reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?id=b724f305ba75b638be402fd2f130108ee1c68d5b
        git remote add paulmck-rcu https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
        git fetch --no-tags paulmck-rcu dev.2024.04.03a
        git checkout b724f305ba75b638be402fd2f130108ee1c68d5b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash