1 files changed, 21 insertions, 9 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 577b88a43293..753704f75b2c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -390,7 +390,13 @@ static inline int ip_rt_proc_init(void)
 
 static inline bool rt_is_expired(const struct rtable *rth)
 {
-	return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
+	bool res;
+
+	rcu_read_lock();
+	res = rth->rt_genid != rt_genid_ipv4(dev_net_rcu(rth->dst.dev));
+	rcu_read_unlock();
+
+	return res;
 }
 
 void rt_cache_flush(struct net *net)
@@ -1002,9 +1008,9 @@ out:	kfree_skb_reason(skb, reason);
 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 {
 	struct dst_entry *dst = &rt->dst;
-	struct net *net = dev_net(dst->dev);
 	struct fib_result res;
 	bool lock = false;
+	struct net *net;
 	u32 old_mtu;
 
 	if (ip_mtu_locked(dst))
@@ -1014,6 +1020,8 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 	if (old_mtu < mtu)
 		return;
 
+	rcu_read_lock();
+	net = dev_net_rcu(dst->dev);
 	if (mtu < net->ipv4.ip_rt_min_pmtu) {
 		lock = true;
 		mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
@@ -1021,9 +1029,8 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 
 	if (rt->rt_pmtu == mtu && !lock &&
 	    time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
-		return;
+		goto out;
 
-	rcu_read_lock();
 	if (fib_lookup(net, fl4, &res, 0) == 0) {
 		struct fib_nh_common *nhc;
 
@@ -1037,14 +1044,14 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 				update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
 						      jiffies + net->ipv4.ip_rt_mtu_expires);
 			}
-			rcu_read_unlock();
-			return;
+			goto out;
 		}
 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 		nhc = FIB_RES_NHC(res);
 		update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
 				      jiffies + net->ipv4.ip_rt_mtu_expires);
 	}
+out:
 	rcu_read_unlock();
 }
 
@@ -1307,10 +1314,15 @@ static void set_class_tag(struct rtable *rt, u32 tag)
 
 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
 {
-	struct net *net = dev_net(dst->dev);
 	unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
-	unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
-				    net->ipv4.ip_rt_min_advmss);
+	unsigned int advmss;
+	struct net *net;
+
+	rcu_read_lock();
+	net = dev_net_rcu(dst->dev);
+	advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
+				   net->ipv4.ip_rt_min_advmss);
+	rcu_read_unlock();
 
 	return min(advmss, IPV4_MAX_PMTU - header_size);
 }