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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 581BDC2D0E4 for ; Fri, 27 Nov 2020 15:52:08 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 013C121D7A for ; Fri, 27 Nov 2020 15:52:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 013C121D7A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 323516EE45; Fri, 27 Nov 2020 15:52:07 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 0325C6EE45 for ; Fri, 27 Nov 2020 15:52:03 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BA4D31516; Fri, 27 Nov 2020 07:52:02 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 173CB3F71F; Fri, 27 Nov 2020 07:52:01 -0800 (PST) Subject: Re: [PATCH] drm/komeda: Handle NULL pointer access code path in error case To: carsten.haitzler@foss.arm.com, dri-devel@lists.freedesktop.org References: <20201127110054.133686-1-carsten.haitzler@foss.arm.com> From: Steven Price Message-ID: Date: Fri, 27 Nov 2020 15:52:01 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201127110054.133686-1-carsten.haitzler@foss.arm.com> Content-Language: en-GB X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: liviu.dudau@arm.com, Carsten Haitzler Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 27/11/2020 11:00, carsten.haitzler@foss.arm.com wrote: > From: Carsten Haitzler > > komeda_component_get_old_state() technically can return a NULL > pointer. komeda_compiz_set_input() even warns when this happens, but > then proceeeds to use that NULL pointer tocompare memory content there > agains the new sate to see if it changed. In this case, it's better to > assume that the input changed as there is no old state to compare > against and thus assume the changes happen anyway. > > Signed-off-by: Carsten Haitzler > --- > drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c > index 8f32ae7c25d0..e8b1e15312d8 100644 > --- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c > @@ -707,7 +707,8 @@ komeda_compiz_set_input(struct komeda_compiz *compiz, > WARN_ON(!old_st); > > /* compare with old to check if this input has been changed */ > - if (memcmp(&(to_compiz_st(old_st)->cins[idx]), cin, sizeof(*cin))) > + if (!old_st || > + memcmp(&(to_compiz_st(old_st)->cins[idx]), cin, sizeof(*cin))) > c_st->changed_active_inputs |= BIT(idx); Even better, you can move the WARN_ON into the if: if (WARN_ON(!old_st) || ... Either way: Reviewed-by: Steven Price Steve > > komeda_component_add_input(c_st, &dflow->input, idx); > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel