reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64le-linux-gnu
        # https://github.com/riteshharjani/linux/commit/72786c184ded2eb5805eb7fa17497ff9e85d6833
        git remote add riteshharjani https://github.com/riteshharjani/linux
        git fetch --no-tags riteshharjani kfence-fix-wip6
        git checkout 72786c184ded2eb5805eb7fa17497ff9e85d6833
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash mm/kfence/