diff --git a/src/gallium/auxiliary/renderonly/renderonly.c b/src/gallium/auxiliary/renderonly/renderonly.c
index fc09f16a167..8ec58e638a6 100644
--- a/src/gallium/auxiliary/renderonly/renderonly.c
+++ b/src/gallium/auxiliary/renderonly/renderonly.c
@@ -43,6 +43,7 @@ renderonly_scanout_destroy(struct renderonly_scanout *scanout,
 {
    struct drm_mode_destroy_dumb destroy_dumb = {0};
 
+   assert(p_atomic_read(&scanout->refcnt) > 0);
    if (p_atomic_dec_return(&scanout->refcnt))
       return;