Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752628AbdLERqe (ORCPT ); Tue, 5 Dec 2017 12:46:34 -0500 Received: from gateway22.websitewelcome.com ([192.185.47.109]:37133 "EHLO gateway22.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752212AbdLERqb (ORCPT ); Tue, 5 Dec 2017 12:46:31 -0500 Date: Tue, 5 Dec 2017 11:46:28 -0600 From: "Gustavo A. R. Silva" To: Daniel Vetter , Jani Nikula , Gustavo Padovan , Sean Paul , David Airlie Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] drm/fb-helper: Fix potential NULL pointer dereference Message-ID: <20171205174628.GA31189@embeddedor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) 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: 189.155.98.198 X-Source-L: No X-Exim-ID: 1eMHIb-002k66-Mu X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.155.98.198]:44308 X-Source-Auth: garsilva@embeddedor.com X-Email-Count: 12 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1307 Lines: 38 fb_helper is being dereferenced before it is null checked, hence there is a potential null pointer dereference. Fix this by moving the pointer dereference after fb_helper has been null checked. This issue was detected with the help of Coccinelle. Fixes: c777990fb45b ("drm/fb-helper: Handle function NULL argument") Signed-off-by: Gustavo A. R. Silva --- drivers/gpu/drm/drm_fb_helper.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 6654f2f..04a3a5c 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -178,7 +178,7 @@ EXPORT_SYMBOL(drm_fb_helper_add_one_connector); */ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) { - struct drm_device *dev = fb_helper->dev; + struct drm_device *dev; struct drm_connector *connector; struct drm_connector_list_iter conn_iter; int i, ret = 0; @@ -186,6 +186,8 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) if (!drm_fbdev_emulation || !fb_helper) return 0; + dev = fb_helper->dev; + mutex_lock(&fb_helper->lock); drm_connector_list_iter_begin(dev, &conn_iter); drm_for_each_connector_iter(connector, &conn_iter) { -- 2.7.4