reproduce (this is a W=1 build):
        # https://github.com/scosu/linux-sched/commit/d7248704a9e61a04dbe3289ba19e99273d16504e
        git remote add scosu-sched https://github.com/scosu/linux-sched
        git fetch --no-tags scosu-sched topic/mmap-cap-prot-wip/v6.18
        git checkout d7248704a9e61a04dbe3289ba19e99273d16504e

        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        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=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash