geneve: lock RCU on TX path

[ Upstream commit a717e3f7 ]

There is no guarantees that callers of the TX path will hold
the RCU lock.  Grab it explicitly.

Fixes: fceb9c3e ("geneve: avoid using stale geneve socket.")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/geneve.c

@@ -1039,16 +1039,22 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct geneve_dev *geneve = netdev_priv(dev);
 	struct ip_tunnel_info *info = NULL;
+	int err;
 
 	if (geneve->collect_md)
 		info = skb_tunnel_info(skb);
 
+	rcu_read_lock();
 #if IS_ENABLED(CONFIG_IPV6)
 	if ((info && ip_tunnel_info_af(info) == AF_INET6) ||
 	    (!info && geneve->remote.sa.sa_family == AF_INET6))
-		return geneve6_xmit_skb(skb, dev, info);
+		err = geneve6_xmit_skb(skb, dev, info);
+	else
 #endif
-	return geneve_xmit_skb(skb, dev, info);
+		err = geneve_xmit_skb(skb, dev, info);
+	rcu_read_unlock();
+
+	return err;
 }
 
 static int __geneve_change_mtu(struct net_device *dev, int new_mtu, bool strict)