https://bugs.freedesktop.org/show_bug.cgi?id=98021
--- Comment #1 from Nicolai Hähnle nhaehnle@gmail.com --- Hi Stepan, it's called an override for a reason. When you enable it, you're operating outside of the supported parameters, and shouldn't be surprised when something crashes. Don't report a bug for something like that.
That said, radeonsi has supported OpenGL 4.3 for several months now. For SI-based cards like yours, you need a more recent kernel. The radeon module of older kernels lacks some of the functionality that is required for compute shaders.