reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1-dirty
        # https://github.com/amir73il/linux/commit/2ccb035f66111d6c6208ff895cdb945d5776e920
        git remote add amir73il https://github.com/amir73il/linux
        git fetch --no-tags amir73il fsnotify-perf
        git checkout 2ccb035f66111d6c6208ff895cdb945d5776e920
        # 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 fs/