Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752487AbbKLI03 (ORCPT ); Thu, 12 Nov 2015 03:26:29 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:32790 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963AbbKLI01 (ORCPT ); Thu, 12 Nov 2015 03:26:27 -0500 Date: Thu, 12 Nov 2015 09:26:17 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Frans Klaver Cc: LABBE Corentin , baruch@tkos.co.il, Brian Norris , David Woodhouse , Krzysztof =?utf-8?Q?Koz=C5=82owski?= , Luis de Bethencourt , 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: <20151112082617.GE24008@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: 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 Content-Length: 1305 Lines: 38 On Thu, Nov 12, 2015 at 09:03:11AM +0100, Frans Klaver wrote: > 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? Yes, you're missing something. The driver would probe for a dt snippet like: mxc_nand { compatible = "foobar"; } In this case dev->of_node is non-NULL but of_match_device(mxcnd_dt_ids, dev) is. (I didn't actually test this, so there is a chance I'm wrong here. And if not I wonder if it is sensible at all to match the device name on driver name for of-created platform devices.) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/