From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757150AbcAYMvJ (ORCPT ); Mon, 25 Jan 2016 07:51:09 -0500 Received: from foss.arm.com ([217.140.101.70]:37094 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757081AbcAYMvH (ORCPT ); Mon, 25 Jan 2016 07:51:07 -0500 Date: Mon, 25 Jan 2016 12:51:05 +0000 From: liviu.dudau@arm.com To: Julia Lawall Cc: Amitoj Kaur Chawla , sudeep.holla@arm.com, lorenzo.pieralisi@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] bus: vexpress-config: Add missing of_node_put Message-ID: <20160125125104.GD1194@e106497-lin.cambridge.arm.com> References: <20160122180838.GA12069@amitoj-Inspiron-3542> <20160125121720.GC1194@e106497-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 25, 2016 at 01:24:44PM +0100, Julia Lawall wrote: > > > On Mon, 25 Jan 2016, liviu.dudau@arm.com wrote: > > > On Fri, Jan 22, 2016 at 11:38:38PM +0530, Amitoj Kaur Chawla wrote: > > > for_each_compatible_node performs an of_node_get on each iteration, so > > > to break out of the loop an of_node_put is required. > > > > > > Found using Coccinelle. The semantic patch used for this is as follows: > > > > > > // > > > @@ > > > expression e; > > > local idexpression n; > > > @@ > > > > > > for_each_compatible_node(n, ...) { > > > ... when != of_node_put(n) > > > when != e = n > > > ( > > > return n; > > > + of_node_put(n); > > > ? return ...; > > > ) > > > ... > > > } > > > // > > > > > > Signed-off-by: Amitoj Kaur Chawla > > > > Hi Amitoj, > > > > > --- > > > drivers/bus/vexpress-config.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/bus/vexpress-config.c b/drivers/bus/vexpress-config.c > > > index 6575c0f..c3cb76b 100644 > > > --- a/drivers/bus/vexpress-config.c > > > +++ b/drivers/bus/vexpress-config.c > > > @@ -192,8 +192,10 @@ static int __init vexpress_config_init(void) > > > /* Need the config devices early, before the "normal" devices... */ > > > for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") { > > > err = vexpress_config_populate(node); > > > - if (err) > > > + if (err) { > > > + of_node_put(node); > > > break; > > > + } > > > > This automatically generated patch only solves half of the problem (for the error > > path). > > > > > } > > > > > > return err; > > > -- > > > 1.9.1 > > > > > > > I feel that a better patch would be the following, where the node is released > > regardless of the result of vexpress_config_populate(). > > > > --8<-------------------------------------------------------------------------- > > diff --git a/drivers/bus/vexpress-config.c b/drivers/bus/vexpress-config.c > > index 6575c0f..c57453d 100644 > > --- a/drivers/bus/vexpress-config.c > > +++ b/drivers/bus/vexpress-config.c > > @@ -192,6 +192,7 @@ static int __init vexpress_config_init(void) > > /* Need the config devices early, before the "normal" devices... */ > > for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") { > > err = vexpress_config_populate(node); > > + of_node_put(node); > > This is not correct. for_each_compatible_node will do the free if you go > around the loop. This change would lead to a double free in the non error > case. You are correct and I withdraw my patch. For the original patch: Acked-by: Liviu Dudau Best regards, Liviu > > julia > > > if (err) > > break; > > } > > -->8-------------------------------------------------------------------------- -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