reproduce (this is a W=1 build):
        git remote add rppt-memblock https://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock.git
        git fetch rppt-memblock fixes
        git checkout rppt-memblock/fixes
        b4 shazam https://lore.kernel.org/r/20251119154427.1033475-13-eugen.hristev@linaro.org

        # 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 kernel/ mm/