diff --git a/src/loader/loader_dri3_helper.c b/src/loader/loader_dri3_helper.c
index ccf8d1795e7..6c4b704ae5b 100644
--- a/src/loader/loader_dri3_helper.c
+++ b/src/loader/loader_dri3_helper.c
@@ -2017,6 +2017,9 @@ dri3_free_buffers(__DRIdrawable *driDrawable,
       first_id = LOADER_DRI3_FRONT_ID;
       /* Don't free a fake front holding new backbuffer content. */
       n_id = (draw->cur_blit_source == LOADER_DRI3_FRONT_ID) ? 0 : 1;
+      break;
+   default:
+      unreachable("unhandled buffer_type");
    }
 
    for (buf_id = first_id; buf_id < first_id + n_id; buf_id++) {