reproduce (this is a W=1 build):
        # https://github.com/jimc/linux/commit/c64a3f08a0141ea44aaf52cb647a97400c5e1dd0
        git remote add jimc https://github.com/jimc/linux.git
        git fetch --no-tags jimc scratchpad-v10
        git checkout c64a3f08a0141ea44aaf52cb647a97400c5e1dd0

        # 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 kernel/locking/