reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/gmonaco/linux.git/commit/?id=b0f3d844e192c90aac9dc773e82b8ee2b00e431b
        git remote add glemco https://git.kernel.org/pub/scm/linux/kernel/git/gmonaco/linux.git
        git fetch --no-tags glemco staging_rv_hybrid_automata
        git checkout b0f3d844e192c90aac9dc773e82b8ee2b00e431b

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash kernel/trace/