Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752738Ab0LPW6z (ORCPT ); Thu, 16 Dec 2010 17:58:55 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:38542 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751608Ab0LPW6w (ORCPT ); Thu, 16 Dec 2010 17:58:52 -0500 Message-ID: <4D0A9986.4080209@kernel.org> Date: Thu, 16 Dec 2010 14:58:14 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: Vivek Goyal CC: "H. Peter Anvin" , "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: <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> <4D0A3E31.4000109@zytor.com> <4D0A4C51.3070008@kernel.org> <20101216220117.GA2485@redhat.com> In-Reply-To: <20101216220117.GA2485@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2094 Lines: 59 On 12/16/2010 02:01 PM, Vivek Goyal wrote: > On Thu, Dec 16, 2010 at 09:28:49AM -0800, Yinghai Lu wrote: >> On 12/16/2010 08:28 AM, H. Peter Anvin wrote: >>> 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. >> >> the brk is complaining if i change that to >> >> if (end > ((-__PAGE_OFFSET-(128 <<20)-1) & 0x7fffffff)) >> error("Destination address too large"); >> > > Yinghai, > > On my system above change works fine and I can boot into second kernel. So > it will boil down to knowing what are the exact constraints on heap for > decompression and for 32bit can we allow heap upto 896MB or not. really? what is you CONFIG_PAGE_OFFSET? 0x40000000 or 0xc0000000? Yinghai -- 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/