reproduce (this is a W=1 build):
        # https://github.com/scosu/linux-sched/commit/3a93cebfaed1cf821c02f08e7be6572f55b6756a
        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 3a93cebfaed1cf821c02f08e7be6572f55b6756a

        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # clang-23 might not be officially released. Try a lower version if installation fails.
        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=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash