From patchwork Mon Mar 19 21:45:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 10302425 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 843C260386 for ; Thu, 22 Mar 2018 22:05:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F36528A0A for ; Thu, 22 Mar 2018 22:05:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 63FA928A0C; Thu, 22 Mar 2018 22:05:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 09C7D28A0A for ; Thu, 22 Mar 2018 22:05:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0E0856E070; Thu, 22 Mar 2018 22:05:18 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org X-Greylist: delayed 1382 seconds by postgrey-1.36 at gabe; Mon, 19 Mar 2018 22:08:31 UTC Received: from gateway23.websitewelcome.com (gateway23.websitewelcome.com [192.185.50.119]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6B0576E17C for ; Mon, 19 Mar 2018 22:08:31 +0000 (UTC) Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway23.websitewelcome.com (Postfix) with ESMTP id 422991874A for ; Mon, 19 Mar 2018 16:45:28 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id y2aueNEtNy2aLy2auepVI8; Mon, 19 Mar 2018 16:45:28 -0500 Received: from [189.145.36.34] (port=56610 helo=[192.168.1.67]) by gator4166.hostgator.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.89_1) (envelope-from ) id 1ey2as-001RJz-Mh; Mon, 19 Mar 2018 16:45:26 -0500 Subject: Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference To: Chris Wilson , Zhenyu Wang , Zhi Wang , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie References: <20180319193053.GA7016@embeddedgus> <152149190651.3594.5036347331521892974@mail.alporthouse.com> <8f70ff7b-9575-006b-2384-88899f24fda6@embeddedor.com> <152149459549.3594.15219721825785440264@mail.alporthouse.com> From: "Gustavo A. R. Silva" Message-ID: <276cc037-d768-1baa-aea5-da69c8d8a1e2@embeddedor.com> Date: Mon, 19 Mar 2018 16:45:24 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <152149459549.3594.15219721825785440264@mail.alporthouse.com> Content-Language: en-US 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 - lists.freedesktop.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.145.36.34 X-Source-L: No X-Exim-ID: 1ey2as-001RJz-Mh X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.1.67]) [189.145.36.34]:56610 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 10 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-Mailman-Approved-At: Thu, 22 Mar 2018 22:05:16 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP On 03/19/2018 04:23 PM, Chris Wilson wrote: > Quoting Gustavo A. R. Silva (2018-03-19 20:50:12) >> Hi Chris, >> >> On 03/19/2018 03:38 PM, Chris Wilson wrote: >>> Quoting Gustavo A. R. Silva (2018-03-19 19:30:53) >>>> _workload_ is being dereferenced before it is null checked, hence >>>> there is a potential null pointer dereference. >>>> >>>> Fix this by moving the pointer dereference after _workload_ has >>>> been null checked. >>> >>> The checks are misleading and not required. >> >> All of them? >> >> if (!workload || !reg_state || workload->ring_id != RCS) >> return; > > workload can not be NULL (dereference in caller), reg_state can not be > NULL (by construct from kmap()). > > It may be not an RCS ring through I got it. I'll send the following patch then: if (save) { Thanks --- Gustavo --- a/drivers/gpu/drm/i915/gvt/scheduler.c +++ b/drivers/gpu/drm/i915/gvt/scheduler.c @@ -74,7 +74,7 @@ static void sr_oa_regs(struct intel_vgpu_workload *workload, i915_mmio_reg_offset(EU_PERF_CNTL6), }; - if (!workload || !reg_state || workload->ring_id != RCS) + if(workload->ring_id != RCS) return;