1 files changed, 51 insertions, 41 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 4ef4bbdb49d4..0520aca3354b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -379,11 +379,8 @@ static void ip6_dst_destroy(struct dst_entry *dst)
 		in6_dev_put(idev);
 	}
 
-	rcu_read_lock();
-	from = rcu_dereference(rt->from);
-	rcu_assign_pointer(rt->from, NULL);
+	from = xchg((__force struct fib6_info **)&rt->from, NULL);
 	fib6_info_release(from);
-	rcu_read_unlock();
 }
 
 static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
@@ -1040,14 +1037,20 @@ static struct rt6_info *ip6_create_rt_rcu(struct fib6_info *rt)
 	struct rt6_info *nrt;
 
 	if (!fib6_info_hold_safe(rt))
-		return NULL;
+		goto fallback;
 
 	nrt = ip6_dst_alloc(dev_net(dev), dev, flags);
-	if (nrt)
-		ip6_rt_copy_init(nrt, rt);
-	else
+	if (!nrt) {
 		fib6_info_release(rt);
+		goto fallback;
+	}
+
+	ip6_rt_copy_init(nrt, rt);
+	return nrt;
 
+fallback:
+	nrt = dev_net(dev)->ipv6.ip6_null_entry;
+	dst_hold(&nrt->dst);
 	return nrt;
 }
 
@@ -1096,10 +1099,6 @@ restart:
 		dst_hold(&rt->dst);
 	} else {
 		rt = ip6_create_rt_rcu(f6i);
-		if (!rt) {
-			rt = net->ipv6.ip6_null_entry;
-			dst_hold(&rt->dst);
-		}
 	}
 
 	rcu_read_unlock();
@@ -1286,9 +1285,7 @@ static void rt6_remove_exception(struct rt6_exception_bucket *bucket,
 	/* purge completely the exception to allow releasing the held resources:
 	 * some [sk] cache may keep the dst around for unlimited time
 	 */
-	from = rcu_dereference_protected(rt6_ex->rt6i->from,
-					 lockdep_is_held(&rt6_exception_lock));
-	rcu_assign_pointer(rt6_ex->rt6i->from, NULL);
+	from = xchg((__force struct fib6_info **)&rt6_ex->rt6i->from, NULL);
 	fib6_info_release(from);
 	dst_dev_put(&rt6_ex->rt6i->dst);
 
@@ -2328,6 +2325,10 @@ static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
 
 		rcu_read_lock();
 		from = rcu_dereference(rt6->from);
+		if (!from) {
+			rcu_read_unlock();
+			return;
+		}
 		nrt6 = ip6_rt_cache_alloc(from, daddr, saddr);
 		if (nrt6) {
 			rt6_do_update_pmtu(nrt6, mtu);
@@ -3391,11 +3392,8 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 
 	rcu_read_lock();
 	from = rcu_dereference(rt->from);
-	/* This fib6_info_hold() is safe here because we hold reference to rt
-	 * and rt already holds reference to fib6_info.
-	 */
-	fib6_info_hold(from);
-	rcu_read_unlock();
+	if (!from)
+		goto out;
 
 	nrt = ip6_rt_cache_alloc(from, &msg->dest, NULL);
 	if (!nrt)
@@ -3407,10 +3405,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 
 	nrt->rt6i_gateway = *(struct in6_addr *)neigh->primary_key;
 
-	/* No need to remove rt from the exception table if rt is
-	 * a cached route because rt6_insert_exception() will
-	 * takes care of it
-	 */
+	/* rt6_insert_exception() will take care of duplicated exceptions */
 	if (rt6_insert_exception(nrt, from)) {
 		dst_release_immediate(&nrt->dst);
 		goto out;
@@ -3423,7 +3418,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 	call_netevent_notifiers(NETEVENT_REDIRECT, &netevent);
 
 out:
-	fib6_info_release(from);
+	rcu_read_unlock();
 	neigh_release(neigh);
 }
 
@@ -3662,23 +3657,34 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 
 static int ip6_pkt_drop(struct sk_buff *skb, u8 code, int ipstats_mib_noroutes)
 {
-	int type;
 	struct dst_entry *dst = skb_dst(skb);
+	struct net *net = dev_net(dst->dev);
+	struct inet6_dev *idev;
+	int type;
+
+	if (netif_is_l3_master(skb->dev) &&
+	    dst->dev == net->loopback_dev)
+		idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
+	else
+		idev = ip6_dst_idev(dst);
+
 	switch (ipstats_mib_noroutes) {
 	case IPSTATS_MIB_INNOROUTES:
 		type = ipv6_addr_type(&ipv6_hdr(skb)->daddr);
 		if (type == IPV6_ADDR_ANY) {
-			IP6_INC_STATS(dev_net(dst->dev),
-				      __in6_dev_get_safely(skb->dev),
-				      IPSTATS_MIB_INADDRERRORS);
+			IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 			break;
 		}
 		/* FALLTHROUGH */
 	case IPSTATS_MIB_OUTNOROUTES:
-		IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
-			      ipstats_mib_noroutes);
+		IP6_INC_STATS(net, idev, ipstats_mib_noroutes);
 		break;
 	}
+
+	/* Start over by dropping the dst for l3mdev case */
+	if (netif_is_l3_master(skb->dev))
+		skb_dst_drop(skb);
+
 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, code, 0);
 	kfree_skb(skb);
 	return 0;
@@ -5011,16 +5017,20 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
 	rcu_read_lock();
 	from = rcu_dereference(rt->from);
-
-	if (fibmatch)
-		err = rt6_fill_node(net, skb, from, NULL, NULL, NULL, iif,
-				    RTM_NEWROUTE, NETLINK_CB(in_skb).portid,
-				    nlh->nlmsg_seq, 0);
-	else
-		err = rt6_fill_node(net, skb, from, dst, &fl6.daddr,
-				    &fl6.saddr, iif, RTM_NEWROUTE,
-				    NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
-				    0);
+	if (from) {
+		if (fibmatch)
+			err = rt6_fill_node(net, skb, from, NULL, NULL, NULL,
+					    iif, RTM_NEWROUTE,
+					    NETLINK_CB(in_skb).portid,
+					    nlh->nlmsg_seq, 0);
+		else
+			err = rt6_fill_node(net, skb, from, dst, &fl6.daddr,
+					    &fl6.saddr, iif, RTM_NEWROUTE,
+					    NETLINK_CB(in_skb).portid,
+					    nlh->nlmsg_seq, 0);
+	} else {
+		err = -ENETUNREACH;
+	}
 	rcu_read_unlock();
 
 	if (err < 0) {