From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754273AbbKLKO3 (ORCPT ); Thu, 12 Nov 2015 05:14:29 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:33817 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753028AbbKLKO2 (ORCPT ); Thu, 12 Nov 2015 05:14:28 -0500 Date: Thu, 12 Nov 2015 11:14:18 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: LABBE Corentin Cc: LABBE Corentin , baruch@tkos.co.il, computersforpeace@gmail.com, dwmw2@infradead.org, fransklaver@gmail.com, k.kozlowski.k@gmail.com, luis@debethencourt.com, s.hauer@pengutronix.de, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org Subject: Re: [PATCH] mtd: nand: mxc_nand: fix a possible NULL dereference Message-ID: <20151112101418.GI24008@pengutronix.de> References: <1447314423-31225-1-git-send-email-clabbe.montjoie@gmail.com> <20151112081909.GD24008@pengutronix.de> <20151112100328.GC9850@Red> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20151112100328.GC9850@Red> User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, Nov 12, 2015 at 11:03:28AM +0100, LABBE Corentin wrote: > On Thu, Nov 12, 2015 at 09:19:09AM +0100, Uwe Kleine-König wrote: > > Hello Corentin, > > > > On Thu, Nov 12, 2015 at 08:46:55AM +0100, LABBE Corentin wrote: > > > of_match_device could return NULL, and so cause a NULL pointer > > > dereference later. > > > > > > 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; > > > > You should return 1 here instead of -ENODEV. Also this check should > > better be done instead of > > > > if (!np) > > return 1; > > > > at the start of the function. > > Are you sure for the "1" value ? It seems a very bad error value. > And I found plenty of case where if (!np) return -Esomething and no example of return 1 This is not an error value. The semantic is: 0 everything ok, initialized from dt 1 device was not probed by dt -> fall back to board-file stuff <0 error that should abort probing Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |