From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43080 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753919AbcA0Gg1 (ORCPT ); Wed, 27 Jan 2016 01:36:27 -0500 Subject: Patch "batman-adv: Drop immediate batadv_hard_iface free function" has been added to the 4.4-stable tree To: sven@narfation.org, a@unstable.cc, gregkh@linuxfoundation.org, mareklindner@neomailbox.ch Cc: , From: Date: Tue, 26 Jan 2016 22:30:02 -0800 Message-ID: <14538762029712@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_hard_iface free function to the 4.4-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_hard_iface-free-function.patch and it can be found in the queue-4.4 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 21:31:27 PST 2016 From: Sven Eckelmann Date: Tue, 5 Jan 2016 12:06:25 +0100 Subject: batman-adv: Drop immediate batadv_hard_iface free function From: Sven Eckelmann [ Upstream commit b4d922cfc9c08318eeb77d53b7633740e6b0efb0 ] 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_hardif_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/hard-interface.h | 12 ------------ net/batman-adv/originator.c | 14 +++++++------- 2 files changed, 7 insertions(+), 19 deletions(-) --- a/net/batman-adv/hard-interface.h +++ b/net/batman-adv/hard-interface.h @@ -75,18 +75,6 @@ batadv_hardif_free_ref(struct batadv_har call_rcu(&hard_iface->rcu, batadv_hardif_free_rcu); } -/** - * batadv_hardif_free_ref_now - decrement the hard interface refcounter and - * possibly free it (without rcu callback) - * @hard_iface: the hard interface to free - */ -static inline void -batadv_hardif_free_ref_now(struct batadv_hard_iface *hard_iface) -{ - if (atomic_dec_and_test(&hard_iface->refcount)) - batadv_hardif_free_rcu(&hard_iface->rcu); -} - static inline struct batadv_hard_iface * batadv_primary_if_get_selected(struct batadv_priv *bat_priv) { --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -189,16 +189,16 @@ void batadv_neigh_ifinfo_free_ref(struct /** * batadv_neigh_node_free_rcu - free the neigh_node - * @rcu: rcu pointer of the neigh_node + * batadv_neigh_node_release - release neigh_node from lists and queue for + * free after rcu grace period + * @neigh_node: neigh neighbor to free */ -static void batadv_neigh_node_free_rcu(struct rcu_head *rcu) +static void batadv_neigh_node_release(struct batadv_neigh_node *neigh_node) { struct hlist_node *node_tmp; - struct batadv_neigh_node *neigh_node; struct batadv_neigh_ifinfo *neigh_ifinfo; struct batadv_algo_ops *bao; - neigh_node = container_of(rcu, struct batadv_neigh_node, rcu); bao = neigh_node->orig_node->bat_priv->bat_algo_ops; hlist_for_each_entry_safe(neigh_ifinfo, node_tmp, @@ -209,9 +209,9 @@ static void batadv_neigh_node_free_rcu(s if (bao->bat_neigh_free) bao->bat_neigh_free(neigh_node); - batadv_hardif_free_ref_now(neigh_node->if_incoming); + batadv_hardif_free_ref(neigh_node->if_incoming); - kfree(neigh_node); + kfree_rcu(neigh_node, rcu); } /** @@ -222,7 +222,7 @@ static void batadv_neigh_node_free_rcu(s void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node) { if (atomic_dec_and_test(&neigh_node->refcount)) - call_rcu(&neigh_node->rcu, batadv_neigh_node_free_rcu); + batadv_neigh_node_release(neigh_node); } /** Patches currently in stable-queue which might be from sven@narfation.org are queue-4.4/batman-adv-drop-immediate-batadv_neigh_node-free-function.patch queue-4.4/batman-adv-drop-immediate-neigh_ifinfo-free-function.patch queue-4.4/batman-adv-drop-immediate-orig_node-free-function.patch queue-4.4/batman-adv-drop-immediate-batadv_orig_ifinfo-free-function.patch queue-4.4/batman-adv-avoid-recursive-call_rcu-for-batadv_nc_node.patch queue-4.4/batman-adv-drop-immediate-batadv_hard_iface-free-function.patch queue-4.4/batman-adv-avoid-recursive-call_rcu-for-batadv_bla_claim.patch