Re: [PATCH net-next 09/10] ipv6: adopt skb_dst_dev() and skb_dst_dev_net[_rcu]() helpers

[kernel test robot <lkp@intel.com>]

Hi Eric,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/net-dst-annotate-data-races-around-dst-obsolete/20250627-192850
base:   net-next/main
patch link:    https://lore.kernel.org/r/20250627112526.3615031-10-edumazet%40google.com
patch subject: [PATCH net-next 09/10] ipv6: adopt skb_dst_dev() and skb_dst_dev_net[_rcu]() helpers
config: x86_64-buildonly-randconfig-006-20250628 (https://download.01.org/0day-ci/archive/20250628/202506281042.86fCDDNl-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250628/202506281042.86fCDDNl-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506281042.86fCDDNl-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/ipv6/exthdrs.c: In function 'ipv6_rthdr_rcv':
>> net/ipv6/exthdrs.c:786:41: error: too many arguments to function 'dev_net'
     786 |                 if (!ipv6_chk_home_addr(dev_net(skb_dst_dev(skb), addr)) {
         |                                         ^~~~~~~
   In file included from net/ipv6/exthdrs.c:25:
   include/linux/netdevice.h:2711:13: note: declared here
    2711 | struct net *dev_net(const struct net_device *dev)
         |             ^~~~~~~
>> net/ipv6/exthdrs.c:786:22: error: too few arguments to function 'ipv6_chk_home_addr'
     786 |                 if (!ipv6_chk_home_addr(dev_net(skb_dst_dev(skb), addr)) {
         |                      ^~~~~~~~~~~~~~~~~~
   In file included from include/net/ip6_route.h:5,
                    from net/ipv6/exthdrs.c:40:
   include/net/addrconf.h:122:5: note: declared here
     122 | int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr);
         |     ^~~~~~~~~~~~~~~~~~
>> net/ipv6/exthdrs.c:786:73: error: expected ')' before '{' token
     786 |                 if (!ipv6_chk_home_addr(dev_net(skb_dst_dev(skb), addr)) {
         |                    ~                                                    ^~
         |                                                                         )
>> net/ipv6/exthdrs.c:795:9: error: expected expression before '}' token
     795 |         }
         |         ^


