Well, as I said apitrace didn't yield any error messages.  I'm using mesa git
from a few days ago.  I've used probably 5 versions of mesa git with similar
results.  The 4.1COMPAT is required to work around the devs shoddy coding
resulting in a black screen (I think it's due to using EXT_dsa instead of ARB
as another bug report stated).  Other people have been using Mesa apparently
without crashing but with old Ubuntu and the 4.1COMPAT.  I don't know how to
provide a backtrace with debugging symbols, I'm still a little new to this.