diff --git a/ddl/index.go b/ddl/index.go
index 78954270870bd..9bed641c75b91 100644
--- a/ddl/index.go
+++ b/ddl/index.go
@@ -690,7 +690,7 @@ func (w *addIndexWorker) run(d *ddlCtx) {
 
 		log.Debug("[ddl-reorg] got backfill index task:#v", task)
 		// gofail: var mockAddIndexErr bool
-		//if mockAddIndexErr && !gofailMockAddindexErrOnceGuard && w.id == 0 {
+		//if w.id == 0 && mockAddIndexErr && !gofailMockAddindexErrOnceGuard {
 		//	gofailMockAddindexErrOnceGuard = true
 		//	result := &addIndexResult{addedCount: 0, nextHandle: 0, err: errors.Errorf("mock add index error")}
 		//	w.resultCh <- result