From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755575Ab1KQEoj (ORCPT ); Wed, 16 Nov 2011 23:44:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54371 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755094Ab1KQEoi (ORCPT ); Wed, 16 Nov 2011 23:44:38 -0500 Message-ID: <4EC491B3.705@redhat.com> Date: Thu, 17 Nov 2011 12:46:43 +0800 From: Dave Young User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110323 Thunderbird/3.1.9 MIME-Version: 1.0 To: Tejun Heo CC: WANG Cong , kexec@lists.infradead.org, tim@edgecast.com, linux-kernel@vger.kernel.org Subject: Re: Crash during vmcore_init References: <1318376345.2050.20.camel@boudreau> <1321296650.2066.17.camel@boudreau> <4EC21F67.10905@redhat.com> <1321396371.4198.5.camel@boudreau> <4EC31E55.6040809@redhat.com> <1321467647.2137.4.camel@boudreau> <4EC47FCA.5090908@redhat.com> 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 On 11/17/2011 12:34 PM, Tejun Heo wrote: > Hello, > > On Wed, Nov 16, 2011 at 7:30 PM, Dave Young wrote: >> This addr is converted to an invalid phys address, > > I'm a bit lost on the context here. Who's calling per_cpu_ptr_to_phys()? It's drivers/base/cpu.c : show_crash_notes() > >> looking the code below: >> if (in_first_chunk) { >> if (!is_vmalloc_addr(addr)) >> return __pa(addr); >> else >> return page_to_phys(vmalloc_to_page(addr)); >> } else >> return page_to_phys(pcpu_addr_to_page(addr)); >> >> I dont understand per cpu allocation well, if addr is not in first chunk >> then it should be in vmalloc area? > > Yes, it is. First chunk can be embedded in the kernel linear address > space but from the second one, it's always set up from the top of the > vmalloc area with the same offset layout as the first chunk. in this case ffff880667c19ad0 fall out of vmalloc area and it's not in first chunk also. > >> Tejun, do you have any idea about this? > > Can you please tell me how to reproduce the problem? I'll try to find > out what's going on. make sure kernel support CRASH DUMP, then cat /sys/devices/system/cpu/cpu[x]/crash_notes Tim Hartrick reported the problem when test kdump. But I can not reproduce this. I think tim can help to test > > Thanks. > -- Thanks Dave