From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42812 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753793AbcA0GdR (ORCPT ); Wed, 27 Jan 2016 01:33:17 -0500 Subject: Patch "batman-adv: Drop immediate batadv_neigh_node free function" has been added to the 4.3-stable tree To: sven@narfation.org, a@unstable.cc, gregkh@linuxfoundation.org, mareklindner@neomailbox.ch Cc: , From: Date: Tue, 26 Jan 2016 22:28:56 -0800 Message-ID: <145387613620245@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled batman-adv: Drop immediate batadv_neigh_node free function to the 4.3-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: batman-adv-drop-immediate-batadv_neigh_node-free-function.patch and it can be found in the queue-4.3 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Tue Jan 26 21:35:03 PST 2016 From: Sven Eckelmann Date: Tue, 5 Jan 2016 12:06:22 +0100 Subject: batman-adv: Drop immediate batadv_neigh_node free function From: Sven Eckelmann [ 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 Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/originator.c | 33 ++++++++++----------------------- 1 file changed, 10 insertions(+), 23 deletions(-) --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -229,20 +229,8 @@ static void batadv_neigh_node_free_rcu(s } /** - * 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( 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); } /** Patches currently in stable-queue which might be from sven@narfation.org are queue-4.3/batman-adv-drop-immediate-batadv_neigh_node-free-function.patch queue-4.3/batman-adv-drop-immediate-neigh_ifinfo-free-function.patch queue-4.3/batman-adv-drop-immediate-orig_node-free-function.patch queue-4.3/batman-adv-drop-immediate-batadv_orig_ifinfo-free-function.patch queue-4.3/batman-adv-avoid-recursive-call_rcu-for-batadv_nc_node.patch queue-4.3/batman-adv-drop-immediate-batadv_hard_iface-free-function.patch queue-4.3/batman-adv-avoid-recursive-call_rcu-for-batadv_bla_claim.patch