reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux.git/commit/?id=06ed7e7e7aa656f7054af7d3d3387a07244d85b1
        git remote add boqun https://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux.git
        git fetch --no-tags boqun rust-sync.20260105a
        git checkout 06ed7e7e7aa656f7054af7d3d3387a07244d85b1

        # install um cross compiling tool for clang build
        # apt-get install binutils-um-linux-gnu
        # clang-22 might not be officially released. Try a lower version if installation fails.
        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=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um prepare