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 S1753291AbbDGJZb (ORCPT <rfc822;w@1wt.eu>);
	Tue, 7 Apr 2015 05:25:31 -0400
Received: from aserp1040.oracle.com ([141.146.126.69]:41318 "EHLO
	aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751122AbbDGJZ0 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 7 Apr 2015 05:25:26 -0400
Date: Tue, 7 Apr 2015 11:27:08 +0200
From: Quentin Casasnovas <quentin.casasnovas@oracle.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@kernel.org>,
        Quentin Casasnovas <quentin.casasnovas@oracle.com>,
        X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Oleg Nesterov <oleg@redhat.com>, Andy Lutomirski <luto@amacapital.net>
Subject: Re: [PATCH] x86/alternatives: Fix ALTERNATIVE_2 padding generation
 properly
Message-ID: <20150407092708.GA25397@chrystal.uk.oracle.com>
References: <20150403173306.GG14902@chrystal.uk.oracle.com>
 <20150403174824.GL3418@pd.tnic>
 <20150403204217.GH14902@chrystal.uk.oracle.com>
 <20150404073454.GA21152@pd.tnic>
 <20150404083611.GA5922@chrystal.uk.oracle.com>
 <20150404092536.GB21152@pd.tnic>
 <20150404101155.GB5922@chrystal.uk.oracle.com>
 <20150404102922.GC21152@pd.tnic>
 <20150404133243.GD21152@pd.tnic>
 <20150404133443.GE21152@pd.tnic>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20150404133443.GE21152@pd.tnic>
User-Agent: Mutt/1.5.22 (2013-10-16)
X-Source-IP: userv0022.oracle.com [156.151.31.74]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Apr 04, 2015 at 03:34:43PM +0200, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
> 
> Quentin caught a corner case with the generation of instruction padding
> in the ALTERNATIVE_2 macro: if len(orig_insn) < len(alt1) < len(alt2),
> then not enough padding gets added and that is not good(tm) as we could
> overwrite the beginning of the next instruction.
> 

FWIW, this patch looks good to me (I have not tested it though).

Thanks!

Quentin