reproduce (this is a W=1 build):
        # https://github.com/alexshi/linux/commit/84368e4373e673f216fd9b354366ea118ae56b0f
        git remote add alexshi https://github.com/alexshi/linux.git
        git fetch --no-tags alexshi mmunstable2
        git checkout 84368e4373e673f216fd9b354366ea118ae56b0f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash mm/