reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/smfrench/smb3-kernel/commit/7db9a00c4d9bf4996177e4946241885234afb5c0
        git remote add smfrench-smb3 https://github.com/smfrench/smb3-kernel.git
        git fetch --no-tags smfrench-smb3 for-next
        git checkout 7db9a00c4d9bf4996177e4946241885234afb5c0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash fs/smb/client/