hashcat -I
hashcat (v5.1.0) starting...

Cannot find an OpenCL ICD loader library.

You are probably missing the native OpenCL runtime or driver for your platform.

* AMD GPUs on Linux require this runtime and/or driver:
  "RadeonOpenCompute (ROCm)" Software Platform (1.6.180 or later)
* Intel CPUs require this runtime and/or driver:
  "OpenCL Runtime for Intel Core and Intel Xeon Processors" (16.1.1 or later)
* Intel GPUs on Linux require this runtime and/or driver:
  "OpenCL 2.0 GPU Driver Package for Linux" (2.0 or later)
* NVIDIA GPUs require this runtime and/or driver:
  "NVIDIA Driver" (367.x or later)

dpkg -l |grep -i icd
rc  beignet-opencl-icd:amd64                 1.3.2-6+b10                          amd64        OpenCL library for Intel GPUs
ii  nvidia-egl-icd:amd64                     418.56-2                             amd64        NVIDIA EGL installable client driver (ICD)
ii  nvidia-opencl-icd:amd64                  418.56-2                             amd64        NVIDIA OpenCL installable client driver (ICD)
ii  nvidia-vulkan-icd:amd64                  418.56-2                             amd64        NVIDIA Vulkan installable client driver (ICD)
ii  ocl-icd-dev:amd64                        2.2.12-2                             amd64        Development files to build a ICD Loader
ii  ocl-icd-libopencl1:amd64                 2.2.12-2                             amd64        Generic OpenCL ICD Loader
ii  ocl-icd-opencl-dev:amd64                 2.2.12-2                             amd64        OpenCL development files
rc  pocl-opencl-icd:amd64                    1.2-5                                amd64        pocl ICD