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 S1030459AbcBZSRw (ORCPT <rfc822;w@1wt.eu>);
	Fri, 26 Feb 2016 13:17:52 -0500
Received: from mail.skyhub.de ([78.46.96.112]:33135 "EHLO mail.skyhub.de"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1030395AbcBZSRt (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Fri, 26 Feb 2016 13:17:49 -0500
Date: Fri, 26 Feb 2016 19:17:43 +0100
From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>, Jiri Slaby <jslaby@suse.cz>,
        Greg KH <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        stable <stable@vger.kernel.org>, lwn@lwn.net,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: BUG: unable to handle kernel paging request from pty_write [was:
 Linux 4.4.2]
Message-ID: <20160226181743.GA12735@pd.tnic>
References: <CA+55aFxXAiJe=NPuxJ3vQFn6T12_nVV2+Yz4yChYbavtB+1caw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CA+55aFxXAiJe=NPuxJ3vQFn6T12_nVV2+Yz4yChYbavtB+1caw@mail.gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Feb 26, 2016 at 10:05:26AM -0800, Linus Torvalds wrote:
> Of course, if Jiri isn't actually running this on an AMD CPU, that
> theory flies right out the window. But we do have a reported oops on
> the security list that looks totally different in the big picture, but
> shares the exact same "corrupted stack pointer register state
> resulting in crazy instruction pointer, resulting in NX fault"
> behavior in the end.
> 
> In the other case, microcode patchlevel 0x0600081c was fine, and
> 0x06000832 is the one exhibiting the corruption problem.
> 
> I've contacted Robert Święcki (who found the microcode problem) in
> case he wants to weigh in in this thread.. He was talking to some AMD
> people, but I don't know the exactly who.

It most likely is that problem. If Jiri is using the IBS machines -
and from quick look at http://labs.suse.cz/jslaby/bug-968218/gdb_log,
it looks like he is, then they are exactly those boxes with a b0rked
microcode patch. AMD is working on a fix.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.