reproduce (this is a W=1 build):
        git remote add netfilter-nf https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git
        git fetch netfilter-nf main
        git checkout netfilter-nf/main
        b4 shazam https://lore.kernel.org/r/20250519103203.17255-1-djduanjiong@gmail.com
        # 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 net/netfilter/ipvs/