From 3324773f5696b322749fe9a02a5dc6099d4d2a72 Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby.or.jp>
Date: Fri, 2 Aug 2024 04:50:00 +0900
Subject: [PATCH] gc.c (mrb_gc_register): protect `obj` from GC during
 execution

Because `mrb_ary_new()` and `mrb_ary_push()` can cause GC; fix #6317
---
 src/gc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/gc.c b/src/gc.c
index 8c3b8d5b8..a54cf4a0b 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -418,11 +418,14 @@ mrb_gc_register(mrb_state *mrb, mrb_value obj)
 
   if (mrb_immediate_p(obj)) return;
   table = mrb_gv_get(mrb, GC_ROOT_SYM);
+  int ai = mrb_gc_arena_save(mrb);
+  mrb_gc_protect(mrb, obj);
   if (mrb_nil_p(table) || !mrb_array_p(table)) {
     table = mrb_ary_new(mrb);
     mrb_gv_set(mrb, GC_ROOT_SYM, table);
   }
   mrb_ary_push(mrb, table, obj);
+  mrb_gc_arena_restore(mrb, ai);
 }
 
 /* mrb_gc_unregister() removes the object from GC root. */