Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752973Ab0LPQ25 (ORCPT ); Thu, 16 Dec 2010 11:28:57 -0500 Received: from terminus.zytor.com ([198.137.202.10]:47025 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751153Ab0LPQ24 (ORCPT ); Thu, 16 Dec 2010 11:28:56 -0500 Message-ID: <4D0A3E31.4000109@zytor.com> Date: Thu, 16 Dec 2010 08:28:33 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101103 Fedora/1.0-0.33.b2pre.fc14 Thunderbird/3.1.6 MIME-Version: 1.0 To: Vivek Goyal CC: Yinghai Lu , "Eric W. Biederman" , Stanislaw Gruszka , Ingo Molnar , Thomas Gleixner , Maxim Uvarov , linux-kernel@vger.kernel.org, Neil Horman Subject: Re: kdump broken on 2.6.37-rc4 References: <20101208141942.GA2335@redhat.com> <4D00823A.9050808@kernel.org> <20101209124117.GA6032@redhat.com> <4D01377B.5070809@kernel.org> <20101213100848.GA2237@redhat.com> <4D0663F0.2060103@kernel.org> <4D06783C.6040009@zytor.com> <20101214224135.GB19693@redhat.com> <20101215103954.GA2243@redhat.com> <4D09958D.2040907@kernel.org> <20101216143925.GA13870@redhat.com> In-Reply-To: <20101216143925.GA13870@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1479 Lines: 48 On 12/16/2010 06:39 AM, Vivek Goyal wrote: > On Wed, Dec 15, 2010 at 08:29:01PM -0800, Yinghai Lu wrote: >> please check >> >> [PATCH] x86, crashkernel, 32bit: only try to get range under 512M >> >> Steanishlaw report kdump is 32bit is broken. >> >> in misc.c for decompresser, it will do sanity checking to make sure heap >> heap under 512M. > > Thanks Yinghai. I am wondering why on 32bit heap has to be with-in 512MB. > I think you are referring to following check in > arch/x86/boot/compressed/misc.c. > > if (end > ((-__PAGE_OFFSET-(512 <<20)-1) & 0x7fffffff)) > error("Destination address too large"); > > It was introduced here. > > commit 968de4f02621db35b8ae5239c8cfc6664fb872d8 > Author: Eric W. Biederman > Date: Thu Dec 7 02:14:04 2006 +0100 > > [PATCH] i386: Relocatable kernel support > > Eric, > > It has been long. By any chance would you remember where does above > constraint come from? > It might, in fact, be bogus; specifically a proxy for the fact that we need the kernel memory including bss and brk below the lowmem boundary, which isn't well-defined. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/