reproduce (this is a W=1 build):
        # https://github.com/rgushchin/linux/commit/36dfd96fa3fbd7d4057fe22dfa657b62a9b6865b
        git remote add rgushchin https://github.com/rgushchin/linux.git
        git fetch --no-tags rgushchin bpfoom.3.9
        git checkout 36dfd96fa3fbd7d4057fe22dfa657b62a9b6865b
        # apt-get install sparse
        # sparse version: v0.6.4-73-gfbdde312

        # 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 mm/ sound/soc/sdca/