reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/zab/linux-rpdfs.git/commit/?id=cd9dddd9348e8c1bbbdedf8547a6c42b73b03f82
        git remote add zab-rpdfs https://git.kernel.org/pub/scm/linux/kernel/git/zab/linux-rpdfs.git
        git fetch --no-tags zab-rpdfs rpdfs-initial
        git checkout cd9dddd9348e8c1bbbdedf8547a6c42b73b03f82

        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=$HOME/0day COMPILER=clang-17 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-17 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/rpdfs/