From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753864AbbKLIDN (ORCPT ); Thu, 12 Nov 2015 03:03:13 -0500 Received: from mail-wm0-f41.google.com ([74.125.82.41]:36281 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753379AbbKLIDM (ORCPT ); Thu, 12 Nov 2015 03:03:12 -0500 MIME-Version: 1.0 In-Reply-To: <1447314423-31225-1-git-send-email-clabbe.montjoie@gmail.com> References: <1447314423-31225-1-git-send-email-clabbe.montjoie@gmail.com> Date: Thu, 12 Nov 2015 09:03:11 +0100 Message-ID: Subject: Re: [PATCH] mtd: nand: mxc_nand: fix a possible NULL dereference From: Frans Klaver To: LABBE Corentin Cc: baruch@tkos.co.il, Brian Norris , David Woodhouse , =?UTF-8?Q?Krzysztof_Koz=C5=82owski?= , Luis de Bethencourt , s.hauer@pengutronix.de, u.kleine-koenig@pengutronix.de, "linux-kernel@vger.kernel.org" , linux-mtd@lists.infradead.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 Hi, On Thu, Nov 12, 2015 at 8:46 AM, LABBE Corentin wrote: > of_match_device could return NULL, and so cause a NULL pointer > dereference later. Did you actually run into this? It seems to me that this driver is only probed if and only if we have a match and that therefore of_match_device will always return a valid pointer (it is using the same match table). Am I missing something? > Signed-off-by: LABBE Corentin > --- > drivers/mtd/nand/mxc_nand.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c > index 136e73a..9e42431 100644 > --- a/drivers/mtd/nand/mxc_nand.c > +++ b/drivers/mtd/nand/mxc_nand.c > @@ -1464,8 +1464,7 @@ static int __init mxcnd_probe_dt(struct mxc_nand_host *host) > { > struct device_node *np = host->dev->of_node; > struct mxc_nand_platform_data *pdata = &host->pdata; > - const struct of_device_id *of_id = > - of_match_device(mxcnd_dt_ids, host->dev); > + const struct of_device_id *of_id; > int buswidth; > > if (!np) > @@ -1482,6 +1481,9 @@ static int __init mxcnd_probe_dt(struct mxc_nand_host *host) > > pdata->width = buswidth / 8; > > + of_id = of_match_device(mxcnd_dt_ids, host->dev); > + if (!of_id) > + return -ENODEV; > host->devtype_data = of_id->data; > > return 0; > -- > 2.4.10 > Thanks, Frans