From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750865Ab1BEFhi (ORCPT ); Sat, 5 Feb 2011 00:37:38 -0500 Received: from smtp.outflux.net ([198.145.64.163]:47861 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787Ab1BEFhi (ORCPT ); Sat, 5 Feb 2011 00:37:38 -0500 Date: Fri, 4 Feb 2011 21:37:16 -0800 From: Kees Cook To: "H. Peter Anvin" Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, castet.matthieu@free.fr, tglx@linutronix.de, hpa@linux.intel.com Subject: Re: [tip:x86/urgent] x86-32: Make sure the stack is set up before we use it Message-ID: <20110205053716.GR5503@outflux.net> References: <4D41E86D.8060205@free.fr> <20110205021922.GP5503@outflux.net> <4D4CD411.6070800@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D4CD411.6070800@zytor.com> Organization: Canonical X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 04, 2011 at 08:37:37PM -0800, H. Peter Anvin wrote: > On 02/04/2011 06:19 PM, Kees Cook wrote: > > This works for me doing CPU hotplugging on ia32, but on x86_64 it hangs. > > (Both boot, though.) > > I can't reproduce the failure here, and it's hard to see how this patch > would make a significant change on 64 bits. Could you try reverting > *only* the head_64.S hunk and try it on your platform again? With the head_64.S hunk dropped, it runs fine. My highly fine-tuned test-case is: while :; do ls -la / -R >/dev/null 2>/dev/null; done & while :; do echo 0 > /sys/devices/system/cpu/cpu1/online ; echo 1 > /sys/devices/system/cpu/cpu1/online ; done & Looks good from this end. Thanks! -Kees -- Kees Cook Ubuntu Security Team