reproduce (this is a W=1 build):
        git checkout 6b36119b94d0b2bb8cea9d512017efafd461d6ac
        b4 shazam https://lore.kernel.org/r/20251013-b4-l1tf-percpu-v1-1-d65c5366ea1a@google.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 arch/x86/