reproduce (this is a W=1 build):
        # https://github.com/xinli-intel/linux-fred-public/commit/2724c18085f2a04c6bb7d737f1c9665b4f2b895e
        git remote add xinli-intel-fred-public https://github.com/xinli-intel/linux-fred-public.git
        git fetch --no-tags xinli-intel-fred-public fred_kvm_v6-intel_next
        git checkout 2724c18085f2a04c6bb7d737f1c9665b4f2b895e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash