From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S933498AbcDSRsK (ORCPT <rfc822;w@1wt.eu>);
	Tue, 19 Apr 2016 13:48:10 -0400
Received: from mail-pf0-f169.google.com ([209.85.192.169]:33729 "EHLO
	mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S933138AbcDSRsJ (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 19 Apr 2016 13:48:09 -0400
To: aryabinin@virtuozzo.com
Cc: "linux-kernel@vger.kernel.org >> LKML" <linux-kernel@vger.kernel.org>
From: "Shi, Yang" <yang.shi@linaro.org>
Subject: KASAN can't change FRAME_WARN
Message-ID: <57166F56.8010401@linaro.org>
Date: Tue, 19 Apr 2016 10:48:06 -0700
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.7.2
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Andrey,

When I enable KASAN for 4.5 and 4.6 (I didn't try with older versions), 
I got FRAME_WARN warning for frame size exceeds 2048 bytes.

Then I found the kconfig looks like:

range 0 8192
default 0 if KASAN
default 1024 if !64BIT
default 2048 if 64BIT

In my understanding, FRAME_WARN should be 0 once KASAN is enabled, but 
it is still 2048. I tried a couple of fixes, i.e.

default 0 if KASAN
default 1024 if (!KASAN && !64BIT)
default 2048 if (!KASAN && 64BIT)

But, nothing works, so I have to add "depends on !KASAN" to disable 
FRAME_WARN completely, but it causes the kernel image size increased.

Any hint is appreciated.

Thanks,
Yang