diff --git a/bsd-core/drm_bufs.c b/bsd-core/drm_bufs.c
index 1f83ba38..88445a4d 100644
--- a/bsd-core/drm_bufs.c
+++ b/bsd-core/drm_bufs.c
@@ -213,7 +213,7 @@ int drm_addmap(struct drm_device * dev, unsigned long offset,
 			DRM_LOCK();
 			return EINVAL;
 		}
-		map->offset = map->offset + dev->sg->handle;
+		map->offset += dev->sg->handle;
 		break;
 	case _DRM_CONSISTENT:
 		/* Unfortunately, we don't get any alignment specification from