reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/tobetter/linux/commit/5c70fa7bdce06ef372ba87e68f1c1b8bb2174d76
        git remote add tobetter https://github.com/tobetter/linux
        git fetch --no-tags tobetter odroid-6.10.y
        git checkout 5c70fa7bdce06ef372ba87e68f1c1b8bb2174d76
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/char/