batman-adv: Increase orig_node refcount before releasing rcu read lock

When unicast_send_skb() is increasing the orig_node's refcount another
thread might have been freeing this orig_node already. We need to
increase the refcount in the rcu read lock protected area to avoid that.

Signed-off-by: Linus Lüssing <linus.luessing@ascom.ch>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index a3e842fd0f9c15a7d4d310bcdec4cd37bbeb4cfa..41eba8a660f58583c3790dd8090983eb7c253abb 100644 (file)
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -54,6 +54,9 @@ void *gw_get_selected(struct bat_priv *bat_priv)
 
        orig_node = curr_gateway_tmp->orig_node;
 
+       if (orig_node)
+               kref_get(&orig_node->refcount);
+
 out:
        rcu_read_unlock();
        return orig_node;

diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index 7ca994ccac1d04adc276f215c99cc4981995f12a..0603ceaeef622f1643247e7df61e05cba34cdfe0 100644 (file)
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -293,10 +293,9 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
        spin_lock_bh(&bat_priv->orig_hash_lock);
 
        /* get routing information */
-       if (is_multicast_ether_addr(ethhdr->h_dest))
+       if (is_multicast_ether_addr(ethhdr->h_dest)) {
                orig_node = (struct orig_node *)gw_get_selected(bat_priv);
-               if (orig_node) {
-                       kref_get(&orig_node->refcount);
+               if (orig_node)
                        goto find_router;
        }