diff --git a/ChangeLog b/ChangeLog
index e834f8ff92..a5c31582f7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Tue Nov 26 17:38:16 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* vm_trace.c: prohibit to specify normal events and internal events
+	  simultaneously.
+	  I will introduce special care for internal events later.
+
+	* ext/-test-/tracepoint/tracepoint.c: test this behavior.
+
+	* test/-ext-/tracepoint/test_tracepoint.rb: ditto.
+
 Tue Nov 26 16:30:31 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* file.c (rb_readlink): fix buffer overflow on a long symlink. since
diff --git a/NEWS b/NEWS
index d93a8ff346..1b27c83948 100644
--- a/NEWS
+++ b/NEWS
@@ -331,3 +331,5 @@ with all sufficient information, see the ChangeLog file.
   * RUBY_INTERNAL_EVENT_FREEOBJ
   * RUBY_INTERNAL_EVENT_GC_START
   * RUBY_INTERNAL_EVENT_GC_END
+  * Note that you *can not* specify "internal events" with normal events
+    (such as RUBY_EVENT_CALL, RUBY_EVENT_RETURN) simultaneously.
diff --git a/ext/-test-/tracepoint/tracepoint.c b/ext/-test-/tracepoint/tracepoint.c
index a974c2c611..ebe2996622 100644
--- a/ext/-test-/tracepoint/tracepoint.c
+++ b/ext/-test-/tracepoint/tracepoint.c
@@ -69,9 +69,18 @@ tracepoint_track_objspace_events(VALUE self)
     return result;
 }
 
+static VALUE
+tracepoint_specify_normal_and_internal_events(VALUE self)
+{
+    VALUE tpval = rb_tracepoint_new(0, RUBY_INTERNAL_EVENT_NEWOBJ | RUBY_EVENT_CALL, 0, 0);
+    rb_tracepoint_enable(tpval);
+    return Qnil; /* should not be reached */
+}
+
 void
 Init_tracepoint(void)
 {
     VALUE mBug = rb_define_module("Bug");
     rb_define_module_function(mBug, "tracepoint_track_objspace_events", tracepoint_track_objspace_events, 0);
+    rb_define_module_function(mBug, "tracepoint_specify_normal_and_internal_events", tracepoint_specify_normal_and_internal_events, 0);
 }
diff --git a/test/-ext-/tracepoint/test_tracepoint.rb b/test/-ext-/tracepoint/test_tracepoint.rb
index 967c65f368..27fcceceb5 100644
--- a/test/-ext-/tracepoint/test_tracepoint.rb
+++ b/test/-ext-/tracepoint/test_tracepoint.rb
@@ -50,4 +50,8 @@ class TestTracepointObj < Test::Unit::TestCase
     assert_operator gc_start_count, :>=, gc_end_count
     assert_operator stat2[:count] - stat1[:count] - 1, :<=, gc_end_count
   end
+
+  def test_tracepoint_specify_normal_and_internal_events
+    assert_raise(TypeError){ Bug.tracepoint_specify_normal_and_internal_events }
+  end
 end
diff --git a/vm_trace.c b/vm_trace.c
index 5930274be8..369bd7c4f1 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -105,7 +105,13 @@ thval2thread_t(VALUE thval)
 static rb_event_hook_t *
 alloc_event_hook(rb_event_hook_func_t func, rb_event_flag_t events, VALUE data, rb_event_hook_flag_t hook_flags)
 {
-    rb_event_hook_t *hook = ALLOC(rb_event_hook_t);
+    rb_event_hook_t *hook;
+
+    if ((events & RUBY_INTERNAL_EVENT_MASK) && (events & ~RUBY_INTERNAL_EVENT_MASK)) {
+	rb_raise(rb_eTypeError, "Can not specify normal event and internal event simultaneously.");
+    }
+
+    hook = ALLOC(rb_event_hook_t);
     hook->hook_flags = hook_flags;
     hook->events = events;
     hook->func = func;