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batman-adv: Use kref_get for _batadv_update_route

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_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 <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
This commit is contained in:
Sven Eckelmann 2016-03-05 19:05:24 +01:00 committed by Antonio Quartulli
parent 17a8691502
commit f0b94ebccd
1 changed files with 4 additions and 4 deletions
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8
net/batman-adv/routing.c
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@ -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);