Hi Pablo,

I love your patch! Yet something to improve:

[auto build test ERROR on nf/master]

url:    https://github.com/0day-ci/linux/commits/Pablo-Neira-Ayuso/netfilter-nft_exthdr-check-for-IPv6-packet-before-further-processing/20210616-144640
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git master
config: x86_64-randconfig-a013-20210615 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 64720f57bea6a6bf033feef4a5751ab9c0c3b401)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/3e2206f7e73972c0cb8a3b6b8a8e0b636a959c96
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Pablo-Neira-Ayuso/netfilter-nft_exthdr-check-for-IPv6-packet-before-further-processing/20210616-144640
        git checkout 3e2206f7e73972c0cb8a3b6b8a8e0b636a959c96
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> net/netfilter/nft_exthdr.c:45:6: error: use of undeclared identifier 'skb'
           if (skb->protocol != htons(ETH_P_IPV6))
               ^
   1 error generated.


vim +/skb +45 net/netfilter/nft_exthdr.c

    35	
    36	static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
    37					 struct nft_regs *regs,
    38					 const struct nft_pktinfo *pkt)
    39	{
    40		struct nft_exthdr *priv = nft_expr_priv(expr);
    41		u32 *dest = &regs->data[priv->dreg];
    42		unsigned int offset = 0;
    43		int err;
    44	
  > 45		if (skb->protocol != htons(ETH_P_IPV6))
    46			goto err;
    47	
    48		err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
    49		if (priv->flags & NFT_EXTHDR_F_PRESENT) {
    50			nft_reg_store8(dest, err >= 0);
    51			return;
    52		} else if (err < 0) {
    53			goto err;
    54		}
    55		offset += priv->offset;
    56	
    57		dest[priv->len / NFT_REG32_SIZE] = 0;
    58		if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
    59			goto err;
    60		return;
    61	err:
    62		regs->verdict.code = NFT_BREAK;
    63	}
    64	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org