From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zwn6f-00037T-An for linux-mtd@lists.infradead.org; Thu, 12 Nov 2015 08:19:46 +0000 Date: Thu, 12 Nov 2015 09:19:09 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: LABBE Corentin Cc: 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: <20151112081909.GD24008@pengutronix.de> References: <1447314423-31225-1-git-send-email-clabbe.montjoie@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1447314423-31225-1-git-send-email-clabbe.montjoie@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. I really wonder there is no helper function like: #define of_sensible_name(dev) of_match_device(dev->driver->of_match_table, dev) Best regards Uwe > host->devtype_data = of_id->data; > > return 0; > -- > 2.4.10 > > -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |