From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752460AbaEURfT (ORCPT ); Wed, 21 May 2014 13:35:19 -0400 Received: from terminus.zytor.com ([198.137.202.10]:39653 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760AbaEURfR (ORCPT ); Wed, 21 May 2014 13:35:17 -0400 Message-ID: <537CE3C2.8030601@zytor.com> Date: Wed, 21 May 2014 10:34:58 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Linux Kernel Mailing List CC: Thomas Gleixner , Ingo Molnar , x86@kernel.org Subject: Re: Bisected 3.9 regression: Corrupted low memory (x86, mm: Move reserving low memory later in initialization) References: In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/21/2014 06:31 AM, Rafał Miłecki wrote: > On 16 May 2014 07:29, Rafał Miłecki wrote: >> Sorry for the late report, this bug appears on my old notebook I don't >> commonly use. Anyway, I've noticed following problem when using >> 3.15-rc1: >> >> Corrupted low memory at ffff88000000be98 (be98 phys) = b02a000400000000 > > Ping? > It's not a regression, but rather a progression: the checker now does what it claims to do, which is to check for low memory corruption. However, the checker is also rather useless as anything other than a diagnostic tool. It tells you that your BIOS is corrupting memory, and the solution to that is to reserve the memory, which we already do. All the checker tells us is that on your system, yes, we really do need to reserve the memory. -hpa