reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-52-g1cf3d98c-dirty
        # https://github.com/oracle/dtrace-linux-kernel/commit/105aecdb38625c8adc8b0d1c90ec56b3577c85f1
        git remote add oracle-dtrace https://github.com/oracle/dtrace-linux-kernel
        git fetch --no-tags oracle-dtrace v2/6.7
        git checkout 105aecdb38625c8adc8b0d1c90ec56b3577c85f1
        # 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