I'm also experiencing this bug with a Radeon 6850 and GNOME 3 desktop, on
following systems:

Ubuntu 14.04 with 3.19 kernel and fglrx drivers.
openSUSE Leap 42.1 with open source drivers.

It happens when I resume from suspend. System hangs and switching to tty1
displays all the errors such as "ring 0 test failed", etc. From there, I have
to shutdown the system if I want to use it.