Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757599AbdIIPfZ (ORCPT ); Sat, 9 Sep 2017 11:35:25 -0400 Received: from mail-qk0-f173.google.com ([209.85.220.173]:35908 "EHLO mail-qk0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753824AbdIIPfX (ORCPT ); Sat, 9 Sep 2017 11:35:23 -0400 X-Google-Smtp-Source: AOwi7QD/zFXkTN/4CsY/5D9+h9i8o8AH0vPgxWuB+5/ixsTYVquHBe0on6A6YPXfsvCt6RirjPWrUQ== Subject: Re: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO) To: Tycho Andersen , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , x86@kernel.org References: <20170907173609.22696-1-tycho@docker.com> <20170907173609.22696-4-tycho@docker.com> From: Laura Abbott Message-ID: Date: Sat, 9 Sep 2017 08:35:17 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170907173609.22696-4-tycho@docker.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 564 Lines: 21 On 09/07/2017 10:36 AM, Tycho Andersen wrote: > +static inline struct xpfo *lookup_xpfo(struct page *page) > +{ > + struct page_ext *page_ext = lookup_page_ext(page); > + > + if (unlikely(!page_ext)) { > + WARN(1, "xpfo: failed to get page ext"); > + return NULL; > + } > + > + return (void *)page_ext + page_xpfo_ops.offset; > +} > + Just drop the WARN. On my arm64 UEFI machine this spews warnings under most normal operation. This should be normal for some situations but I haven't had the time to dig into why this is so pronounced on arm64. Thanks, Laura