diff mbox

[7/9] batman-adv: Use kref_get for batadv_gw_select

Message ID 1457190564-11419-7-git-send-email-sven@narfation.org
State Accepted, archived
Commit e698321151040710f632bf8c014ec23c5bc406c8
Delegated to: Marek Lindner
Headers show

Commit Message

Sven Eckelmann March 5, 2016, 3:09 p.m. UTC
batadv_gw_select requires that the caller already has a valid reference for
new_gw_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 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Marek Lindner April 11, 2016, 10:25 a.m. UTC | #1
On Saturday, March 05, 2016 16:09:22 Sven Eckelmann wrote:
> batadv_gw_select requires that the caller already has a valid reference for
> new_gw_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 | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied in revision e698321.

Thanks,
Marek
diff mbox

Patch

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index c59aff5..bb1c4f3 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -135,8 +135,8 @@  static void batadv_gw_select(struct batadv_priv *bat_priv,
 
 	spin_lock_bh(&bat_priv->gw.list_lock);
 
-	if (new_gw_node && !kref_get_unless_zero(&new_gw_node->refcount))
-		new_gw_node = NULL;
+	if (new_gw_node)
+		kref_get(&new_gw_node->refcount);
 
 	curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
 	rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);