1 files changed, 21 insertions, 19 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 878a08c40fff..5319093d9aa6 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -399,7 +399,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)raw;
 	unsigned int nhoff = raw - skb->data;
 	unsigned int off = nhoff + sizeof(*ipv6h);
-	u8 next, nexthdr = ipv6h->nexthdr;
+	u8 nexthdr = ipv6h->nexthdr;
 
 	while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
 		struct ipv6_opt_hdr *hdr;
@@ -410,25 +410,25 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
 
 		hdr = (struct ipv6_opt_hdr *)(skb->data + off);
 		if (nexthdr == NEXTHDR_FRAGMENT) {
-			struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
-			if (frag_hdr->frag_off)
-				break;
 			optlen = 8;
 		} else if (nexthdr == NEXTHDR_AUTH) {
 			optlen = ipv6_authlen(hdr);
 		} else {
 			optlen = ipv6_optlen(hdr);
 		}
-		/* cache hdr->nexthdr, since pskb_may_pull() might
-		 * invalidate hdr
-		 */
-		next = hdr->nexthdr;
-		if (nexthdr == NEXTHDR_DEST) {
-			u16 i = 2;
 
-			/* Remember : hdr is no longer valid at this point. */
-			if (!pskb_may_pull(skb, off + optlen))
+		if (!pskb_may_pull(skb, off + optlen))
+			break;
+
+		hdr = (struct ipv6_opt_hdr *)(skb->data + off);
+		if (nexthdr == NEXTHDR_FRAGMENT) {
+			struct frag_hdr *frag_hdr = (struct frag_hdr *)hdr;
+
+			if (frag_hdr->frag_off)
 				break;
+		}
+		if (nexthdr == NEXTHDR_DEST) {
+			u16 i = 2;
 
 			while (1) {
 				struct ipv6_tlv_tnl_enc_lim *tel;
@@ -449,7 +449,7 @@ __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
 					i++;
 			}
 		}
-		nexthdr = next;
+		nexthdr = hdr->nexthdr;
 		off += optlen;
 	}
 	return 0;
@@ -1201,8 +1201,8 @@ route_lookup:
 	 */
 	max_headroom = LL_RESERVED_SPACE(dst->dev) + sizeof(struct ipv6hdr)
 			+ dst->header_len + t->hlen;
-	if (max_headroom > dev->needed_headroom)
-		dev->needed_headroom = max_headroom;
+	if (max_headroom > READ_ONCE(dev->needed_headroom))
+		WRITE_ONCE(dev->needed_headroom, max_headroom);
 
 	err = ip6_tnl_encap(skb, t, &proto, fl6);
 	if (err)
@@ -1430,6 +1430,7 @@ static void ip6_tnl_link_config(struct ip6_tnl *t)
 	struct __ip6_tnl_parm *p = &t->parms;
 	struct flowi6 *fl6 = &t->fl.u.ip6;
 	int t_hlen;
+	int mtu;
 
 	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
@@ -1472,12 +1473,13 @@ static void ip6_tnl_link_config(struct ip6_tnl *t)
 			dev->hard_header_len = rt->dst.dev->hard_header_len +
 				t_hlen;
 
-			dev->mtu = rt->dst.dev->mtu - t_hlen;
+			mtu = rt->dst.dev->mtu - t_hlen;
 			if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
-				dev->mtu -= 8;
+				mtu -= 8;
 
-			if (dev->mtu < IPV6_MIN_MTU)
-				dev->mtu = IPV6_MIN_MTU;
+			if (mtu < IPV6_MIN_MTU)
+				mtu = IPV6_MIN_MTU;
+			WRITE_ONCE(dev->mtu, mtu);
 		}
 		ip6_rt_put(rt);
 	}