[CentOS] qemu-kvm segfaults on starting guests

I have a Centos 5.5 on an AMD 64 system (Athlon II x2 250).

I caught up on updates today, including -- kernel 2.6.18-194.17.1.el5 -- glibc 2.5-49.el5_5.5.i686

I have several guests that were working before the update, but now none of them will boot.

With each attempt I get a message in /var/log/messages: -- kernel: qemu-kvm[xx]: segfault at 000000379fc0da11 rip 00002b9f2732283f rsp 00000000446a6e80 error 7

Has this happened to others? Any fix. I see similar bugreports, but they are not recent, and not quite like this. The closest thing I can find was on an nvidia list about vmware posted today -- so maybe this has something to do with needing to rebuild the nvidia drivers with every kernel update.

Any ideas?