From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from e28smtp03.in.ibm.com ([122.248.162.3]) by canuck.infradead.org with esmtps (Exim 4.72 #1 (Red Hat Linux)) id 1PxCwR-0001rb-MK for kexec@lists.infradead.org; Wed, 09 Mar 2011 06:32:16 +0000 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by e28smtp03.in.ibm.com (8.14.4/8.13.1) with ESMTP id p296W8xa030902 for ; Wed, 9 Mar 2011 12:02:08 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p296W8AE872636 for ; Wed, 9 Mar 2011 12:02:08 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p296W7xw009096 for ; Wed, 9 Mar 2011 17:32:07 +1100 Message-ID: <4D771EE6.5050404@linux.vnet.ibm.com> Date: Wed, 09 Mar 2011 12:02:06 +0530 From: Mahesh Jagannath Salgaonkar MIME-Version: 1.0 Subject: Re: [PATCH 1/2] kdump: Allow shrinking of kdump region to be overridden References: <20100825002258.GD28360@kryten> In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: "Eric W. Biederman" Cc: linuxppc-dev@ozlabs.org, akpm@linux-foundation.org, kexec@lists.infradead.org, Anton Blanchard , linux-kernel@vger.kernel.org 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec