diff --git a/executor/adapter.go b/executor/adapter.go
index ed2c0566e0f81..444c358f96c97 100644
--- a/executor/adapter.go
+++ b/executor/adapter.go
@@ -1611,8 +1611,8 @@ func (a *ExecStmt) LogSlowQuery(txnTS uint64, succ bool, hasMoreResults bool) {
 }
 
 func extractMsgFromSQLWarn(SQLWarn *stmtctx.SQLWarn) string {
-	// Currently, this function is only used in extractMsgFromSQLWarn().
-	// extractMsgFromSQLWarn() can make sure SQLWarn is not nil so no need to add a nil check here.
+	// Currently, this function is only used in collectWarningsForSlowLog.
+	// collectWarningsForSlowLog can make sure SQLWarn is not nil so no need to add a nil check here.
 	warn := errors.Cause(SQLWarn.Err)
 	if x, ok := warn.(*terror.Error); ok && x != nil {
 		sqlErr := terror.ToSQLError(x)