Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753710Ab0HWSxK (ORCPT ); Mon, 23 Aug 2010 14:53:10 -0400 Received: from claw.goop.org ([74.207.240.146]:60038 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751107Ab0HWSxJ (ORCPT ); Mon, 23 Aug 2010 14:53:09 -0400 Message-ID: <4C72C390.90802@goop.org> Date: Mon, 23 Aug 2010 11:53:04 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.1 MIME-Version: 1.0 To: Ian Jackson CC: Peter Zijlstra , Linus Torvalds , Greg KH , Ian Campbell , linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk Subject: Re: [RFC] mlock/stack guard interaction fixup References: <1282391770.29609.1223.camel@localhost.localdomain> <1282460275.11348.865.camel@localhost.localdomain> <1282462386.11348.871.camel@localhost.localdomain> <1282470917.11348.891.camel@localhost.localdomain> <20100822172548.GB8957@suse.de> <19570.38608.79434.179797@chiark.greenend.org.uk> <1282580751.2605.1997.camel@laptop> <19570.44367.719276.128881@chiark.greenend.org.uk> In-Reply-To: <19570.44367.719276.128881@chiark.greenend.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 915 Lines: 20 On 08/23/2010 10:18 AM, Ian Jackson wrote: > Are you allowed to mlock a stack page which has not yet been faulted > in ? What effect does it have ? I wasn't able to find a convincing > de jure answer to this question. > > But you seem, like me, to be disagreeing with Linus's assertion that > calling mlock() on the stack is something no sane programs does ? Doing hypercalls from userspace is a silly hack to avoid putting dom0 hypercall knowledge into the kernel. mlock in that area has always been problematic (initially on Solaris, and increasingly on Linux) and we're going to have to fix it at some point. I wouldn't spend a lot of time defending it. J -- 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/