diff --git a/safe.c b/safe.c
index d790156c03..1f954ec8b9 100644
--- a/safe.c
+++ b/safe.c
@@ -90,8 +90,8 @@ rb_secure(int level)
     if (level <= rb_safe_level()) {
 	ID caller_name = rb_frame_callee();
 	if (caller_name) {
-	    rb_raise(rb_eSecurityError, "Insecure operation `%s' at level %d",
-		     rb_id2name(caller_name), rb_safe_level());
+	    rb_raise(rb_eSecurityError, "Insecure operation `%"PRIsVALUE"' at level %d",
+		     rb_id2str(caller_name), rb_safe_level());
 	}
 	else {
 	    rb_raise(rb_eSecurityError, "Insecure operation at level %d",
diff --git a/test/ruby/test_dir.rb b/test/ruby/test_dir.rb
index ee1210cc37..03c62da547 100644
--- a/test/ruby/test_dir.rb
+++ b/test/ruby/test_dir.rb
@@ -304,4 +304,21 @@ class TestDir < Test::Unit::TestCase
       end
     }
   end
+
+  def test_insecure_chdir
+    assert_raise(SecurityError) do
+      proc do
+        $SAFE=3
+        Dir.chdir("/")
+      end.call
+    end
+    m = "\u{79fb 52d5}"
+    d = Class.new(Dir) {singleton_class.class_eval {alias_method m, :chdir}}
+    assert_raise_with_message(SecurityError, /#{m}/) do
+      proc do
+        $SAFE=3
+        d.__send__(m, "/")
+      end.call
+    end
+  end
 end