reproduce (this is a W=1 build):
        git checkout 2bb7005696e2246baa88772341ca032ff09a63cb
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/ drivers/ kernel/ mm/ net/