From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754612AbYGZDdO (ORCPT ); Fri, 25 Jul 2008 23:33:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752862AbYGZDc7 (ORCPT ); Fri, 25 Jul 2008 23:32:59 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:39260 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752835AbYGZDc6 (ORCPT ); Fri, 25 Jul 2008 23:32:58 -0400 Date: Fri, 25 Jul 2008 20:32:54 -0700 From: Nishanth Aravamudan To: gerald.schaefer@de.ibm.com Cc: schwidefsky@de.ibm.com, LKML , agl@us.ibm.com Subject: Re: s390 hugetlb oops with libhugetlbfs test-suite Message-ID: <20080726033254.GA3810@us.ibm.com> References: <20080725211035.GA19738@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080725211035.GA19738@us.ibm.com> X-Operating-System: Linux 2.6.26-rc9-00132-g9df2fe9 (x86_64) User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.07.2008 [14:10:35 -0700], Nishanth Aravamudan wrote: > Hi Gerald, > > Having noticed that the hugetlbfs code recently got an update to work > on s390, I decided to port the libhugetlbfs test-suite to work on > s390. The current development snapshot is available at > http://libhugetlbfs.ozlabs.org/snapshots/libhugetlbfs-dev-20080724.tar.gz. > You will need a patch [1] to build on s390, but it should roughly work > otherwise. The specific testcase that causes the oops is counters. > The bit set in the flags is PG_Reserved, I think. After enabling some debugging options, I got a slightly more precise stack trace. The last one I posted was for the 32-bit counters test and this one is for the 64-bit one, but appears to be the same problem (PG_reserved still being set). Bad page state in process 'counters' page:000003e040000000 flags:0x0000000000000400 mapping:0000000000000000 mapcount:0 count:0 Trying to fix it up, but a reboot is needed Backtrace: CPU: 1 Tainted: G W 2.6.26-autokern1 #1 Process counters (pid: 5365, task: 000000003855ab50, ksp: 000000002667bbc0) 0000000000000047 000000002667b7d0 0000000000000002 0000000000000000 000000002667b870 000000002667b7e8 000000002667b7e8 0000000000016f22 0000000000000000 0000000000000000 000002000000000a 000000000000000a 0000000000000000 000000002667b7d0 000000002667b7d0 000000002667b848 000000000025cb28 0000000000016f22 000000002667b7d0 000000002667b828 Call Trace: ([<0000000000016e80>] show_trace+0xd8/0xe8) [<0000000000016f40>] show_stack+0xb0/0xc0 [<000000000001766c>] dump_stack+0xa8/0xb8 [<000000000007f3da>] bad_page+0x9a/0xd4 [<00000000000802dc>] free_hot_cold_page+0xa0/0x1f8 [<00000000000804f6>] free_hot_page+0x22/0x30 [<000000000008503a>] put_page+0x136/0x144 [<00000000000a0a68>] __unmap_hugepage_range+0x398/0x3dc [<00000000000a0b00>] unmap_hugepage_range+0x54/0x7c [<000000000008d6f2>] unmap_vmas+0x152/0xb5c [<000000000009284e>] exit_mmap+0x14e/0x2fc [<000000000003b128>] mmput+0x64/0x110 [<000000000004030c>] exit_mm+0xf0/0x100 [<0000000000041fd8>] do_exit+0x268/0x7f8 [<00000000000425fe>] do_group_exit+0x96/0xc4 [<000000000004ddbc>] get_signal_to_deliver+0x350/0x378 [<000000000001e026>] do_signal+0xe6/0x87c [<0000000000024a0a>] sysc_sigpending+0xe/0x22 [<000000008000163c>] 0x8000163c I'm not quite sure yet how the hugetlb destructor (free_huge_page()/update_and_free_page()) can call free_hot_page()/free_hot_cold_page(), because the comments for both indicate they should only be used for order-0 pages. Are we somehow losing the fact that this is a compound page on s390? If anyone would like a s390-compatible version of libhugetlbfs, just let me know I can send it off-list. Thanks, Nish -- Nishanth Aravamudan IBM Linux Technology Center