batman-adv: Drop immediate orig_node free function

Orabug: 23330576

[ Upstream commit 42eff6a617e23b691f8e4467f4687ed7245a92db ]

It is not allowed to free the memory of an object which is part of a list
which is protected by rcu-read-side-critical sections without making sure
that no other context is accessing the object anymore. This usually happens
by removing the references to this object and then waiting until the rcu
grace period is over and no one (allowedly) accesses it anymore.

But the _now functions ignore this completely. They free the object
directly even when a different context still tries to access it. This has
to be avoided and thus these functions must be removed and all functions
have to use batadv_orig_node_free_ref.

Fixes: 72822225bd41 ("batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 95785b105fa2f784ad7b6be0238338b648ed892a)

Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 36dfa3bac2b708a4bc4e8194a3f0185ab43954f8..77ea1d4de2ba8677d478732066c57f14673347e7 100644 (file)
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -562,17 +562,6 @@ void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
                batadv_orig_node_release(orig_node);
 }
 
-/**
- * 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 aa4a4369629569840e310acc2c6e6619f49a5768..28b751ad549cc82d25273e88c2c7e250a9efa874 100644 (file)
--- a/net/batman-adv/originator.h
+++ b/net/batman-adv/originator.h
@@ -25,7 +25,6 @@ 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_orig_node_new(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 4f2a9d2c56dbba0f7845ef747e94c7c53576d5c8..ddd62c9af5b4ce61c453c529116a25ef11bf6f31 100644 (file)
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -219,20 +219,6 @@ int batadv_tt_global_hash_count(struct batadv_priv *bat_priv,
        return count;
 }
 
-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);
-
-       /* 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);
-}
-
 /**
  * batadv_tt_local_size_mod - change the size by v of the local table identified
  *  by vid
@@ -328,13 +314,25 @@ static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node,
        batadv_tt_global_size_mod(orig_node, vid, -1);
 }
 
+/**
+ * batadv_tt_orig_list_entry_release - release tt orig entry from lists and
+ *  queue for free after rcu grace period
+ * @orig_entry: tt orig entry to be free'd
+ */
+static void
+batadv_tt_orig_list_entry_release(struct batadv_tt_orig_list_entry *orig_entry)
+{
+       batadv_orig_node_free_ref(orig_entry->orig_node);
+       kfree_rcu(orig_entry, rcu);
+}
+
 static void
 batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry)
 {
        if (!atomic_dec_and_test(&orig_entry->refcount))
                return;
 
-       call_rcu(&orig_entry->rcu, batadv_tt_orig_list_entry_free_rcu);
+       batadv_tt_orig_list_entry_release(orig_entry);
 }
 
 /**