[LLC]: use rcu_dereference on receive handler

The receive hander pointer might be modified during network changes
of protocol. So use rcu_dereference (only matters on alpha).

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index d62e0f9b9da3..cb9f7f058f75 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -142,6 +142,8 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
         struct llc_sap *sap;
         struct llc_pdu_sn *pdu;
         int dest;
+        int (*rcv)(struct sk_buff *, struct net_device *,
+                   struct packet_type *, struct net_device *);
 
         /*
          * When the interface is in promisc. mode, drop all the crap that it
@@ -169,8 +171,9 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
          * First the upper layer protocols that don't need the full
          * LLC functionality
          */
-        if (sap->rcv_func) {
-                sap->rcv_func(skb, dev, pt, orig_dev);
+        rcv = rcu_dereference(sap->rcv_func);
+        if (rcv) {
+                rcv(skb, dev, pt, orig_dev);
                 goto out_put;
         }
         dest = llc_pdu_type(skb);