From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264966AbUEYQUF (ORCPT ); Tue, 25 May 2004 12:20:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264965AbUEYQUF (ORCPT ); Tue, 25 May 2004 12:20:05 -0400 Received: from fw.osdl.org ([65.172.181.6]:53476 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264961AbUEYQUA (ORCPT ); Tue, 25 May 2004 12:20:00 -0400 Date: Tue, 25 May 2004 09:19:52 -0700 (PDT) From: Linus Torvalds To: Keith M Wesolowski cc: Matthew Wilcox , Andrea Arcangeli , Benjamin Herrenschmidt , Andrew Morton , Linux Kernel list , Ingo Molnar , Ben LaHaise , linux-mm@kvack.org, Architectures Group Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE In-Reply-To: <20040525153501.GA19465@foobazco.org> Message-ID: References: <1085369393.15315.28.camel@gaston> <1085371988.15281.38.camel@gaston> <1085373839.14969.42.camel@gaston> <20040525034326.GT29378@dualathlon.random> <20040525114437.GC29154@parcelfarce.linux.theplanet.co.uk> <20040525153501.GA19465@foobazco.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 25 May 2004, Keith M Wesolowski wrote: > > Some sparc32 CPUs are also vulnerable to this race; in fact the > supersparc manual describes it specifically and even outlines the > compare-exchange loop using our rotten swap instruction. In our case, > the race is with a hardware walker. Yes, but the sparc32 page tables are not the same as the linux kernel page tables, so in your case it's a different path and a different page table. Only the shared case really matters (ie things that do hw/microcode walk of a page table _tree_ not a hash). Linus