All other accesses take this spinlock, so do this here, too.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Eric Anholt <eric@anholt.net>
 i915_gem_object_unbind(struct drm_gem_object *obj)
 {
        struct drm_device *dev = obj->dev;
+       drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_i915_gem_object *obj_priv = obj->driver_private;
        int ret = 0;
 
        }
 
        /* Remove ourselves from the LRU list if present. */
+       spin_lock(&dev_priv->mm.active_list_lock);
        if (!list_empty(&obj_priv->list))
                list_del_init(&obj_priv->list);
+       spin_unlock(&dev_priv->mm.active_list_lock);
 
        if (i915_gem_object_is_purgeable(obj_priv))
                i915_gem_object_truncate(obj);