[PATCH 14/17] batman-adv: Use kref_get for _batadv_update_route
From: Antonio Quartulli <hidden>
Date: 2016-05-10 19:38:57
Subsystem:
batman advanced, the rest · Maintainers:
Marek Lindner, Simon Wunderlich, Antonio Quartulli, Sven Eckelmann, Linus Torvalds
From: Sven Eckelmann <sven@narfation.org> _batadv_update_route requires that the caller already has a valid reference for neigh_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> Signed-off-by: Marek Lindner <redacted> Signed-off-by: Antonio Quartulli <redacted> --- net/batman-adv/routing.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 2ecfca246be4..b494e435686f 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c@@ -100,10 +100,6 @@ static void _batadv_update_route(struct batadv_priv *bat_priv, if (curr_router) batadv_neigh_node_put(curr_router); - /* increase refcount of new best neighbor */ - if (neigh_node && !kref_get_unless_zero(&neigh_node->refcount)) - neigh_node = NULL; - spin_lock_bh(&orig_node->neigh_list_lock); /* curr_router used earlier may not be the current orig_ifinfo->router * anymore because it was dereferenced outside of the neigh_list_lock
@@ -114,6 +110,10 @@ static void _batadv_update_route(struct batadv_priv *bat_priv, */ curr_router = rcu_dereference_protected(orig_ifinfo->router, true); + /* increase refcount of new best neighbor */ + if (neigh_node) + kref_get(&neigh_node->refcount); + rcu_assign_pointer(orig_ifinfo->router, neigh_node); spin_unlock_bh(&orig_node->neigh_list_lock); batadv_orig_ifinfo_put(orig_ifinfo);
--
2.8.2