reproduce (this is a W=1 build):
        # https://github.com/morimoto/linux/commit/d86137d04f7f273d2e266a7248b3745ebdfa44a3
        git remote add morimoto https://github.com/morimoto/linux
        git fetch --no-tags morimoto string-helper-2025-07-18
        git checkout d86137d04f7f273d2e266a7248b3745ebdfa44a3
        # 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 arch/um/drivers/