diff --git a/ChangeLog b/ChangeLog
index 24867d3277..feecfbd4b7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue May 20 18:59:54 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* eval.c (rb_thread_save_context): prohibit rb_gc_force_recycle()
+	  on thread saved ruby_dyna_vars. [ruby-dev:20236]
+
 Tue May 20 17:39:15 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* object.c (init_copy): call initialize_copy at the end of copy
diff --git a/eval.c b/eval.c
index 3d8bb69a45..f7bc8d2c1f 100644
--- a/eval.c
+++ b/eval.c
@@ -7982,6 +7982,7 @@ rb_thread_save_context(th)
     th->stk_pos = (rb_gc_stack_start<pos)?rb_gc_stack_start
 				         :rb_gc_stack_start - len;
     if (len > th->stk_max) {
+	rb_gc();
 	REALLOC_N(th->stk_ptr, VALUE, len);
 	th->stk_max = len;
     }
@@ -7998,6 +7999,7 @@ rb_thread_save_context(th)
     th->wrapper = ruby_wrapper;
     th->cref = ruby_cref;
     th->dyna_vars = ruby_dyna_vars;
+    FL_SET(ruby_dyna_vars, DVAR_DONT_RECYCLE);
     th->block = ruby_block;
     th->flags &= THREAD_FLAGS_MASK;
     th->flags |= (rb_trap_immediate<<8) | scope_vmode;