There are lots of crazy buggy stuff, which I still haven't refactored. But you might be particularly interested in code fragment from this file (lines 197-306), where the check for texture sharing functionality is performed:
Works as follows: OpenGL texture is created and exposed to OpenCL via clCreateFromGLTexture2D. Then it is filled through FBO with some color, acquired for OpenCL, and check is performed that OpenCL image have the same content.
P.S: We have tested sample on AMD and it crashed (fine on NVidia). Not so far ago it worked on both cards. Tomorrow I try to locate bug, but it might be a driver problem.