gistfile1.txt

diff --git a/src/6model/serialization.c b/src/6model/serialization.c
index 2ca9df617..e61c4f274 100644
--- a/src/6model/serialization.c
+++ b/src/6model/serialization.c
@@ -2714,11 +2714,17 @@ static void deserialize_stable(MVMThreadContext *tc, MVMSerializationReader *rea
     deserialize_method_cache_lazy(tc, st, reader);
 
     /* Type check cache. */
-    st->type_check_cache_length = MVM_serialization_read_int(tc, reader);
-    if (st->type_check_cache_length > 0) {
-        st->type_check_cache = (MVMObject **)MVM_malloc(st->type_check_cache_length * sizeof(MVMObject *));
-        for (i = 0; i < st->type_check_cache_length; i++)
+    MVMuint16 type_check_cache_length = MVM_serialization_read_int(tc, reader);
+    st->type_check_cache_length = 0;
+    if (type_check_cache_length > 0) {
+        st->type_check_cache = (MVMObject **)MVM_malloc(type_check_cache_length * sizeof(MVMObject *));
+        for (i = 0; i < type_check_cache_length; i++) {
             MVM_ASSIGN_REF(tc, &(st->header), st->type_check_cache[i], MVM_serialization_read_ref(tc, reader));
+            /* deserializing an object may trigger GC, so make sure a gc_mark
+             * of the half-deserialized stable only sees the already
+             * deserialized objects */
+            st->type_check_cache_length = i + 1;
+        }
     }
 
     /* Mode flags. */