From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07345C41514 for ; Tue, 20 Aug 2019 11:16:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0E332070B for ; Tue, 20 Aug 2019 11:16:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729742AbfHTLQw (ORCPT ); Tue, 20 Aug 2019 07:16:52 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:51640 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728426AbfHTLQv (ORCPT ); Tue, 20 Aug 2019 07:16:51 -0400 Received: from p5de0b6c5.dip0.t-ipconnect.de ([93.224.182.197] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1i0282-00032z-Rg; Tue, 20 Aug 2019 13:16:42 +0200 Date: Tue, 20 Aug 2019 13:16:41 +0200 (CEST) From: Thomas Gleixner To: Peter Zijlstra cc: Song Liu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com, stable@vger.kernel.org, Joerg Roedel , Dave Hansen , Andy Lutomirski Subject: Re: [PATCH] x86/mm/pti: in pti_clone_pgtable() don't increase addr by PUD_SIZE In-Reply-To: <20190820100055.GI2332@hirez.programming.kicks-ass.net> Message-ID: References: <20190820075128.2912224-1-songliubraving@fb.com> <20190820100055.GI2332@hirez.programming.kicks-ass.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 20 Aug 2019, Peter Zijlstra wrote: > What that code wants to do is skip to the end of the pud, a pmd_size > increase will not do that. And right below this, there's a second > instance of this exact pattern. > > Did I get the below right? > > --- > diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c > index b196524759ec..32b20b3cb227 100644 > --- a/arch/x86/mm/pti.c > +++ b/arch/x86/mm/pti.c > @@ -330,12 +330,14 @@ pti_clone_pgtable(unsigned long start, unsigned long end, > > pud = pud_offset(p4d, addr); > if (pud_none(*pud)) { > + addr &= PUD_MASK; > addr += PUD_SIZE; round_up(addr, PUD_SIZE); perhaps? > continue; > } > > pmd = pmd_offset(pud, addr); > if (pmd_none(*pmd)) { > + addr &= PMD_MASK; > addr += PMD_SIZE; > continue; > } >