drm/fb-helper: Do the 'max_conn_count' zero check

Since we cannot make sure the 'max_conn_count' will always be none
zero from the users, and then if max_conn_count equals to zero, the
kcalloc() will return ZERO_SIZE_PTR, which equals to ((void *)16).

So this patch fix this with just doing the 'max_conn_count' zero check
in the front of drm_fb_helper_init().

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
CC: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index e5208e0..89382dc 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -516,6 +516,9 @@ int drm_fb_helper_init(struct drm_device *dev,
        struct drm_crtc *crtc;
        int i;
 
+       if (!max_conn_count)
+               return -EINVAL;
+
        fb_helper->dev = dev;
 
        INIT_LIST_HEAD(&fb_helper->kernel_fb_list);