reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat.git/commit/?id=c5b2f44ae0af3036dffc5f3252cd807e42ac8d2b
        git remote add linkinjeon-exfat https://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat.git
        git fetch --no-tags linkinjeon-exfat iomap-work
        git checkout c5b2f44ae0af3036dffc5f3252cd807e42ac8d2b

        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=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/gpu/drm/ fs/exfat/