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 S941378AbcJSOTV (ORCPT <rfc822;w@1wt.eu>);
        Wed, 19 Oct 2016 10:19:21 -0400
Received: from mail-lf0-f67.google.com ([209.85.215.67]:35300 "EHLO
        mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S941346AbcJSOTS (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 19 Oct 2016 10:19:18 -0400
Date: Wed, 19 Oct 2016 15:20:58 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        "H . Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Brian Gerst <brgerst@gmail.com>, Peter Zijlstra <peterz@infradead.org>,
        Nilay Vaish <nilayvaish@gmail.com>
Subject: Re: [PATCH v2 0/9] x86/entry/head: standardize the end of the stack
Message-ID: <20161019132058.GA17681@gmail.com>
References: <cover.1474480779.git.jpoimboe@redhat.com>
 <20161018171743.umxuwpxyafjquume@treble>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20161018171743.umxuwpxyafjquume@treble>
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


* Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> On Wed, Sep 21, 2016 at 04:03:58PM -0500, Josh Poimboeuf wrote:
> > v2:
> > - keep 'restore_all' label in "x86/entry/head/32: use local labels"
> > 
> > ---
> > 
> > Thanks to all the recent x86 entry code refactoring, most tasks' kernel
> > stacks start at the same offset right below their saved pt_regs,
> > regardless of which syscall was used to enter the kernel.  That creates
> > a nice convention which makes it straightforward to identify the end of
> > the stack, which can be useful [*] for the unwinder.
> > 
> > But there a few places where tasks don't yet follow the convention.
> > This patch set finishes the job.
> > 
> > [*] This will be useful for three upcoming proposed features:
> > 
> > - Detecting corrupt stacks in the unwinder (which will also be a force
> >   for ensuring this end of stack convention continues to be followed in
> >   the future).
> > 
> > - Printing all saved pt_regs on the stack during an oops/warning.
> > 
> > - Validating stacks in the livepatch consistency model.
> 
> Ping?

Missed this one: I expected more discussion but nobody replied so it went missing.

Will have a look later this week!

Thanks,

	Ingo