reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git/commit/?id=6bd8375a897e4aee7a5cb7a9583f3d365fe9c3de
        git remote add arm-integrator https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git
        git fetch --no-tags arm-integrator nested_lazy_mmu
        git checkout 6bd8375a897e4aee7a5cb7a9583f3d365fe9c3de
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash mm/