tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   15ac8fdb74403772780be1a8c4f7c1eff1040fc4
commit: 048939088220278b8ee5bbf3769fd2f803ca9e3e [10573/11438] vrf: add mac header for tunneled packets when sniffer is attached
config: arm-randconfig-r033-20201208 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project a2f922140f5380571fb74179f2bf622b3b925697)
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 arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=048939088220278b8ee5bbf3769fd2f803ca9e3e
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 048939088220278b8ee5bbf3769fd2f803ca9e3e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm 

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 >>):

>> drivers/net/vrf.c:1447:9: error: implicit declaration of function 'vrf_add_mac_header_if_unset' [-Werror,-Wimplicit-function-declaration]
                   err = vrf_add_mac_header_if_unset(skb, vrf_dev, ETH_P_IP);
                         ^
   1 error generated.

vim +/vrf_add_mac_header_if_unset +1447 drivers/net/vrf.c

  1423	
  1424	static struct sk_buff *vrf_ip_rcv(struct net_device *vrf_dev,
  1425					  struct sk_buff *skb)
  1426	{
  1427		skb->dev = vrf_dev;
  1428		skb->skb_iif = vrf_dev->ifindex;
  1429		IPCB(skb)->flags |= IPSKB_L3SLAVE;
  1430	
  1431		if (ipv4_is_multicast(ip_hdr(skb)->daddr))
  1432			goto out;
  1433	
  1434		/* loopback traffic; do not push through packet taps again.
  1435		 * Reset pkt_type for upper layers to process skb
  1436		 */
  1437		if (skb->pkt_type == PACKET_LOOPBACK) {
  1438			skb->pkt_type = PACKET_HOST;
  1439			goto out;
  1440		}
  1441	
  1442		vrf_rx_stats(vrf_dev, skb->len);
  1443	
  1444		if (!list_empty(&vrf_dev->ptype_all)) {
  1445			int err;
  1446	
> 1447			err = vrf_add_mac_header_if_unset(skb, vrf_dev, ETH_P_IP);
  1448			if (likely(!err)) {
  1449				skb_push(skb, skb->mac_len);
  1450				dev_queue_xmit_nit(skb, vrf_dev);
  1451				skb_pull(skb, skb->mac_len);
  1452			}
  1453		}
  1454	
  1455		skb = vrf_rcv_nfhook(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, vrf_dev);
  1456	out:
  1457		return skb;
  1458	}
  1459	

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