From: Gustavo A. R. Silva Date: Tue, 5 Dec 2017 17:46:28 +0000 (-0600) Subject: drm/fb-helper: Fix potential NULL pointer dereference X-Git-Tag: for-linus-20180210~4^2~28^2~1 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=89f3f35620c7f244880485de11079cb4d98ed604;p=linux-2.6-block.git drm/fb-helper: Fix potential NULL pointer dereference 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 Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20171205174628.GA31189@embeddedor.com --- diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 6654f2f87775..04a3a5ce370a 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) {