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authorSven Eckelmann <sven@narfation.org>2016-01-05 12:06:22 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-31 11:29:02 -0800
commit31459b9b4502c50140e2e16373bb59121d5ac293 (patch)
treed48603759b14f754fe4a5018261591e3618e6a88 /net/batman-adv
parent53ab5ef03bf07b96b6c595efc941c8d06e76858c (diff)
batman-adv: Drop immediate batadv_neigh_node free function
[ Upstream commit 2baa753c276f27f8e844637561ad597867aa6fb6 ] 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_neigh_node_free_ref. Fixes: 89652331c00f ("batman-adv: split tq information in neigh_node struct") 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>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/originator.c33
1 files changed, 10 insertions, 23 deletions
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index a0728948fada..a8e68eba8349 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -229,20 +229,8 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu)
}
/**
- * batadv_neigh_node_free_ref_now - decrement the neighbors refcounter
- * and possibly free it (without rcu callback)
- * @neigh_node: neigh neighbor to free
- */
-static void
-batadv_neigh_node_free_ref_now(struct batadv_neigh_node *neigh_node)
-{
- if (atomic_dec_and_test(&neigh_node->refcount))
- batadv_neigh_node_free_rcu(&neigh_node->rcu);
-}
-
-/**
* batadv_neigh_node_free_ref - decrement the neighbors refcounter
- * and possibly free it
+ * and possibly release it
* @neigh_node: neigh neighbor to free
*/
void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
@@ -532,24 +520,23 @@ out:
}
/**
- * batadv_orig_ifinfo_free_rcu - free the orig_ifinfo object
- * @rcu: rcu pointer of the orig_ifinfo object
+ * batadv_orig_ifinfo_release - release orig_ifinfo from lists and queue for
+ * free after rcu grace period
+ * @orig_ifinfo: the orig_ifinfo object to release
*/
-static void batadv_orig_ifinfo_free_rcu(struct rcu_head *rcu)
+static void batadv_orig_ifinfo_release(struct batadv_orig_ifinfo *orig_ifinfo)
{
- struct batadv_orig_ifinfo *orig_ifinfo;
struct batadv_neigh_node *router;
- orig_ifinfo = container_of(rcu, struct batadv_orig_ifinfo, rcu);
-
if (orig_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
- batadv_hardif_free_ref_now(orig_ifinfo->if_outgoing);
+ batadv_hardif_free_ref(orig_ifinfo->if_outgoing);
/* this is the last reference to this object */
router = rcu_dereference_protected(orig_ifinfo->router, true);
if (router)
- batadv_neigh_node_free_ref_now(router);
- kfree(orig_ifinfo);
+ batadv_neigh_node_free_ref(router);
+
+ kfree_rcu(orig_ifinfo, rcu);
}
/**
@@ -560,7 +547,7 @@ static void batadv_orig_ifinfo_free_rcu(struct rcu_head *rcu)
void batadv_orig_ifinfo_free_ref(struct batadv_orig_ifinfo *orig_ifinfo)
{
if (atomic_dec_and_test(&orig_ifinfo->refcount))
- call_rcu(&orig_ifinfo->rcu, batadv_orig_ifinfo_free_rcu);
+ batadv_orig_ifinfo_release(orig_ifinfo);
}
/**