reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?id=c7aacce2216be329acb2a6c01543caed73ac395f
        git remote add jfern https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git
        git fetch --no-tags jfern sched/dlserver.debug.mar3.2024
        git checkout c7aacce2216be329acb2a6c01543caed73ac395f
        # 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