From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753946Ab3KTO7e (ORCPT ); Wed, 20 Nov 2013 09:59:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32119 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827Ab3KTO7c (ORCPT ); Wed, 20 Nov 2013 09:59:32 -0500 Date: Wed, 20 Nov 2013 09:59:01 -0500 From: Vivek Goyal To: Atsushi Kumagai Cc: "bhe@redhat.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "d.hatayama@jp.fujitsu.com" , "ebiederm@xmission.com" , "dyoung@redhat.com" , "chaowang@redhat.com" Subject: Re: /proc/vmcore mmap() failure issue Message-ID: <20131120145901.GB27924@redhat.com> References: <20131113204130.GD7613@redhat.com> <5284A689.70903@jp.fujitsu.com> <20131114151359.GA3913@redhat.com> <5285EC60.1060906@jp.fujitsu.com> <20131115142617.GC6637@redhat.com> <0910DD04CBD6DE4193FCF86B9C00BE971BF592@BPXM01GP.gisp.nec.co.jp> <20131118135511.GA30637@redhat.com> <0910DD04CBD6DE4193FCF86B9C00BE971C3862@BPXM01GP.gisp.nec.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0910DD04CBD6DE4193FCF86B9C00BE971C3862@BPXM01GP.gisp.nec.co.jp> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 20, 2013 at 05:29:16AM +0000, Atsushi Kumagai wrote: > On 2013/11/18 22:56:10, kexec wrote: > > On Mon, Nov 18, 2013 at 12:51:39AM +0000, Atsushi Kumagai wrote: > > > > [..] > > > > Is there any chance that you could look into fixing this. I have no > > > > experience writing code for makedumpfile. > > > > > > I'll send a patch to fix this soon. > > > > Thanks Atsushi. > > > > Vivek > > Vivek, could you test this patch ? > > Thanks > Atsushi Kumagai > > > From: Atsushi Kumagai > Date: Wed, 20 Nov 2013 10:05:03 +0900 > Subject: [PATCH] Disable mmap() for reading fractional pages. > > Since mmap() was introduced on /proc/vmcore, it fails > for fractional pages which don't start or end at page boundary > due to kernel issue. > This patch disables mmap() temporarily for fractional pages > to avoid this issue, so mmap() will be used only for aligned pages. > > Signed-off-by: Atsushi Kumagai Hi Atsushi, Even with this patch applied I see mmap() failure. mem_map (39) mem_map : ffffea0004e00000 pfn_start : 138000 pfn_end : 140000 read /proc/vmcore with mmap() Excluding unnecessary pages : [100.0 %] |STEP [Excluding unnecessary pages] : 0.035925 seconds Excluding unnecessary pages : [100.0 %] \STEP [Excluding unnecessary pages] : 0.035774 seconds Excluding unnecessary pages : [100.0 %] -STEP [Excluding unnecessary pages] : 0.035229 seconds Copying data : [ 40.9 %] -Can't map [b98fd000-b9cfd000] with mmap() read_from_vmcore: Can't read the dump memory(/proc/vmcore) with mmap(). readpage_elf: Can't read the dump memory(/proc/vmcore). readmem: type_addr: 1, addr:bffba000, size:4096 read_pfn: Can't get the page data. Resource temporarily unavailable makedumpfile Failed. kdump: saving vmcore failed Following is part of /proc/iomem on my system. 00100000-bffc283f : System RAM 01000000-018c551d : Kernel code 018c551e-01ef3f3f : Kernel data 0204a000-02984fff : Kernel bss 2e000000-35ffffff : Crash kernel bffc2840-bfffffff : reserved This is a different system than what I used last time. So I am not sure if this is same error or something else. But one thing is clear that System RAM last page is partial and we should face mmap() failure. Thanks Vivek