Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753608Ab0HWJWo (ORCPT ); Mon, 23 Aug 2010 05:22:44 -0400 Received: from casper.infradead.org ([85.118.1.10]:40931 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751579Ab0HWJWm convert rfc822-to-8bit (ORCPT ); Mon, 23 Aug 2010 05:22:42 -0400 Subject: Re: [RFC] mlock/stack guard interaction fixup From: Peter Zijlstra To: Linus Torvalds Cc: 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, Jeremy Fitzhardinge In-Reply-To: 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> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Mon, 23 Aug 2010 11:22:25 +0200 Message-ID: <1282555345.2605.1520.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 736 Lines: 16 On Sun, 2010-08-22 at 11:21 -0700, Linus Torvalds wrote: > Doing hypercalls from user space on stuff that is on the stack, > rather than just copying it to some stable area is dodgy. And I > guarantee that doing the crazy mlock dance is slower than the copy, so > it's complex, fragile, _and_ slow. > That sounds broken too, not having read the initial problem and such, it sounds like the hypercall would expect the pages to stay pinned and mlock doesn't actually guarantee that at all. -- 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/