reproduce (this is a W=1 build):
        git checkout 5cb1659f412041e4780f2e8ee49b2e03728a2ba6
        b4 shazam https://lore.kernel.org/r/20241113-guestmem-library-v3-2-71fdee85676b@quicinc.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash mm/