
bug
now given the appalling lack of information I have yet.