Comment 31 for bug 337608

Yeah, I think the corruption I saw is due to migration code (or more specifically the dirty update stuff), but the crash must be due to either an unmap happing at the wrong time or the mapping size changing like you say. If you have a driver that doesn't manage pixmaps it's pretty easy to see the corruption with the default migration scheme (always I think?) at the Java test page referenced in this bug.

I'd like to solve the problem properly as well, but I'll have to dig through the EXA code a lot more (I haven't looked at the migration or sys vs offscreen mapping code much at all).