From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752088AbcELJau (ORCPT ); Thu, 12 May 2016 05:30:50 -0400 Received: from TYO201.gate.nec.co.jp ([210.143.35.51]:59423 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774AbcELJas convert rfc822-to-8bit (ORCPT ); Thu, 12 May 2016 05:30:48 -0400 From: Naoya Horiguchi To: Xishi Qiu CC: Vlastimil Babka , Andrew Morton , Mel Gorman , "Michal Hocko" , David Rientjes , "'Kirill A . Shutemov'" , Joonsoo Kim , Taku Izumi , "Alexander Duyck" , Johannes Weiner , Linux MM , LKML Subject: Re: [PATCH] mm: fix pfn spans two sections in has_unmovable_pages() Thread-Topic: [PATCH] mm: fix pfn spans two sections in has_unmovable_pages() Thread-Index: AQHRrDCJu6b70PKHAkG4yTRLGyCdLg== Date: Thu, 12 May 2016 09:27:43 +0000 Message-ID: <20160512092743.GA1165@hori1.linux.bs1.fc.nec.co.jp> References: <57304B9A.40504@huawei.com> <57305AD8.9090202@suse.cz> <57306038.1070907@huawei.com> In-Reply-To: <57306038.1070907@huawei.com> Accept-Language: en-US, ja-JP Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.19] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <9A74C2AE01358146B0E52D714334A235@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 09, 2016 at 06:02:32PM +0800, Xishi Qiu wrote: > On 2016/5/9 17:39, Vlastimil Babka wrote: > > > On 05/09/2016 10:34 AM, Xishi Qiu wrote: > >> If the pfn is not aligned to pageblock, the check pfn may access a next > >> pageblcok, and the next pageblock may belong to a next section. Because > >> struct page has not been alloced in the next section, so kernel panic. > >> > >> I find the caller of has_unmovable_pages() has passed a aligned pfn, so it > >> doesn't have this problem. But the earlier kernel version(e.g. v3.10) has. > >> e.g. echo xxx > /sys/devices/system/memory/soft_offline_page could trigger > >> it. The following log is from RHEL v7.1 > > > > I think has_unmovable_pages() is wrong layer where to fix such problem, as I'll explain below. > > > >> [14111.611492] Stack: > >> [14111.611494] ffffffff8115d952 0000000000000000 01ff880c393ebe40 ffff880c7ffd9000 > >> [14111.611500] ffffea0061ffffc0 ffff880c7ffd9068 0000000000000286 0000000000000001 > >> [14111.611505] ffff880c393ebe10 ffffffff811c265a 000000000187ffff 0000000000000200 > >> [14111.611511] Call Trace: > >> [14111.611516] [] ? has_unmovable_pages+0xd2/0x130 > >> [14111.611521] [] set_migratetype_isolate+0xda/0x170 > >> [14111.611526] [] soft_offline_page+0x9a/0x590 > >> [14111.611530] [] ? _kstrtoull+0x3b/0xa0 > >> [14111.611535] [] store_soft_offline_page+0xaf/0xf0 > >> [14111.611539] [] dev_attr_store+0x18/0x30 > >> [14111.611544] [] sysfs_write_file+0xc6/0x140 > >> [14111.611548] [] vfs_write+0xbd/0x1e0 > >> [14111.611551] [] SyS_write+0x58/0xb0 > >> [14111.611556] [] system_call_fastpath+0x16/0x1b > >> [14111.611559] Code: 66 66 66 90 48 83 e0 fd 0c a0 5d c3 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 66 66 66 90 48 83 c8 42 0c a0 5d c3 90 66 66 66 66 90 <8b> 07 25 00 c0 00 00 75 02 f3 c3 48 8b 07 f6 c4 80 75 0f 48 81 > >> [14111.611594] RIP [] PageHuge+0x5/0x40 > >> [14111.611598] RSP > >> [14111.611600] CR2: ffffea0062000000 > >> [14111.611604] ---[ end trace 9f780ed1def334c6 ]--- > >> [14111.678586] Kernel panic - not syncing: Fatal exception > >> > >> Signed-off-by: Xishi Qiu > > > > It's not CC'd stable, so how will this patch fix the older kernels? Also you should determine which upstream kernel versions are affected, not a RHEL derivative. > > Also is the current upstream broken or not? > > > > OK, I'll resend it later. The current upstream has not this problem. This is because soft offline has stopped changing migratetype at commit add05cecef80 ("mm: soft-offline: don't free target page in successful page migration") (or v4.1-3344-gadd05cecef80). # And the fix is available in RHEL7.2, but unfortunately not in RHEL7.1. Thanks, Naoya Horiguchi