Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752746Ab1CIGcQ (ORCPT ); Wed, 9 Mar 2011 01:32:16 -0500 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:41813 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751164Ab1CIGcP (ORCPT ); Wed, 9 Mar 2011 01:32:15 -0500 Message-ID: <4D771EE6.5050404@linux.vnet.ibm.com> Date: Wed, 09 Mar 2011 12:02:06 +0530 From: Mahesh Jagannath Salgaonkar User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 MIME-Version: 1.0 To: "Eric W. Biederman" CC: Anton Blanchard , akpm@linux-foundation.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org Subject: Re: [PATCH 1/2] kdump: Allow shrinking of kdump region to be overridden References: <20100825002258.GD28360@kryten> In-Reply-To: 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: 1548 Lines: 33 On 08/25/2010 06:07 AM, Eric W. Biederman wrote: > Anton Blanchard writes: > >> On ppc64 the crashkernel region almost always overlaps an area of firmware. >> This works fine except when using the sysfs interface to reduce the kdump >> region. If we free the firmware area we are guaranteed to crash. > > That is ppc64 bug. firmware should not be in the reserved region. Any > random kernel like thing can be put in to that region at any valid > address and the fact that shrinking the region frees your firmware means > that using that region could also stomp your firmware (which I assume > would be a bad thing). The issue only happens while shrinking the region using sysfs interface. We already have checks in kexec for not to stomp over on the firmware overlap area while loading capture kernel. Currently we do a top-down allocation for the firmware region which means it sits at the top of the RMO, right in the middle of the crashdump region. We can not move the crashkernel region beyond firmware region because kernel needs its some of memory in RMO region. > > So please fix the ppc64 reservation. > > Eric > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev -- 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/