Created attachment 143612 [details]
Vertex & Fragment Shader per apitrace just before the crash

I've done some more software updates:
- Kernel 5.0.1
- Mesa 1.8.4

But the crash still happens at the very same opengl instruction. 

So the last mentioned glDrawElementsBaseVertex() call is definitely the point
of the crash but the damage that makes the gpu freeze seems to have been
created by earlier calls. I found from more testing that the previous
glUseProgram() seems to be required to trigger the crash. So I've attached the
vertex & fragment shader as shown in apitrace.