diff --git a/vm.c b/vm.c
index 4b4b440025..40041302b5 100644
--- a/vm.c
+++ b/vm.c
@@ -2398,7 +2398,9 @@ rb_execution_context_mark(const rb_execution_context_t *ec)
     }
 
     /* mark machine stack */
-    if (ec->machine.stack_start && ec->machine.stack_end) {
+    if (ec->machine.stack_start && ec->machine.stack_end &&
+	ec != GET_EC() /* marked for current ec at the first stage of marking */
+	) {
 	rb_gc_mark_machine_stack(ec);
 	rb_gc_mark_locations((VALUE *)&ec->machine.regs,
 			     (VALUE *)(&ec->machine.regs) +