Developers behind oclHashcat, an open-source password recovery / cracking utility that uses OpenCL and CUDA for being "the world's fastest password cracker", pointed out in a tweet this morning that there's a rather stomach-turning symbol within the AMD Linux OpenCL library.
Spotted was a osTestBackdoorATI string within the libamdocl64.so AMD OpenCL 64-bit library on Linux. The "osTestBackdoorATI" can be easily revealed by running strings on the compiled library, but it's not yet known what exactly AMD is doing with this "test backdoor."
This was pointed out in our forums and as of publishing I have yet to hear back from AMD with any explanation over this "test backdoor" in their binary Linux driver.
UPDATE: According to AMD's Graham Sellers on Twitter, the hook is used for obtaining memory usage statistics during testing.
UPDATE 2: AMD's official statement on this symbol.