From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754573AbcAHJGW (ORCPT ); Fri, 8 Jan 2016 04:06:22 -0500 Received: from TYO200.gate.nec.co.jp ([210.143.35.50]:53671 "EHLO tyo200.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754023AbcAHJGO convert rfc822-to-8bit (ORCPT ); Fri, 8 Jan 2016 04:06:14 -0500 X-Greylist: delayed 4395 seconds by postgrey-1.27 at vger.kernel.org; Fri, 08 Jan 2016 04:06:14 EST From: Naoya Horiguchi To: Andrew Morton CC: Andi Kleen , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi Subject: Re: [PATCH v1] mm: soft-offline: check return value in second __get_any_page() call Thread-Topic: [PATCH v1] mm: soft-offline: check return value in second __get_any_page() call Thread-Index: AQHRSeVeoHqUS9zphkuJSPbajvTt157wqDsA Date: Fri, 8 Jan 2016 07:51:59 +0000 Message-ID: <20160108075158.GA28640@hori1.linux.bs1.fc.nec.co.jp> References: <1452237748-10822-1-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1452237748-10822-1-git-send-email-n-horiguchi@ah.jp.nec.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.14] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: 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 Sorry, I forgot to notice that this specific problem is already fixed in mmotm with patch "mm: hwpoison: adjust for new thp refcounting", but considering backporting to -stable, it's easier to handle this separately. So Andrew, could you separate out the code of this patch from "mm: hwpoison: adjust for new thp refcounting"? Thanks, Naoya Horiguchi On Fri, Jan 08, 2016 at 04:22:28PM +0900, Naoya Horiguchi wrote: > I saw the following BUG_ON triggered in a testcase where a process calls > madvise(MADV_SOFT_OFFLINE) on thps, along with a background process that > calls migratepages command repeatedly (doing ping-pong among different > NUMA nodes) for the first process: > > [ 52.556731] Soft offlining page 0x60000 at 0x700000600000 > [ 52.592620] __get_any_page: 0x60000 free buddy page > [ 52.593451] page:ffffea0001800000 count:0 mapcount:-127 mapping: (null) index:0x1 > [ 52.594767] flags: 0x1fffc0000000000() > [ 52.595402] page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0) > [ 52.596602] ------------[ cut here ]------------ > [ 52.597339] kernel BUG at /src/linux-dev/include/linux/mm.h:342! > [ 52.598284] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC > [ 52.599193] Modules linked in: cfg80211 rfkill crc32c_intel serio_raw virtio_balloon i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi > [ 52.600579] CPU: 3 PID: 3035 Comm: test_alloc_gene Tainted: G O 4.4.0-rc8-v4.4-rc8-160107-1501-00000-rc8+ #74 > [ 52.600579] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 52.600579] task: ffff88007c63d5c0 ti: ffff88007c210000 task.ti: ffff88007c210000 > [ 52.600579] RIP: 0010:[] [] put_page+0x5c/0x60 > [ 52.600579] RSP: 0018:ffff88007c213e00 EFLAGS: 00010246 > [ 52.600579] RAX: 0000000000000044 RBX: ffffea0001800000 RCX: 0000000000000000 > [ 52.600579] RDX: ffff88011f50f570 RSI: 0000000000000000 RDI: ffff88011f50cc18 > [ 52.600579] RBP: ffff88007c213e08 R08: 000000000000000a R09: 000000000000149c > [ 52.600579] R10: ffff8800dac927f8 R11: 000000000000149c R12: ffffea0001800000 > [ 52.600579] R13: 0000000000060000 R14: ffffea0001800000 R15: 0000000000000065 > [ 52.600579] FS: 00007feb79d7d740(0000) GS:ffff88011f500000(0000) knlGS:0000000000000000 > [ 52.600579] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 52.600579] CR2: 00007f3032cd2000 CR3: 00000000da6c4000 CR4: 00000000000006e0 > [ 52.600579] Stack: > [ 52.600579] ffffea0001800000 ffff88007c213e28 ffffffff811eb2ee ffffea0001800000 > [ 52.600579] 00000000fffffffb ffff88007c213e70 ffffffff811eccd1 0000000000000018 > [ 52.600579] ffff88007c213e50 0000700000600000 0000700000601000 0000160000000000 > [ 52.600579] Call Trace: > [ 52.600579] [] put_hwpoison_page+0x4e/0x80 > [ 52.600579] [] soft_offline_page+0x501/0x520 > [ 52.600579] [] SyS_madvise+0x6bc/0x6f0 > [ 52.600579] [] ? fpu__restore_sig+0xcc/0x320 > [ 52.600579] [] ? do_sigaction+0x73/0x1b0 > [ 52.600579] [] ? __set_task_blocked+0x32/0x70 > [ 52.600579] [] entry_SYSCALL_64_fastpath+0x12/0x6a > [ 52.600579] Code: 8b fc ff ff 5b 5d c3 48 89 df e8 b0 fa ff ff 48 89 df 31 f6 e8 c6 7d ff ff 5b 5d c3 48 c7 c6 08 54 a2 81 48 89 df e8 a4 c5 01 00 <0f> 0b 66 90 66 66 66 66 90 55 48 89 e5 41 55 41 54 53 48 8b 47 > [ 52.600579] RIP [] put_page+0x5c/0x60 > [ 52.600579] RSP > > The root cause resides in get_any_page() which retries to get a refcount of > the page to be soft-offlined. This function calls put_hwpoison_page(), expecting > that the target page is putback to LRU list. But it can be also freed to buddy. > So the second check need to care about such case. > > Fixes: af8fae7c0886 ("mm/memory-failure.c: clean up soft_offline_page()") > Signed-off-by: Naoya Horiguchi > Cc: stable@vger.kernel.org # v3.9+ > --- > mm/memory-failure.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git v4.4-rc8/mm/memory-failure.c v4.4-rc8_patched/mm/memory-failure.c > index 8424b64..750b789 100644 > --- v4.4-rc8/mm/memory-failure.c > +++ v4.4-rc8_patched/mm/memory-failure.c > @@ -1572,7 +1572,7 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags) > * Did it turn free? > */ > ret = __get_any_page(page, pfn, 0); > - if (!PageLRU(page)) { > + if (ret == 1 && !PageLRU(page)) { > /* Drop page reference which is from __get_any_page() */ > put_hwpoison_page(page); > pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n", > -- > 1.7.1 >