Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965019AbXHYMIY (ORCPT ); Sat, 25 Aug 2007 08:08:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751915AbXHYMIP (ORCPT ); Sat, 25 Aug 2007 08:08:15 -0400 Received: from ozlabs.org ([203.10.76.45]:54746 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750880AbXHYMIO (ORCPT ); Sat, 25 Aug 2007 08:08:14 -0400 Subject: Re: [-mm patch] enforce noreplace-smp in alternative_instructions() From: Rusty Russell To: Frederik Deweerdt Cc: Jeremy Fitzhardinge , Andrew Morton , linux-kernel@vger.kernel.org, Andi Kleen , kraxel@redhat.com In-Reply-To: <20070824082249.GG31846@slug> References: <20070822020648.5ea3a612.akpm@linux-foundation.org> <20070822202551.GB31846@slug> <20070823145038.9895784f.akpm@linux-foundation.org> <20070824060438.GE31846@slug> <46CE7EDC.9080007@goop.org> <20070824082249.GG31846@slug> Content-Type: text/plain Date: Sat, 25 Aug 2007 22:07:29 +1000 Message-Id: <1188043649.20041.81.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 35 On Fri, 2007-08-24 at 10:22 +0200, Frederik Deweerdt wrote: > [Added Gerd Hoffman and Rusty Russel to cc] > On Thu, Aug 23, 2007 at 11:46:52PM -0700, Jeremy Fitzhardinge wrote: > > Frederik Deweerdt wrote: > > > That means that even when you specify noreplace_smp, some replacing > > > takes place anyway. One of the consequences, besides noreplace_smp not > > > working as expected, is that lguest crashes when you feed it an SMP kernel > > > (I suspect that you can not replace alternatives for smp _and_ paravirt). > > > > > > > No, that should be fine. Why does lguest crash? > It dies with: > [ 0.131000] SMP alternatives: switching to UP code > lguest: bad stack page 0xc057a000 How odd! This means that the guest set the kernel to a stack which it hadn't mapped writable (or perhaps not mapped at all). I always run SMP kernels, and that seems a very strange side effect of a patching problem... Nonetheless, I did have a previous problem with a bug in the patching code which didn't show up native and did show up under lguest. Can you send your config? Do you need noreplace-smp even on 2.6.23-rc3, or only 2.6.23-rc3-mm1? Thanks, Rusty. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/