From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932560AbcAYMZN (ORCPT ); Mon, 25 Jan 2016 07:25:13 -0500 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:56526 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932102AbcAYMZK (ORCPT ); Mon, 25 Jan 2016 07:25:10 -0500 X-IronPort-AV: E=Sophos;i="5.22,344,1449529200"; d="scan'208";a="199130006" Date: Mon, 25 Jan 2016 13:24:44 +0100 (CET) From: Julia Lawall X-X-Sender: jll@hadrien To: liviu.dudau@arm.com 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 In-Reply-To: <20160125121720.GC1194@e106497-lin.cambridge.arm.com> Message-ID: References: <20160122180838.GA12069@amitoj-Inspiron-3542> <20160125121720.GC1194@e106497-lin.cambridge.arm.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323329-731092834-1453724684=:2510" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-731092834-1453724684=:2510 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT 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. julia > if (err) > break; > } > -->8-------------------------------------------------------------------------- > > Best regards, > Liviu > > -- > ==================== > | I would like to | > | fix the world, | > | but they're not | > | giving me the | > \ source code! / > --------------- > ¯\_(ツ)_/¯ > --8323329-731092834-1453724684=:2510--