diff --git a/ChangeLog b/ChangeLog
index 8c25b92c94..a20eb74a86 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Sat Feb  5 00:59:54 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* vm_core.h (GetThreadPtr): use TypedData_Get_Struct() instead
+	  CoreDataFromValue() because we need type check. Otherwise,
+	  type mismatch can cause segmentation fault crash.
+	  [ruby-core:35086] [Ruby 1.9-Bug#4367]
+
+	* vm.c (thread_data_type): remove static.
+
 Fri Feb  4 19:14:27 2011  Tanaka Akira  <akr@fsij.org>
 
 	* enc/trans/utf8_mac.trans: parenthesize macro arguments.
diff --git a/vm.c b/vm.c
index 130ca64160..1dbf2ecabb 100644
--- a/vm.c
+++ b/vm.c
@@ -1756,7 +1756,7 @@ thread_memsize(const void *ptr)
     }
 }
 
-static const rb_data_type_t thread_data_type = {
+const rb_data_type_t thread_data_type = {
     "VM/thread",
     {
 	rb_thread_mark,
diff --git a/vm_core.h b/vm_core.h
index a0b60b5074..f20dfb02f3 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -347,8 +347,10 @@ typedef struct rb_block_struct {
     VALUE proc;
 } rb_block_t;
 
+extern const rb_data_type_t thread_data_type;
+
 #define GetThreadPtr(obj, ptr) \
-  GetCoreDataFromValue((obj), rb_thread_t, (ptr))
+    TypedData_Get_Struct((obj), rb_thread_t, &thread_data_type, (ptr))
 
 enum rb_thread_status {
     THREAD_TO_KILL,