clBLAS aborts with OpenCL Error -11 in makeGemmKernel

[Marco van Zwetselaar]

Executing any of the clblas.gemm functions in libclBLAS.so.2.12.0 (libclblas2 2.12-1build1 on bionic) aborts the calling program with this error message:

OpenCL error -11 [...] clblas-2.12/src/library/blas/xgemm.cc:244: void makeGemmKernel(_cl_kernel**, cl_command_queue, const char*, const char*, const unsigned char**, size_t*, const char*): Assertion `false' failed.

The error occurs when the backend is an OpenCL 1.1 device. This includes all GPUs supported by libclc through mesa-opencl-icd (Clover), that is effectively all AMD GPUs.

The error can be easily reproduced by running the example from the upstream README.md[1] on a machine with an AMD GPU, with environment entry OCL_ICD_VENDORS=mesa.icd.

This bug also affects all BLAS functionality in libarrayfire-opencl3, as can be seen by running e.g. examples/benchmarks/blas or any of the lin_algebra examples from the libarrayfire-doc package.

The good news is, there is a fix :-) I have submitted this PR[2] upstream, and am attaching a dquilt-ready patch as upstream releases (and even pulls to master) are very infrequent.

[1] https://github.com/clMathLibraries/clBLAS#example
[2] https://github.com/clMathLibraries/clBLAS/pull/342

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Patch removes the -cl-std kernel build option" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]