reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://github.com/intel-lab-lkp/linux/commit/31a4503b4c75ad0672fdeeeb12f657a9e59530cf
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Christophe-Leroy/netfilter-nft_payload-Use-csum_replace4-instead-of-opencoding/20250812-183440
        git checkout 31a4503b4c75ad0672fdeeeb12f657a9e59530cf
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 SHELL=/bin/bash net/netfilter/