From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: [PATCH] drm/fb-helper: Fix potential NULL pointer dereference Date: Tue, 5 Dec 2017 11:46:28 -0600 Message-ID: <20171205174628.GA31189@embeddedor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org 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" List-Id: dri-devel@lists.freedesktop.org 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