reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git/commit/?id=0c990a8562a127b71e72eec4b9b92ba0f602510c
        git remote add rcu https://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git
        git fetch --no-tags rcu rcu/refscale
        git checkout 0c990a8562a127b71e72eec4b9b92ba0f602510c

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.3.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.3.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash kernel/rcu/