reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/amir73il/linux/commit/2e6c8d603136baf0de510ba069ad78a449012807
        git remote add amir73il https://github.com/amir73il/linux
        git fetch --no-tags amir73il ovl_real_file
        git checkout 2e6c8d603136baf0de510ba069ad78a449012807
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/iio/light/ fs/overlayfs/