ipv6: annotate data-races around devconf->proxy_ndp

devconf->proxy_ndp can be read and written locklessly,
add appropriate annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: edumazet

net/ipv6/addrconf.c

@@ -561,7 +561,8 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		goto nla_put_failure;
 #endif
 	if ((all || type == NETCONFA_PROXY_NEIGH) &&
-	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0)
+	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
+			READ_ONCE(devconf->proxy_ndp)) < 0)
 		goto nla_put_failure;
 
 	if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&

net/ipv6/ip6_output.c

@@ -552,7 +552,7 @@ int ip6_forward(struct sk_buff *skb)
 	}
 
 	/* XXX: idev->cnf.proxy_ndp? */
-	if (net->ipv6.devconf_all->proxy_ndp &&
+	if (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) &&
 	    pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 		int proxied = ip6_forward_proxy_check(skb);
 		if (proxied > 0) {

net/ipv6/ndisc.c

@@ -904,7 +904,8 @@ static enum skb_drop_reason ndisc_recv_ns(struct sk_buff *skb)
 
 		if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
 		    (READ_ONCE(idev->cnf.forwarding) &&
-		     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
+		     (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) ||
+		      READ_ONCE(idev->cnf.proxy_ndp)) &&
 		     (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
 			if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
 			    skb->pkt_type != PACKET_HOST &&
@@ -1101,7 +1102,7 @@ static enum skb_drop_reason ndisc_recv_na(struct sk_buff *skb)
 		 */
 		if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
 		    READ_ONCE(net->ipv6.devconf_all->forwarding) &&
-		    net->ipv6.devconf_all->proxy_ndp &&
+		    READ_ONCE(net->ipv6.devconf_all->proxy_ndp) &&
 		    pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
 			/* XXX: idev->cnf.proxy_ndp */
 			goto out;