[B.A.T.M.A.N.] [PATCHv2 7/7] batman-adv: Increase orig_node refcount before releasing rcu read lock

["Linus Lüssing" <linus.luessing@ascom.ch>]

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.

The same is true for get_orig_node().

Signed-off-by: Linus Lüssing <linus.luessing@ascom.ch>
---
 gateway_client.c |    3 +++
 originator.c     |    4 ++--
 unicast.c        |    1 -
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/batman-adv/gateway_client.c b/batman-adv/gateway_client.c
index 4624515..b3cda22 100644
--- a/batman-adv/gateway_client.c
+++ b/batman-adv/gateway_client.c
@@ -55,6 +55,9 @@ void *gw_get_selected(struct bat_priv *bat_priv)
 	}
 
 	orig_node = curr_gateway_tmp->orig_node;
+	if (orig_node)
+		kref_get(&orig_node->refcount);
+
 	rcu_read_unlock();
 
 	return orig_node;
diff --git a/batman-adv/originator.c b/batman-adv/originator.c
index bde9778..6fb8393 100644
--- a/batman-adv/originator.c
+++ b/batman-adv/originator.c
@@ -193,12 +193,12 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
 	orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
 						   compare_orig, choose_orig,
 						   addr));
-	rcu_read_unlock();
-
 	if (orig_node) {
 		kref_get(&orig_node->refcount);
+		rcu_read_unlock();
 		return orig_node;
 	}
+	rcu_read_unlock();
 
 	bat_dbg(DBG_BATMAN, bat_priv,
 		"Creating new originator: %pM\n", addr);
diff --git a/batman-adv/unicast.c b/batman-adv/unicast.c
index 580b547..f4f5115 100644
--- a/batman-adv/unicast.c
+++ b/batman-adv/unicast.c
@@ -298,7 +298,6 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 		if (!orig_node)
 			goto trans_search;
 
-		kref_get(&orig_node->refcount);
 		goto find_router;
 	} else {
 		rcu_read_lock();
-- 
1.7.2.3