Merge tag 'batman-adv-fix-for-davem' of git://git.open-mesh.org/linux-merge

Included changes:
- fix global protection fault by avoiding double call_rcu

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 23 insertions, 1 deletions

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 2f3452546636..fad1a2093e15 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -156,12 +156,28 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
         kfree(orig_node);
 }
 
+/**
+ * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly
+ * schedule an rcu callback for freeing it
+ * @orig_node: the orig node to free
+ */
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 {
         if (atomic_dec_and_test(&orig_node->refcount))
                 call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
 }
 
+/**
+ * batadv_orig_node_free_ref_now - decrement the orig node refcounter and
+ * possibly free it (without rcu callback)
+ * @orig_node: the orig node to free
+ */
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node)
+{
+        if (atomic_dec_and_test(&orig_node->refcount))
+                batadv_orig_node_free_rcu(&orig_node->rcu);
+}
+
 void batadv_originator_free(struct batadv_priv *bat_priv)
 {
         struct batadv_hashtable *hash = bat_priv->orig_hash;
diff --git a/net/batman-adv/originator.h b/net/batman-adv/originator.h
index 7df48fa7669d..734e5a3d8a5b 100644
--- a/net/batman-adv/originator.h
+++ b/net/batman-adv/originator.h
@@ -26,6 +26,7 @@ int batadv_originator_init(struct batadv_priv *bat_priv);
 void batadv_originator_free(struct batadv_priv *bat_priv);
 void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node);
 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
                                               const uint8_t *addr);
 struct batadv_neigh_node *
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 5e89deeb9542..9e8748575845 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -144,7 +144,12 @@ static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
         struct batadv_tt_orig_list_entry *orig_entry;
 
         orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu);
-        batadv_orig_node_free_ref(orig_entry->orig_node);
+
+        /* We are in an rcu callback here, therefore we cannot use
+         * batadv_orig_node_free_ref() and its call_rcu():
+         * An rcu_barrier() wouldn't wait for that to finish
+         */
+        batadv_orig_node_free_ref_now(orig_entry->orig_node);
         kfree(orig_entry);
 }