Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751604AbdIMAvN (ORCPT ); Tue, 12 Sep 2017 20:51:13 -0400 Received: from mail-oi0-f67.google.com ([209.85.218.67]:36329 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167AbdIMAvJ (ORCPT ); Tue, 12 Sep 2017 20:51:09 -0400 X-Google-Smtp-Source: AOwi7QAFDPbYUAB/i2zVnsBpxu4KmjKHd0pagX+9zJl3CrKK503vMMeCybaKTS0/D+XrcbQA9LHUXPssO9OD+viMaLs= MIME-Version: 1.0 In-Reply-To: <20170911192015.17553-1-christophe.jaillet@wanadoo.fr> References: <20170911192015.17553-1-christophe.jaillet@wanadoo.fr> From: Tonghao Zhang Date: Wed, 13 Sep 2017 08:51:07 +0800 Message-ID: Subject: Re: [PATCH] datapath: Fix an error handling path in 'ovs_nla_init_match_and_action()' To: Christophe JAILLET Cc: pravin shelar , David Miller , Linux Kernel Network Developers , ovs dev , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2201 Lines: 53 On Tue, Sep 12, 2017 at 3:20 AM, Christophe JAILLET wrote: > All other error handling paths in this function go through the 'error' > label. This one should do the same. > > Fixes: 9cc9a5cb176c ("datapath: Avoid using stack larger than 1024.") > Signed-off-by: Christophe JAILLET > --- > I think that the comment above the function could be improved. It looks > like the commit log which has introduced this function. > > I'm also not sure that commit 9cc9a5cb176c is of any help. It is > supposed to remove a warning, and I guess it does. But 'ovs_nla_init_match_and_action()' > is called unconditionnaly from 'ovs_flow_cmd_set()'. So even if the stack > used by each function is reduced, the overall stack should be the same, if > not larger. > > So this commit sounds like adding a bug where the code was fine and states > to fix an issue but, at the best, only hides it. > > Instead of fixing the code with the proposed patch, reverting the initial > commit could also be considered. > --- > net/openvswitch/datapath.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index 76cf273a56c7..c3aec6227c91 100644 > --- a/net/openvswitch/datapath.c > +++ b/net/openvswitch/datapath.c > @@ -1112,7 +1112,8 @@ static int ovs_nla_init_match_and_action(struct net *net, > if (!a[OVS_FLOW_ATTR_KEY]) { > OVS_NLERR(log, > "Flow key attribute not present in set flow."); > - return -EINVAL; > + error = -EINVAL; > + goto error; Thank for your report. But I really don't understand. In the 'ovs_nla_init_match_and_action', we only init 'match' when the OVS_FLOW_ATTR_KEY is set. If the 'OVS_FLOW_ATTR_ACTIONS' is set, but not 'OVS_FLOW_ATTR_KEY', we can return directly because the match is not inited yet, and it is unnecessary to set it's mask NULL. Then ovs_flow_cmd_set can run via value returned. > } > > *acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], key, > -- > 2.11.0 >