From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752891AbeEOLj6 (ORCPT ); Tue, 15 May 2018 07:39:58 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:35544 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752831AbeEOLj4 (ORCPT ); Tue, 15 May 2018 07:39:56 -0400 X-Google-Smtp-Source: AB8JxZqIlR3jeHe/CybbiA5a0EMZ6LCqBF+bCowDMaFSPnrXnqSzusFAQH5K4GACP+28mfJeW+m8Cw== Date: Tue, 15 May 2018 13:39:54 +0200 From: Jiri Pirko To: Vlad Buslov Cc: netdev@vger.kernel.org, davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de, ast@kernel.org, daniel@iogearbox.net, edumazet@google.com, keescook@chromium.org, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, kliteyn@mellanox.com Subject: Re: [PATCH 07/14] net: sched: use reference counting action init Message-ID: <20180515113954.GM2134@nanopsycho.orion> References: <1526308035-12484-1-git-send-email-vladbu@mellanox.com> <1526308035-12484-8-git-send-email-vladbu@mellanox.com> <20180515112404.GL2134@nanopsycho.orion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tue, May 15, 2018 at 01:32:51PM CEST, vladbu@mellanox.com wrote: > >On Tue 15 May 2018 at 11:24, Jiri Pirko wrote: >> Mon, May 14, 2018 at 04:27:08PM CEST, vladbu@mellanox.com wrote: >>>Change action API to assume that action init function always takes >>>reference to action, even when overwriting existing action. This is >>>necessary because action API continues to use action pointer after init >>>function is done. At this point action becomes accessible for concurrent >>>modifications so user must always hold reference to it. >>> >>>Implement helper put list function to atomically release list of actions >>>after action API init code is done using them. >>> >>>Signed-off-by: Vlad Buslov >>>--- >>> net/sched/act_api.c | 38 +++++++++++++++++--------------------- >>> 1 file changed, 17 insertions(+), 21 deletions(-) >>> >> >> [...] >> >> >>>@@ -1196,8 +1190,7 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n, >>> return ret; >>> } >>> err: >>>- if (event != RTM_GETACTION) >> >> Howcome you do this for RTM_GETACTION now too? Where is the related >> "get"? > >In patch 5. There is always a possibility of concurrent delete without >rtnl lock so all usages of action pointers were converted to hold >reference to action. So that means that if you run kernel in between, with patch 5 but without patch 7 and you do RTM_GETACTION, you leak a reference, right? > >> >> >>>- tcf_action_destroy(&actions, 0); >>>+ tcf_action_put_lst(&actions); >>> return ret; >>> } >>> >> >> [...] >