diff --git a/ChangeLog b/ChangeLog
index 760be6e117..0b0039cdd9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Aug 16 06:39:19 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (get_backtrace): check the result more.
+	  [ruby-dev:31261] [ruby-bugs-12398]
+
 Thu Aug 16 06:32:25 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* bignum.c (rb_big_lshift, rb_big_rshift): separated functions
diff --git a/error.c b/error.c
index 93093e0e0f..6ebc927853 100644
--- a/error.c
+++ b/error.c
@@ -488,14 +488,14 @@ static VALUE
 exc_backtrace(exc)
     VALUE exc;
 {
-    ID bt = rb_intern("bt");
+    static ID bt;
 
-    if (!rb_ivar_defined(exc, bt)) return Qnil;
-    return rb_ivar_get(exc, bt);
+    if (!bt) bt = rb_intern("bt");
+    return rb_attr_get(exc, bt);
 }
 
-static VALUE
-check_backtrace(bt)
+VALUE
+rb_check_backtrace(bt)
     VALUE bt;
 {
     long i;
@@ -532,7 +532,7 @@ exc_set_backtrace(exc, bt)
     VALUE exc;
     VALUE bt;
 {
-    return rb_iv_set(exc, "bt", check_backtrace(bt));
+    return rb_iv_set(exc, "bt", rb_check_backtrace(bt));
 }
 
 /*
diff --git a/eval.c b/eval.c
index 520eb987af..00142515e3 100644
--- a/eval.c
+++ b/eval.c
@@ -1200,6 +1200,8 @@ error_pos()
     }
 }
 
+VALUE rb_check_backtrace(VALUE);
+
 static VALUE
 get_backtrace(info)
     VALUE info;
@@ -1207,7 +1209,7 @@ get_backtrace(info)
     if (NIL_P(info)) return Qnil;
     info = rb_funcall(info, rb_intern("backtrace"), 0);
     if (NIL_P(info)) return Qnil;
-    return rb_check_array_type(info);
+    return rb_check_backtrace(info);
 }
 
 static void
diff --git a/version.h b/version.h
index 462fb12c5a..e62fc686a9 100644
--- a/version.h
+++ b/version.h
@@ -2,7 +2,7 @@
 #define RUBY_RELEASE_DATE "2007-08-16"
 #define RUBY_VERSION_CODE 185
 #define RUBY_RELEASE_CODE 20070816
-#define RUBY_PATCHLEVEL 80
+#define RUBY_PATCHLEVEL 81
 
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 8