I had segfault problem FireFox/Mozilla when I view big SVG diagram or launch tarantella native client after I upgraded to glibc 2.3.5-0
I downgraded back to previous glibc version (glibc 2.3.4-2 including nptl-devel and nscd) using --force option and it is stable now.
Please don't use --force (or --nodeps) or advise anyone else to do so - it can lead to screwed-up systems - as it's hardly ever necessary. The --oldpackage option would be a better choice in this case.
Haven't noticed any glibc problems myself since updating but that's not to say such problems aren't there.
Paul.
