reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://github.com/intel-lab-lkp/linux/commit/6b307ee261e218a623e714a7724ddf2ea9d1ecb6
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Guillaume-Nault/vxlan-Pull-inner-IP-header-in-vxlan_xmit_one/20240607-002253
        git checkout 6b307ee261e218a623e714a7724ddf2ea9d1ecb6
        # 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=i386 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/net/vxlan/