Re: [PATCH 04/17] drm: add object property type

On Mon, May 26, 2014 at 10:29:47AM +0200, Daniel Vetter wrote:

On Sat, May 24, 2014 at 02:30:13PM -0400, Rob Clark wrote:

...

• } else if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) {

• /* a zero value for an object property translates to null: */
  

• if (value == 0)
  

• 	return true;
  

• return drm_property_get_obj(property, value) != NULL;
  

Ok, so this usage is indeed safe for framebuffers since you only compare the pointer against NULL. But you can't ever access this pointer since it might disappear any time after you've dropped the idr lock. I think what you actually want here is a new interface drm_mode_object_exists which just returns a bool.

That won't expose any risky things to callers and we can still keep the restriction that calling drm_mode_object_get for framebuffers is a BUG.

s/object_get/object_find/ I've meant ofc. -Daniel