https://bugs.freedesktop.org/show_bug.cgi?id=61182
--- Comment #8 from Jürg Billeter j@bitron.ch --- I don't have a usable backtrace at hand, but I'm seeing very similar crashes in gnome-shell as well with Mesa 9.1 and Linux 3.8.3. With Mesa 9.0.3, I haven't noticed any crashes so far. It crashes much more frequently with two monitors (both 1920x1200) attached than with just one.
This is on an x86-64 system with Radeon HD 4770.