From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266680AbUF3OY0 (ORCPT ); Wed, 30 Jun 2004 10:24:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266683AbUF3OY0 (ORCPT ); Wed, 30 Jun 2004 10:24:26 -0400 Received: from mail.shareable.org ([81.29.64.88]:13485 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S266680AbUF3OYP (ORCPT ); Wed, 30 Jun 2004 10:24:15 -0400 Date: Wed, 30 Jun 2004 15:23:51 +0100 From: Jamie Lokier To: Denis Vlasenko Cc: linux-kernel@vger.kernel.org, Andi Kleen , Ingo Molnar Subject: Re: Do x86 NX and AMD prefetch check cause page fault infinite loop? Message-ID: <20040630142351.GD29285@mail.shareable.org> References: <20040630013824.GA24665@mail.shareable.org> <200406300910.16396.vda@port.imtp.ilyichevsk.odessa.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200406300910.16396.vda@port.imtp.ilyichevsk.odessa.ua> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Denis Vlasenko wrote: > > This can only happen when something branches to a page with PROT_EXEC > > _not_ set, on a kernel which honours that, and the target address is a > > prefetch instruction. > > Well. To be safe, just skip prefetch instruction, always. > Hm. An attacker can supply us with whole gigabyte of > prefetches back-to-back... Better skip all prefetches, > with resheduling between every 1000 of them. You could just skip one and return from the handler. That's not a bad idea. -- Jamie