diff --git a/ChangeLog b/ChangeLog
index 744f7a36fb..3e27c12dad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Sun Jun 15 18:17:03 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_core.h (rb_vm_t), vm.c (rb_vm_mark): moved preallocated special
+	  exceptions.
+
+	* eval.c (Init_eval), gc.c (Init_GC), proc.c (Init_Proc): freeze
+	  preallocated special exceptions.
+
+	* eval.c (rb_longjmp): duplicate the thrown exception to set backtrace
+	  if it was frozen.
+
+	* gc.c (rb_memerror): raise nomem_error without backtrace if failed to
+	  make backtrace.
+
 Sat Jun 14 22:52:35 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/stringio/stringio.c (strio_sysread): should not raise at empty
diff --git a/eval.c b/eval.c
index bb1e43bb73..f6424372f7 100644
--- a/eval.c
+++ b/eval.c
@@ -20,9 +20,8 @@ NORETURN(void rb_raise_jump(VALUE));
 ID rb_frame_callee(void);
 VALUE rb_eLocalJumpError;
 VALUE rb_eSysStackError;
-VALUE sysstack_error;
 
-static VALUE exception_error;
+#define exception_error GET_VM()->special_exceptions[ruby_error_reenter]
 
 #include "eval_error.c"
 #include "eval_safe.c"
@@ -372,6 +371,9 @@ rb_longjmp(int tag, VALUE mesg)
 	at = get_backtrace(mesg);
 	if (NIL_P(at)) {
 	    at = rb_make_backtrace();
+	    if (OBJ_FROZEN(mesg)) {
+		mesg = rb_obj_dup(mesg);
+	    }
 	    set_backtrace(mesg, at);
 	}
     }
@@ -1198,7 +1200,8 @@ Init_eval(void)
 
     exception_error = rb_exc_new2(rb_eFatal, "exception reentered");
     rb_ivar_set(exception_error, idThrowState, INT2FIX(TAG_FATAL));
-    rb_register_mark_object(exception_error);
+    OBJ_TAINT(exception_error);
+    OBJ_FREEZE(exception_error);
 }
 
 
diff --git a/gc.c b/gc.c
index af88862393..20af24f82d 100644
--- a/gc.c
+++ b/gc.c
@@ -84,7 +84,7 @@ void *alloca ();
 #endif
 #endif
 
-static VALUE nomem_error;
+#define nomem_error GET_VM()->special_exceptions[ruby_error_nomemory]
 
 #define MARK_STACK_MAX 1024
 
@@ -265,6 +265,11 @@ rb_memerror(void)
 	fprintf(stderr, "[FATAL] failed to allocate memory\n");
 	exit(EXIT_FAILURE);
     }
+    if (rb_thread_raised_p(th, RAISED_NOMEMORY)) {
+	rb_thread_raised_clear(th);
+	GET_THREAD()->errinfo = nomem_error;
+	JUMP_TAG(TAG_RAISE);
+    }
     rb_thread_raised_set(th, RAISED_NOMEMORY);
     rb_exc_raise(nomem_error);
 }
@@ -2394,8 +2399,9 @@ Init_GC(void)
 
     rb_define_module_function(rb_mObSpace, "_id2ref", id2ref, 1);
 
-    rb_global_variable(&nomem_error);
     nomem_error = rb_exc_new2(rb_eNoMemError, "failed to allocate memory");
+    OBJ_TAINT(nomem_error);
+    OBJ_FREEZE(nomem_error);
 
     rb_define_method(rb_mKernel, "hash", rb_obj_id, 0);
     rb_define_method(rb_mKernel, "__id__", rb_obj_id, 0);
diff --git a/proc.c b/proc.c
index 3234c0e03c..eecff7ae12 100644
--- a/proc.c
+++ b/proc.c
@@ -1756,7 +1756,7 @@ Init_Proc(void)
     rb_eSysStackError = rb_define_class("SystemStackError", rb_eException);
     sysstack_error = rb_exc_new2(rb_eSysStackError, "stack level too deep");
     OBJ_TAINT(sysstack_error);
-    rb_register_mark_object(sysstack_error);
+    OBJ_FREEZE(sysstack_error);
 
     /* utility functions */
     rb_define_global_function("proc", rb_block_proc, 0);
diff --git a/version.h b/version.h
index 497179ad96..43eea68393 100644
--- a/version.h
+++ b/version.h
@@ -1,7 +1,7 @@
 #define RUBY_VERSION "1.9.0"
-#define RUBY_RELEASE_DATE "2008-06-14"
+#define RUBY_RELEASE_DATE "2008-06-15"
 #define RUBY_VERSION_CODE 190
-#define RUBY_RELEASE_CODE 20080614
+#define RUBY_RELEASE_CODE 20080615
 #define RUBY_PATCHLEVEL 0
 
 #define RUBY_VERSION_MAJOR 1
@@ -9,7 +9,7 @@
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_YEAR 2008
 #define RUBY_RELEASE_MONTH 6
-#define RUBY_RELEASE_DAY 14
+#define RUBY_RELEASE_DAY 15
 
 #ifdef RUBY_EXTERN
 RUBY_EXTERN const char ruby_version[];
diff --git a/vm.c b/vm.c
index 64fbe2d1c9..bb1ba4cb59 100644
--- a/vm.c
+++ b/vm.c
@@ -1393,6 +1393,7 @@ rb_vm_mark(void *ptr)
 	RUBY_MARK_UNLESS_NULL(vm->load_path);
 	RUBY_MARK_UNLESS_NULL(vm->loaded_features);
 	RUBY_MARK_UNLESS_NULL(vm->top_self);
+	rb_gc_mark_locations(vm->special_exceptions, vm->special_exceptions + ruby_special_error_count - 1);
 
 	if (vm->loading_table) {
 	    rb_mark_tbl(vm->loading_table);
diff --git a/vm_core.h b/vm_core.h
index b001491f00..18d1771035 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -281,6 +281,13 @@ struct rb_iseq_struct {
     struct iseq_compile_data *compile_data;
 };
 
+enum ruby_special_exceptions {
+    ruby_error_reenter,
+    ruby_error_nomemory,
+    ruby_error_sysstack,
+    ruby_special_error_count
+};
+
 typedef struct rb_iseq_struct rb_iseq_t;
 
 #define GetVMPtr(obj, ptr) \
@@ -307,6 +314,8 @@ struct rb_vm_struct
     /* object management */
     VALUE mark_object_ary;
 
+    VALUE special_exceptions[ruby_special_error_count];
+
     /* load */
     VALUE top_self;
     VALUE load_path;
@@ -648,7 +657,7 @@ VALUE vm_make_env_object(rb_thread_t *th, rb_control_frame_t *cfp);
 
 NOINLINE(void rb_gc_save_machine_context(rb_thread_t *));
 
-RUBY_EXTERN VALUE sysstack_error;
+#define sysstack_error GET_VM()->special_exceptions[ruby_error_sysstack]
 
 /* for thread */