reproduce (this is a W=1 build):
        git checkout 56bc1719652e7a937bc9856f76f0c0fbf8ce1b23
        # 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 drivers/ net/