diff --git a/ChangeLog b/ChangeLog
index 7f9603f859..ebc94669a0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Oct  9 23:50:21 2003  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (rb_thread_start_0): prevent thread from GC.
+	  [ruby-dev:21572]
+
 Thu Oct  9 19:11:44 2003  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* eval.c (rb_thread_start_0): non-volatile should be restored from
diff --git a/eval.c b/eval.c
index 033134cb38..8fb1ac6a56 100644
--- a/eval.c
+++ b/eval.c
@@ -9385,6 +9385,7 @@ rb_thread_start_0(fn, arg, th)
     rb_thread_t th;
 {
     volatile rb_thread_t th_save = th;
+    volatile VALUE thread = th->thread;
     struct BLOCK *volatile saved_block = 0, *block;
     enum thread_status status;
     int state;
@@ -9408,7 +9409,7 @@ rb_thread_start_0(fn, arg, th)
 #endif
 
     if (THREAD_SAVE_CONTEXT(curr_thread)) {
-	return th_save->thread;
+	return thread;
     }
 
     if (ruby_block) {		/* should nail down higher blocks */