From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755673Ab3AQNQK (ORCPT ); Thu, 17 Jan 2013 08:16:10 -0500 Received: from mail-qa0-f46.google.com ([209.85.216.46]:60205 "EHLO mail-qa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751814Ab3AQNQI (ORCPT ); Thu, 17 Jan 2013 08:16:08 -0500 Date: Thu, 17 Jan 2013 13:16:04 +0000 From: Cong Ding To: Richard Mortimer Cc: Sam Ravnborg , "David S. Miller" , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] sparc: kernel/sbus.c: fix memory leakage Message-ID: <20130117131604.GC25615@gmail.com> References: <1358199372-11976-1-git-send-email-dinggnu@gmail.com> <20130116211309.GA13993@merkur.ravnborg.org> <20130116211725.GC18593@gmail.com> <20130116220018.GA14063@merkur.ravnborg.org> <20130116220153.GD18593@gmail.com> <50F7D577.8010506@oldelvet.org.uk> <20130117115637.GB25615@gmail.com> <50F7EED3.1050309@oldelvet.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50F7EED3.1050309@oldelvet.org.uk> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 17, 2013 at 12:30:11PM +0000, Richard Mortimer wrote: > > > On 17/01/2013 11:56, Cong Ding wrote: > >On Thu, Jan 17, 2013 at 10:41:59AM +0000, Richard Mortimer wrote: > >> > >> > >>On 16/01/2013 22:01, Cong Ding wrote: > >>>the variable iommu and strbuf are not freed if it goes to error. > >>> > >>>Signed-off-by: Cong Ding > >>>--- > >>> arch/sparc/kernel/sbus.c | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>>diff --git a/arch/sparc/kernel/sbus.c b/arch/sparc/kernel/sbus.c > >>>index 1271b3a..78aa26b 100644 > >>>--- a/arch/sparc/kernel/sbus.c > >>>+++ b/arch/sparc/kernel/sbus.c > >>>@@ -656,6 +656,8 @@ static void __init sbus_iommu_init(struct platform_device *op) > >>> return; > >>> > >>> fatal_memory_error: > >>>+ kfree(strbuf); > >> > >>strbuf will be uninitialized if the iommu allocation fails. I don't > >>have a particular preference for how to fix this but tend to dislike > >>initial assignment with NULL because it hides other control flow > >>issues. > >Sorry I didn't notice strbuf will be uninitialized here. But if we don't > >initially assign a NULL value to strbuf, I cannot find a way to handle it > >besides the first version patch. Did you have any suggestions? For me, I like > >the first version. > > Two thoughts... > > 1 - just use a goto target for the iommu allocation failure and make > that skip the strbuf free call. The others use the existing > fatal_memory_error label. this looks ugly. If we do in this way, why not version 1? > > 2 - Move the strbuf kzalloc up 2 lines so that it occurs before the > test for iommu. > > 2b - In case (2) above the failure test could be changed to > if (!iommu || !strbuf) > to remove duplication of goto. I will send a new version by using this solution. Thanks, - cong