[Fedora-xen] 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.