From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Linus=20L=C3=BCssing?= Date: Sun, 17 Mar 2013 05:44:57 +0100 Message-Id: <1363495498-17830-1-git-send-email-linus.luessing@web.de> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: [B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: b.a.t.m.a.n@lists.open-mesh.org rcu_barrier() only waits for the currently scheduled rcu functions to finish - it won't wait for any function scheduled via another call_rcu() within an rcu scheduled function. Unfortunately our batadv_tt_orig_list_entry_free_ref() does just that, via a batadv_orig_node_free_ref() call, leading to our rcu_barrier() call potentially missing such a batadv_orig_node_free_ref(). This patch fixes this issue by calling the batadv_orig_node_free_rcu() directly from the rcu callback, removing the unnecessary, additional call_rcu() layer here. Signed-off-by: Linus Lüssing diff --git a/originator.c b/originator.c index 585e684..013c7d0 100644 --- a/originator.c +++ b/originator.c @@ -117,7 +117,7 @@ out: return neigh_node; } -static void batadv_orig_node_free_rcu(struct rcu_head *rcu) +void batadv_orig_node_free_rcu(struct rcu_head *rcu) { struct hlist_node *node_tmp; struct batadv_neigh_node *neigh_node, *tmp_neigh_node; diff --git a/originator.h b/originator.h index 7df48fa..4f9f88b 100644 --- a/originator.h +++ b/originator.h @@ -25,6 +25,7 @@ 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_rcu(struct rcu_head *rcu); void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node); struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, const uint8_t *addr); diff --git a/translation-table.c b/translation-table.c index 9322320..ee91cc1 100644 --- a/translation-table.c +++ b/translation-table.c @@ -144,7 +144,10 @@ 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); + + if (atomic_dec_and_test(&orig_entry->orig_node->refcount)) + batadv_orig_node_free_rcu(&orig_entry->orig_node->rcu); + kfree(orig_entry); } -- 1.7.10.4