From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E409C433E0 for ; Thu, 30 Jul 2020 08:59:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29A8720809 for ; Thu, 30 Jul 2020 08:59:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728693AbgG3I7S (ORCPT ); Thu, 30 Jul 2020 04:59:18 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:2957 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726287AbgG3I7S (ORCPT ); Thu, 30 Jul 2020 04:59:18 -0400 X-Originating-IP: 176.88.148.196 Received: from [192.168.1.3] (unknown [176.88.148.196]) (Authenticated sender: cengiz@kernel.wtf) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 9FA0C24000C; Thu, 30 Jul 2020 08:59:13 +0000 (UTC) From: Cengiz Can To: Dan Carpenter , Andy Shevchenko CC: "open list:STAGING SUBSYSTEM" , Andy Shevchenko , "Greg Kroah-Hartman" , Linux Kernel Mailing List , Sakari Ailus , Mauro Carvalho Chehab , Linux Media Mailing List Date: Thu, 30 Jul 2020 11:59:10 +0300 Message-ID: <1739ef25b30.2bfa.85c738e3968116fc5c0dc2de74002084@kernel.wtf> In-Reply-To: <20200730084545.GB1793@kadam> References: <20200729135636.9220-1-cengiz@kernel.wtf> <20200730084545.GB1793@kadam> User-Agent: AquaMail/1.25.2-1666 (build: 102500007) Subject: Re: [PATCH] staging: atomisp: move null check to earlier point MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="us-ascii" Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On July 30, 2020 11:48:06 Dan Carpenter wrote: > On Wed, Jul 29, 2020 at 06:13:44PM +0300, Andy Shevchenko wrote: >> On Wed, Jul 29, 2020 at 5:00 PM Cengiz Can wrote: >>> >>> `find_gmin_subdev` function that returns a pointer to `struct >>> gmin_subdev` can return NULL. >>> >>> In `gmin_v2p8_ctrl` there's a call to this function but the possibility >>> of a NULL was not checked before its being dereferenced. ie: >>> >>> ``` >>> /* Acquired here --------v */ >>> struct gmin_subdev *gs = find_gmin_subdev(subdev); >>> int ret; >>> int value; >>> >>> /* v------Dereferenced here */ >>> if (gs->v2p8_gpio >= 0) { >>> pr_info("atomisp_gmin_platform: 2.8v power on GPIO %d\n", >>> gs->v2p8_gpio); >>> ret = gpio_request(gs->v2p8_gpio, "camera_v2p8"); >>> if (!ret) >>> ret = gpio_direction_output(gs->v2p8_gpio, 0); >>> if (ret) >>> pr_err("V2P8 GPIO initialization failed\n"); >>> } >>> ``` >>> >>> I have moved the NULL check before deref point. >> >> "Move the NULL check..." >> See Submitting Patches documentation how to avoid "This patch", "I", "we", etc. Noted. Sorry. I'm not a native English speaker. >> > > I always feel like this is a pointless requirement. We're turning into > bureaucracts. > >> >>> diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> index 0df46a1af5f0..8e9c5016f299 100644 >>> --- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> +++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c >>> @@ -871,6 +871,11 @@ static int gmin_v2p8_ctrl(struct v4l2_subdev *subdev, >>> int on) >>> int ret; >>> int value; >>> >>> + if (!gs) { >>> + pr_err("Unable to find gmin subdevice\n"); >> >>> + return -EINVAL; >> >> And here is a change of semantics... > > Yeah. The change of semantics should be documented in the commit > message, but it's actually correct. I discussed this with Mauro earlier > but my bug reporting script didn't CC a mailing list and I didn't > catch it. Mauro suggested: > > 53 > Yet, it could make sense to have something like: > 54 > > 55 > if (WARN_ON(!gs)) > 56 > return -ENODEV; > 57 > > 58 > at the beginning of the functions that call find_gmin_subdev(). I will be updating v2 according to this. > > regards, > dan carpenter