vim +/dev_net +786 net/ipv6/exthdrs.c

   642	
   643	/********************************
   644	  Routing header.
   645	 ********************************/
   646	
   647	/* called with rcu_read_lock() */
   648	static int ipv6_rthdr_rcv(struct sk_buff *skb)
   649	{
   650		struct inet6_dev *idev = __in6_dev_get(skb->dev);
   651		struct inet6_skb_parm *opt = IP6CB(skb);
   652		struct in6_addr *addr = NULL;
   653		int n, i;
   654		struct ipv6_rt_hdr *hdr;
   655		struct rt0_hdr *rthdr;
   656		struct net *net = dev_net(skb->dev);
   657		int accept_source_route;
   658	
   659		accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
   660	
   661		if (idev)
   662			accept_source_route = min(accept_source_route,
   663						  READ_ONCE(idev->cnf.accept_source_route));
   664	
   665		if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
   666		    !pskb_may_pull(skb, (skb_transport_offset(skb) +
   667					 ((skb_transport_header(skb)[1] + 1) << 3)))) {
   668			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
   669			kfree_skb(skb);
   670			return -1;
   671		}
   672	
   673		hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
   674	
   675		if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
   676		    skb->pkt_type != PACKET_HOST) {
   677			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
   678			kfree_skb(skb);
   679			return -1;
   680		}
   681	
   682		switch (hdr->type) {
   683		case IPV6_SRCRT_TYPE_4:
   684			/* segment routing */
   685			return ipv6_srh_rcv(skb);
   686		case IPV6_SRCRT_TYPE_3:
   687			/* rpl segment routing */
   688			return ipv6_rpl_srh_rcv(skb);
   689		default:
   690			break;
   691		}
   692	
   693	looped_back:
   694		if (hdr->segments_left == 0) {
   695			switch (hdr->type) {
   696	#if IS_ENABLED(CONFIG_IPV6_MIP6)
   697			case IPV6_SRCRT_TYPE_2:
   698				/* Silently discard type 2 header unless it was
   699				 * processed by own
   700				 */
   701				if (!addr) {
   702					__IP6_INC_STATS(net, idev,
   703							IPSTATS_MIB_INADDRERRORS);
   704					kfree_skb(skb);
   705					return -1;
   706				}
   707				break;
   708	#endif
   709			default:
   710				break;
   711			}
   712	
   713			opt->lastopt = opt->srcrt = skb_network_header_len(skb);
   714			skb->transport_header += (hdr->hdrlen + 1) << 3;
   715			opt->dst0 = opt->dst1;
   716			opt->dst1 = 0;
   717			opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
   718			return 1;
   719		}
   720	
   721		switch (hdr->type) {
   722	#if IS_ENABLED(CONFIG_IPV6_MIP6)
   723		case IPV6_SRCRT_TYPE_2:
   724			if (accept_source_route < 0)
   725				goto unknown_rh;
   726			/* Silently discard invalid RTH type 2 */
   727			if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
   728				__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
   729				kfree_skb(skb);
   730				return -1;
   731			}
   732			break;
   733	#endif
   734		default:
   735			goto unknown_rh;
   736		}
   737	
   738		/*
   739		 *	This is the routing header forwarding algorithm from
   740		 *	RFC 2460, page 16.
   741		 */
   742	
   743		n = hdr->hdrlen >> 1;
   744	
   745		if (hdr->segments_left > n) {
   746			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
   747			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
   748					  ((&hdr->segments_left) -
   749					   skb_network_header(skb)));
   750			return -1;
   751		}
   752	
   753		/* We are about to mangle packet header. Be careful!
   754		   Do not damage packets queued somewhere.
   755		 */
   756		if (skb_cloned(skb)) {
   757			/* the copy is a forwarded packet */
   758			if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
   759				__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
   760						IPSTATS_MIB_OUTDISCARDS);
   761				kfree_skb(skb);
   762				return -1;
   763			}
   764			hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
   765		}
   766	
   767		if (skb->ip_summed == CHECKSUM_COMPLETE)
   768			skb->ip_summed = CHECKSUM_NONE;
   769	
   770		i = n - --hdr->segments_left;
   771	
   772		rthdr = (struct rt0_hdr *) hdr;
   773		addr = rthdr->addr;
   774		addr += i - 1;
   775	
   776		switch (hdr->type) {
   777	#if IS_ENABLED(CONFIG_IPV6_MIP6)
   778		case IPV6_SRCRT_TYPE_2:
   779			if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
   780					     (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
   781					     IPPROTO_ROUTING) < 0) {
   782				__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
   783				kfree_skb(skb);
   784				return -1;
   785			}
 > 786			if (!ipv6_chk_home_addr(dev_net(skb_dst_dev(skb), addr)) {
   787				__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
   788				kfree_skb(skb);
   789				return -1;
   790			}
   791			break;
   792	#endif
   793		default:
   794			break;
 > 795		}
   796	
   797		if (ipv6_addr_is_multicast(addr)) {
   798			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
   799			kfree_skb(skb);
   800			return -1;
   801		}
   802	
   803		swap(*addr, ipv6_hdr(skb)->daddr);
   804	
   805		ip6_route_input(skb);
   806		if (skb_dst(skb)->error) {
   807			skb_push(skb, -skb_network_offset(skb));
   808			dst_input(skb);
   809			return -1;
   810		}
   811	
   812		if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
   813			if (ipv6_hdr(skb)->hop_limit <= 1) {
   814				__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
   815				icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
   816					    0);
   817				kfree_skb(skb);
   818				return -1;
   819			}
   820			ipv6_hdr(skb)->hop_limit--;
   821			goto looped_back;
   822		}
   823	
   824		skb_push(skb, -skb_network_offset(skb));
   825		dst_input(skb);
   826		return -1;
   827	
   828	unknown_rh:
   829		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
   830		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
   831				  (&hdr->type) - skb_network_header(skb));
   832		return -1;
   833	}
   834	

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