From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bNxU1-0005VU-EU for kexec@lists.infradead.org; Fri, 15 Jul 2016 07:24:29 +0000 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u6F7NYoZ053276 for ; Fri, 15 Jul 2016 03:24:04 -0400 Received: from e23smtp03.au.ibm.com (e23smtp03.au.ibm.com [202.81.31.145]) by mx0a-001b2d01.pphosted.com with ESMTP id 246kcjm9m2-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 15 Jul 2016 03:24:03 -0400 Received: from localhost by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 15 Jul 2016 17:24:01 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 8E2FF3578053 for ; Fri, 15 Jul 2016 17:23:58 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u6F7NwXJ23527446 for ; Fri, 15 Jul 2016 17:23:58 +1000 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u6F7Nw8u019035 for ; Fri, 15 Jul 2016 17:23:58 +1000 Received: from [9.124.158.81] ([9.124.158.81]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u6F7Nv6U019016 for ; Fri, 15 Jul 2016 17:23:58 +1000 Subject: Re: IO memory read from /proc/vmcore leads to hang. References: <57841399.1030703@cisco.com> From: Mahesh Jagannath Salgaonkar Date: Fri, 15 Jul 2016 12:53:57 +0530 MIME-Version: 1.0 In-Reply-To: <57841399.1030703@cisco.com> Message-Id: 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" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: kexec@lists.infradead.org On 07/12/2016 03:16 AM, Daniel Walker wrote: > > Hi, > > I found found that on my Powerpc machine there is some IO memory which > will cause the box to hang if I read it. It's a custom device that was > added to the board for a special purpose. > > I was looking for a way to exclude this memory from the dump, and while > doing that I found that kexec makes a list of memory segments that go > into the core file. I was wondering why most of the kexec architecture > don't appear to exclude device memory like what's listed in /proc/iomem. > > Is there a good reason why that's not the case? Kexec/Kdump is designed to capture entire old kernel's memory that will be available in /proc/vmcore. There is a different userspace tool called 'makedumpfile' (https://sourceforge.net/projects/makedumpfile/), which can be used to exclude certain memory pages from the dump while reading from /proc/vmcore. See if that helps you. Thanks, -Mahesh. > > Daniel > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec