diff mbox

[8/9] batman-adv: Use kref_get for batadv_gw_node_add

Message ID 1457190564-11419-8-git-send-email-sven@narfation.org (mailing list archive)
State Accepted, archived
Commit 25a303d311c76f749ccd96a45b458eaf560e6243
Delegated to: Marek Lindner
Headers

Commit Message

Sven Eckelmann March 5, 2016, 3:09 p.m. UTC 
  batadv_gw_node_add requires that the caller already has a valid reference
for orig_node. It is therefore not possible that it has an reference
counter of 0 and was still given to this function

The kref_get function instead WARNs (with debug information) when the
reference counter would still be 0. This makes a bug in batman-adv better
visible because kref_get_unless_zero would have ignored this problem.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/gateway_client.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

Comments

Marek Lindner April 11, 2016, 10:29 a.m. UTC | #1 
On Saturday, March 05, 2016 16:09:23 Sven Eckelmann wrote:
> batadv_gw_node_add requires that the caller already has a valid reference
> for orig_node. It is therefore not possible that it has an reference
> counter of 0 and was still given to this function
> 
> The kref_get function instead WARNs (with debug information) when the
> reference counter would still be 0. This makes a bug in batman-adv better
> visible because kref_get_unless_zero would have ignored this problem.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
>  net/batman-adv/gateway_client.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)

Applied in revision 25a303d.

Thanks,
Marek
diff mbox

Patch

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index bb1c4f3..5839c56 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -440,15 +440,11 @@  static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 	if (gateway->bandwidth_down == 0)
 		return;
 
-	if (!kref_get_unless_zero(&orig_node->refcount))
-		return;
-
 	gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
-	if (!gw_node) {
-		batadv_orig_node_put(orig_node);
+	if (!gw_node)
 		return;
-	}
 
+	kref_get(&orig_node->refcount);
 	INIT_HLIST_NODE(&gw_node->list);
 	gw_node->orig_node = orig_node;
 	gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);