From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] net/sched: cls_flower: verify root pointer before dereferncing it Date: Tue, 22 Nov 2016 10:37:42 -0500 (EST) Message-ID: <20161122.103742.1421376877129949203.davem@davemloft.net> References: <1479824726-62607-1-git-send-email-roid@mellanox.com> <20161122144844.GB1819@nanopsycho> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: roid@mellanox.com, netdev@vger.kernel.org, jiri@mellanox.com, xiyou.wangcong@gmail.com, ogerlitz@mellanox.com, cwang@twopensource.com To: jiri@resnulli.us Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:53830 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755665AbcKVPhu (ORCPT ); Tue, 22 Nov 2016 10:37:50 -0500 In-Reply-To: <20161122144844.GB1819@nanopsycho> Sender: netdev-owner@vger.kernel.org List-ID: From: Jiri Pirko Date: Tue, 22 Nov 2016 15:48:44 +0100 > Tue, Nov 22, 2016 at 03:25:26PM CET, roid@mellanox.com wrote: >>tp->root is being allocated in init() time and kfreed in destroy() >>however it is being dereferenced in classify() path. >> >>We could be in classify() path after destroy() was called and thus >>tp->root is null. Verifying if tp->root is null in classify() path >>is enough because it's being freed with kfree_rcu() and classify() >>path is under rcu_read_lock(). >> >>Fixes: 1e052be69d04 ("net_sched: destroy proto tp when all filters are gone") >>Signed-off-by: Roi Dayan >>Cc: Cong Wang > > This is correct > > Reviewed-by: Jiri Pirko > > The other way to fix this would be to move tp->ops->destroy call to > call_rcu phase. That would require bigger changes though. net-next > perhaps? This patch is targetted at net-next as per Subj.