reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://github.com/weiny2/linux-kernel/commit/2d11892dead2fcc454ceb5779c01584d1bed0c6b
        git remote add weiny2 https://github.com/weiny2/linux-kernel.git
        git fetch --no-tags weiny2 cxl-cper-testing
        git checkout 2d11892dead2fcc454ceb5779c01584d1bed0c6b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 SHELL=/bin/bash