Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754279AbdGJTZB (ORCPT ); Mon, 10 Jul 2017 15:25:01 -0400 Received: from gateway20.websitewelcome.com ([192.185.47.18]:17295 "EHLO gateway20.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754176AbdGJTZA (ORCPT ); Mon, 10 Jul 2017 15:25:00 -0400 Date: Mon, 10 Jul 2017 14:24:55 -0500 Message-ID: <20170710142455.Horde.1omqcjm0Viv_2slRPRXktZa@gator4166.hostgator.com> From: "Gustavo A. R. Silva" To: Dmitry Torokhov Cc: Thierry Reding , Jon Hunter , Rakesh Iyer , Laxman Dewangan , linux-input@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] input: tegra-kbc: add NULL check on of_match_device() return value References: <20170707062758.GA17584@embeddedgus> <20170707093041.GC15652@ulmo.fritz.box> <20170710174255.GB23984@dtor-ws> In-Reply-To: <20170710174255.GB23984@dtor-ws> User-Agent: Horde Application Framework 5 Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes MIME-Version: 1.0 Content-Disposition: inline X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 108.167.133.22 X-Exim-ID: 1dUeIi-002wZ2-SA X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: gator4166.hostgator.com [108.167.133.22]:34975 X-Source-Auth: garsilva@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1685 Lines: 55 Hi all, Quoting Dmitry Torokhov : > On Fri, Jul 07, 2017 at 11:30:41AM +0200, Thierry Reding wrote: >> On Fri, Jul 07, 2017 at 08:42:32AM +0100, Jon Hunter wrote: >> > >> > On 07/07/17 07:27, Gustavo A. R. Silva wrote: >> > > Check return value from call to of_match_device() >> > > in order to prevent a NULL pointer dereference. >> > > >> > > In case of NULL print error message and return -ENODEV >> > > >> > > Signed-off-by: Gustavo A. R. Silva >> > > --- >> > > drivers/input/keyboard/tegra-kbc.c | 4 ++++ >> > > 1 file changed, 4 insertions(+) >> > > >> > > diff --git a/drivers/input/keyboard/tegra-kbc.c >> b/drivers/input/keyboard/tegra-kbc.c >> > > index 0c07e10..742c5ac 100644 >> > > --- a/drivers/input/keyboard/tegra-kbc.c >> > > +++ b/drivers/input/keyboard/tegra-kbc.c >> > > @@ -617,6 +617,10 @@ static int tegra_kbc_probe(struct >> platform_device *pdev) >> > > const struct of_device_id *match; >> > > >> > > match = of_match_device(tegra_kbc_of_match, &pdev->dev); >> > > + if (!match) { >> > > + dev_err(&pdev->dev, "failed to match device\n"); >> > > + return -ENODEV; >> > > + } >> > >> > Given that Tegra always uses device-tree, I believe that this cannot >> > happen and so this additional check is not needed. >> >> I think you can make it happen if you manually create the platform >> device with a name matching that of the driver. But you really shouldn't >> be doing that, so might as well let it crash and burn so that people >> realize their mistake early. >> >> Errors are easily overlooked, crashes are not. > > Agree. > I get it. Thanks for clarifying. -- Gustavo A. R. Silva