I did go back till http://cgit.freedesktop.org/mesa/mesa/commit/?id=6c99f2101fbd3edb7d5899c44ca9d984a3c0f8b6 and the bug is still there (not the crashes directly, at least I couldn't trigger them, but the error messages) so either this bug is really old or it's not a mesa bug (or, but that would be really bad: It damaged the hardware).