diff --git a/ractor.c b/ractor.c
index 55622999f0..3c87802970 100644
--- a/ractor.c
+++ b/ractor.c
@@ -460,6 +460,7 @@ ractor_basket_accept(struct rb_ractor_basket *b)
         break;
       case basket_type_copy_marshal:
         v = rb_marshal_load(b->v);
+        RB_GC_GUARD(b->v);
         break;
       case basket_type_exception:
         {