From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933638AbXCWFZJ (ORCPT ); Fri, 23 Mar 2007 01:25:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933681AbXCWFZJ (ORCPT ); Fri, 23 Mar 2007 01:25:09 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:44494 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933638AbXCWFZG (ORCPT ); Fri, 23 Mar 2007 01:25:06 -0400 Date: Fri, 23 Mar 2007 10:55:01 +0530 From: Vivek Goyal To: Michal Piotrowski Cc: Ingo Molnar , Thomas Gleixner , LKML Subject: Re: 2.6.21-rc4-rt0-kdump (was: Re: [patch] setup_boot_APIC_clock() irq-enable fix) Message-ID: <20070323052501.GA1421@in.ibm.com> Reply-To: vgoyal@in.ibm.com References: <6bffcb0e0703211338i2aa6f933ube53c6604c78e285@mail.gmail.com> <20070322093119.GA19394@elte.hu> <6bffcb0e0703220557h7ff64282qf378623452c07d03@mail.gmail.com> <4602843D.9000306@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4602843D.9000306@googlemail.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 22, 2007 at 02:27:25PM +0100, Michal Piotrowski wrote: > Michal Piotrowski napisał(a): > > On 22/03/07, Ingo Molnar wrote: > >> > >> * Michal Piotrowski wrote: > >> > >> > Hi Ingo, > >> > >> > 2.6.21-rc4-rt0 > >> > >> > BUG: at kernel/fork.c:1033 copy_process() > >> > >> thanks Michal - this is a real bug that affects upstream too. Find the > >> fix below - i've test-booted it and it fixes the warning. > > > > Problem is fixed, thanks. > > BTW. It seems that nobody uses -rt as a crash dump kernel ;) > > BUG: unable to handle kernel paging request at virtual address f7ebf8c4 > printing eip: > c1610192 > *pde = 00000000 > stopped custom tracer. > Oops: 0000 [#1] > PREEMPT > Modules linked in: > CPU: 0 > EIP: 0060:[] Not tainted VLI > EFLAGS: 00010206 (2.6.21-rc4-rt0-kdump #3) > EIP is at copy_oldmem_page+0x4a/0xd0 > eax: 000008c4 ebx: f7ebf000 ecx: 00000100 edx: 00000246 > esi: f7ebf8c4 edi: c4c520fc ebp: c4d54e30 esp: c4d54e18 > ds: 007b es: 007b fs: 00d8 gs: 0000 ss: 0068 preempt:00000001 > Process swapper (pid: 1, ti=c4d54000 task=c4d52c20 task.ti=c4d54000) > Stack: c17ab7e0 c183f982 c1969658 00000400 00000400 00037ebf c4d54e5c c16af187 > 00037ebf c4c520fc 00000400 000008c4 00000000 00000000 c4c696e0 00000400 > c4c520fc c4d54f94 c19a9cfd c4c520fc 00000400 c4d54f78 00000000 c1840996 > Call Trace: > [] read_from_oldmem+0x73/0x98 > [] vmcore_init+0x26c/0xab7 > [] init+0xaa/0x287 > [] kernel_thread_helper+0x7/0x10 > ======================= > > l *copy_oldmem_page+0x4a/0xd0 > 0xc1610148 is in copy_oldmem_page (arch/i386/kernel/crash_dump.c:35). > 30 * copying the data to a pre-allocated kernel page and then copying to user > 31 * space in non-atomic context. > 32 */ > 33 ssize_t copy_oldmem_page(unsigned long pfn, char *buf, > 34 size_t csize, unsigned long offset, int userbuf) > 35 { > 36 void *vaddr; > 37 > 38 if (!csize) > 39 return 0; > Can you please paste the disassembly of copy_oldmem_page() on your system. Not sure from where this faulting address 0xf7ebf8c4 is coming. We are still in vmcore_init(), so we should be copying the data to kernel buffers only. This looks like a valid kernel address. Can you also put some printk() here to find out from where 0xf7ebf8c4 has come? It does not look like a fixed kernel virutual address returned by kmap_atomic_pfn(). Then is it passed by kernel as a parameter to copy_oldmem_page()? Thanks Vivek