reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git/commit/?id=33656c801bc94615e8b02f01f36eff752dc5086b
        git remote add xiang-erofs https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
        git fetch --no-tags xiang-erofs dev-test
        git checkout 33656c801bc94615e8b02f01f36eff752dc5086b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/