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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 55AFDC76191 for ; Mon, 15 Jul 2019 15:44:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28CD82081C for ; Mon, 15 Jul 2019 15:44:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730950AbfGOPoX (ORCPT ); Mon, 15 Jul 2019 11:44:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:36618 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730257AbfGOPoW (ORCPT ); Mon, 15 Jul 2019 11:44:22 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 3A3D5AF78; Mon, 15 Jul 2019 15:44:21 +0000 (UTC) Date: Mon, 15 Jul 2019 17:44:18 +0200 From: Joerg Roedel To: Thomas Gleixner Cc: Joerg Roedel , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Ingo Molnar , Borislav Petkov , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/3] x86/mm: Check for pfn instead of page in vmalloc_sync_one() Message-ID: <20190715154418.GA13091@suse.de> References: <20190715110212.18617-1-joro@8bytes.org> <20190715110212.18617-2-joro@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 15, 2019 at 03:08:42PM +0200, Thomas Gleixner wrote: > On Mon, 15 Jul 2019, Joerg Roedel wrote: > > > From: Joerg Roedel > > > > Do not require a struct page for the mapped memory location > > because it might not exist. This can happen when an > > ioremapped region is mapped with 2MB pages. > > > > Signed-off-by: Joerg Roedel > > Lacks a Fixes tag, hmm? Yeah, right, the question is, which commit to put in there. The problem results from two changes: 1) Introduction of !SHARED_KERNEL_PMD path in x86-32. In itself this is not a problem, and the path was only enabled for Xen-PV. 2) Huge IORemapings which use the PMD level. Also not a problem by itself, but together with !SHARED_KERNEL_PMD problematic because it requires to sync the PMD entries between all page-tables, and that was not implemented. Before PTI-x32 was merged this problem did not show up, maybe because the 32-bit Xen-PV users did not trigger it. But with PTI-x32 all PAE users run with !SHARED_KERNEL_PMD and the problem popped up. For the last patch I put the PTI-x32 enablement commit in the fixes tag, because that was the one that showed up during bisection. But more correct would probably be 5d72b4fba40e ('x86, mm: support huge I/O mapping capability I/F') Or do I miss something? Regards, Joerg