1 files changed, 4 insertions, 2 deletions
diff --git a/string.c b/string.c
index 589c80088e..4e30cb338a 100644
--- a/string.c
+++ b/string.c
@@ -1401,10 +1401,12 @@ rb_str_times(VALUE str, VALUE times)
 static VALUE
 rb_str_format_m(VALUE str, VALUE arg)
 {
-    volatile VALUE tmp = rb_check_array_type(arg);
+    VALUE tmp = rb_check_array_type(arg);
 
     if (!NIL_P(tmp)) {
-	return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
+	VALUE rv = rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
+	RB_GC_GUARD(tmp);
+	return rv;
     }
     return rb_str_format(1, &arg, str);
 }