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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 C7CE1C4321E for ; Sat, 8 Sep 2018 12:10:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70BAC20652 for ; Sat, 8 Sep 2018 12:10:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70BAC20652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726709AbeIHQ4a (ORCPT ); Sat, 8 Sep 2018 12:56:30 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:37541 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726351AbeIHQ4a (ORCPT ); Sat, 8 Sep 2018 12:56:30 -0400 Received: from p4fea45ac.dip0.t-ipconnect.de ([79.234.69.172] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fyc4c-0007lv-S8; Sat, 08 Sep 2018 14:10:47 +0200 Date: Sat, 8 Sep 2018 14:10:46 +0200 (CEST) From: Thomas Gleixner To: Baoquan He cc: mingo@kernel.org, hpa@zytor.com, thgarnie@google.com, kirill.shutemov@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size In-Reply-To: <20180829021754.21850-1-bhe@redhat.com> Message-ID: References: <20180829021754.21850-1-bhe@redhat.com> 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 Wed, 29 Aug 2018, Baoquan He wrote: > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the > initial size of the direct mapping region. This is right in the > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS, > 46bit, and only 4-level mode was supported. > > Later, in commit: > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"), > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's > 5-level or 4-level. This is wrong for 4-level paging. Then when > adapt phyiscal memory region size based on available memory, it > will overflow if the amount of system RAM and the padding is bigger > than 64TB. > > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS. > > Signed-off-by: Baoquan He This lacks a fixes tag ..... Thanks, tglx