From patchwork Wed Jul 2 22:18:22 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 4468271 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3C0489F26C for ; Wed, 2 Jul 2014 22:18:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 704C720304 for ; Wed, 2 Jul 2014 22:18:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 281EB20225 for ; Wed, 2 Jul 2014 22:18:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751670AbaGBWSk (ORCPT ); Wed, 2 Jul 2014 18:18:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30627 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751303AbaGBWSk (ORCPT ); Wed, 2 Jul 2014 18:18:40 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s62MIS8T014557 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 2 Jul 2014 18:18:28 -0400 Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s62MIQau012401 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 2 Jul 2014 18:18:27 -0400 Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id s62MIQQX029056; Wed, 2 Jul 2014 18:18:26 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id s62MIMeA029051; Wed, 2 Jul 2014 18:18:22 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Wed, 2 Jul 2014 18:18:22 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Rickard Strandqvist cc: Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Jingoo Han , Alexandru Juncu , Daniel Vetter , Joe Perches , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] video: fbdev: matrox: matroxfb_base.c: Fix for possible null pointer dereference In-Reply-To: <1404337551-6499-1-git-send-email-rickard_strandqvist@spectrumdigital.se> Message-ID: References: <1404337551-6499-1-git-send-email-rickard_strandqvist@spectrumdigital.se> User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Wed, 2 Jul 2014, Rickard Strandqvist wrote: > Fix a possible null pointer dereference, there is otherwise a risk of a > possible null pointer dereference > > This was found using a static code analysis program called cppcheck > > Signed-off-by: Rickard Strandqvist > --- > drivers/video/fbdev/matrox/matroxfb_base.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/fbdev/matrox/matroxfb_base.c b/drivers/video/fbdev/matrox/matroxfb_base.c > index 7116c53..85ef84b 100644 > --- a/drivers/video/fbdev/matrox/matroxfb_base.c > +++ b/drivers/video/fbdev/matrox/matroxfb_base.c > @@ -1971,9 +1971,9 @@ static void matroxfb_register_device(struct matrox_fb_info* minfo) { > int i = 0; > list_add(&minfo->next_fb, &matroxfb_list); > for (drv = matroxfb_driver_l(matroxfb_driver_list.next); > - drv != matroxfb_driver_l(&matroxfb_driver_list); > + drv && drv != matroxfb_driver_l(&matroxfb_driver_list); The "drv" check is pointless because drv can't be NULL - use the patch below. > drv = matroxfb_driver_l(drv->node.next)) { > - if (drv && drv->probe) { > + if (drv->probe) { > void *p = drv->probe(minfo); > if (p) { > minfo->drivers_data[i] = p; > -- > 1.7.10.4 matroxfb: delete pointless NULL-pointer check The for loop walks a double-linked list, so drv cannot be NULL. This patch deletes the pointless NULL-pointer check. cppcheck warned about it. Signed-off-by: Mikulas Patocka --- drivers/video/fbdev/matrox/matroxfb_base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-2.6/drivers/video/fbdev/matrox/matroxfb_base.c =================================================================== --- linux-2.6.orig/drivers/video/fbdev/matrox/matroxfb_base.c 2014-06-19 16:41:45.048259897 +0200 +++ linux-2.6/drivers/video/fbdev/matrox/matroxfb_base.c 2014-07-03 00:13:04.299380130 +0200 @@ -1973,7 +1973,7 @@ static void matroxfb_register_device(str for (drv = matroxfb_driver_l(matroxfb_driver_list.next); drv != matroxfb_driver_l(&matroxfb_driver_list); drv = matroxfb_driver_l(drv->node.next)) { - if (drv && drv->probe) { + if (drv->probe) { void *p = drv->probe(minfo); if (p) { minfo->drivers_data[i] = p;