reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/alexshi/linux/commit/7e49c7e572a22b165bd9a3f2e9e1fd4085a40fb8
        git remote add alexshi https://github.com/alexshi/linux.git
        git fetch --no-tags alexshi mmunstable
        git checkout 7e49c7e572a22b165bd9a3f2e9e1fd4085a40fb8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash fs/