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Tue, 26 Mar 2019 10:51:05 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at netline-mail3.netline.ch Received: from netline-mail3.netline.ch ([127.0.0.1]) by localhost (netline-mail3.netline.ch [127.0.0.1]) (amavisd-new, port 10024) with LMTP id UP0oX60E-7Qf; Tue, 26 Mar 2019 10:51:05 +0100 (CET) Received: from thor (116.245.63.188.dynamic.wline.res.cust.swisscom.ch [188.63.245.116]) by netline-mail3.netline.ch (Postfix) with ESMTPSA id 419B82A6053; Tue, 26 Mar 2019 10:51:05 +0100 (CET) Received: from [::1] by thor with esmtp (Exim 4.92) (envelope-from ) id 1h8ijY-0003Dy-M7; Tue, 26 Mar 2019 10:51:04 +0100 Subject: Re: [PATCH v2] gpu: radeon: fix a potential NULL-pointer dereference To: Kangjie Lu Cc: "David (ChunMing) Zhou" , David Airlie , linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Daniel Vetter , pakki001@umn.edu, Alex Deucher , =?UTF-8?Q?Christian_K=c3=b6nig?= References: <0fc81efe-186b-3207-e0d0-b0bb95626069@daenzer.net> <20190325210552.12797-1-kjlu@umn.edu> From: =?UTF-8?Q?Michel_D=c3=a4nzer?= Openpgp: preference=signencrypt Autocrypt: addr=michel@daenzer.net; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190325210552.12797-1-kjlu@umn.edu> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-03-25 10:05 p.m., Kangjie Lu wrote: > In case alloc_workqueue fails, the fix frees memory and > returns -ENOMEM to avoid potential NULL pointer dereference. > > Signed-off-by: Kangjie Lu > --- > v2: use radeon_crtc_destroy to properly clean up resources as > suggested by Michel Dänzer > > [...] > > @@ -671,13 +671,18 @@ static void radeon_crtc_init(struct drm_device *dev, int index) > > radeon_crtc = kzalloc(sizeof(struct radeon_crtc) + (RADEONFB_CONN_LIMIT * sizeof(struct drm_connector *)), GFP_KERNEL); > if (radeon_crtc == NULL) > - return; > + return -ENOMEM; > > drm_crtc_init(dev, &radeon_crtc->base, &radeon_crtc_funcs); > > drm_mode_crtc_set_gamma_size(&radeon_crtc->base, 256); > radeon_crtc->crtc_id = index; > radeon_crtc->flip_queue = alloc_workqueue("radeon-crtc", WQ_HIGHPRI, 0); > + if (!radeon_crtc->flip_queue) { > + DRM_ERROR("failed to allocate the flip queue\n"); > + radeon_crtc_destroy(&radeon_crtc->base); > + return -ENOMEM; > + } radeon_crtc_destroy currently unconditionally calls: destroy_workqueue(radeon_crtc->flip_queue); AFAICT destroy_workqueue will blow up if NULL is passed to it, so radeon_crtc_destroy needs to check for that. -- Earthling Michel Dänzer | https://www.amd.com Libre software enthusiast | Mesa and X developer