diff --git a/ChangeLog b/ChangeLog
index f2125783ab..48d5e9cbf7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Nov 26 15:33:02 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* bignum.c (big_div_struct): added volatile to 'stop' member.
+	  Otherwise, "if (bds->stop)" check in bigdivrem1 don't read
+	  memory and ignore interrupt.
+	* bignum.c (bigdivrem, rb_big_stop): ditto.
+
 Mon Nov 26 12:11:09 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* win32/Makefile.sub (DLNOBJ): missing in r37821.
diff --git a/bignum.c b/bignum.c
index 97be53faf1..8939282ebf 100644
--- a/bignum.c
+++ b/bignum.c
@@ -2657,7 +2657,7 @@ rb_big_mul(VALUE x, VALUE y)
 struct big_div_struct {
     long nx, ny;
     BDIGIT *yds, *zds;
-    VALUE stop;
+    volatile VALUE stop;
 };
 
 static void *
@@ -2708,8 +2708,8 @@ bigdivrem1(void *ptr)
 static void
 rb_big_stop(void *ptr)
 {
-    VALUE *stop = (VALUE*)ptr;
-    *stop = Qtrue;
+    struct big_div_struct *bds = ptr;
+    bds->stop = Qtrue;
 }
 
 static VALUE
@@ -2794,7 +2794,7 @@ bigdivrem(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
     bds.yds = yds;
     bds.stop = Qfalse;
     if (nx > 10000 || ny > 10000) {
-	rb_thread_call_without_gvl(bigdivrem1, &bds, rb_big_stop, &bds.stop);
+	rb_thread_call_without_gvl(bigdivrem1, &bds, rb_big_stop, &bds);
     }
     else {
 	bigdivrem1(&bds);