Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751501AbdIKPDq (ORCPT ); Mon, 11 Sep 2017 11:03:46 -0400 Received: from mail-pg0-f42.google.com ([74.125.83.42]:34160 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715AbdIKPDp (ORCPT ); Mon, 11 Sep 2017 11:03:45 -0400 X-Google-Smtp-Source: ADKCNb5us13TDqxYwsXXjdWVyW0u2zQ/vHyqXRSF8neu3P6ScGFCdzJ0IAars++rYN5uICN4cSl+9Q== Date: Mon, 11 Sep 2017 08:03:42 -0700 From: Tycho Andersen To: Laura Abbott Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , x86@kernel.org Subject: Re: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO) Message-ID: <20170911150342.kf6n5ce4aldqy27a@docker> References: <20170907173609.22696-1-tycho@docker.com> <20170907173609.22696-4-tycho@docker.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 743 Lines: 24 On Sat, Sep 09, 2017 at 08:35:17AM -0700, Laura Abbott wrote: > 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. Will do, thanks! If you figure out under what conditions it's normal, I'd be curious :) Tycho