From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f172.google.com (mail-pd0-f172.google.com [209.85.192.172]) by kanga.kvack.org (Postfix) with ESMTP id 9A74D6B0032 for ; Tue, 21 Apr 2015 00:20:34 -0400 (EDT) Received: by pdbnk13 with SMTP id nk13so229261497pdb.0 for ; Mon, 20 Apr 2015 21:20:34 -0700 (PDT) Received: from tyo201.gate.nec.co.jp (TYO201.gate.nec.co.jp. [210.143.35.51]) by mx.google.com with ESMTPS id nz1si1058209pbb.33.2015.04.20.21.20.33 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 20 Apr 2015 21:20:33 -0700 (PDT) From: Naoya Horiguchi Subject: [PATCH] mm: soft-offline: fix num_poisoned_pages counting on concurrent events Date: Tue, 21 Apr 2015 04:18:28 +0000 Message-ID: <1429589902-2765-1-git-send-email-n-horiguchi@ah.jp.nec.com> Content-Language: ja-JP Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Dean Nelson , Andi Kleen , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi If multiple soft offline events hit one free page/hugepage concurrently, soft_offline_page() can handle the free page/hugepage multiple times, which makes num_poisoned_pages counter increased more than once. This patch fixes this wrong counting by checking TestSetPageHWPoison for normal papes and by checking the return value of dequeue_hwpoisoned_huge_pa= ge() for hugepages. Signed-off-by: Naoya Horiguchi Cc: stable@vger.kernel.org # v3.14+ --- # This problem might happen before 3.14, but it's rare and non-critical, # so I want this patch to be backported to stable trees only if the patch # cleanly applies (i.e. v3.14+). --- mm/memory-failure.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git v4.0.orig/mm/memory-failure.c v4.0/mm/memory-failure.c index 2cc1d578144b..72a5224c8084 100644 --- v4.0.orig/mm/memory-failure.c +++ v4.0/mm/memory-failure.c @@ -1721,12 +1721,12 @@ int soft_offline_page(struct page *page, int flags) } else if (ret =3D=3D 0) { /* for free pages */ if (PageHuge(page)) { set_page_hwpoison_huge_page(hpage); - dequeue_hwpoisoned_huge_page(hpage); - atomic_long_add(1 << compound_order(hpage), + if (!dequeue_hwpoisoned_huge_page(hpage)) + atomic_long_add(1 << compound_order(hpage), &num_poisoned_pages); } else { - SetPageHWPoison(page); - atomic_long_inc(&num_poisoned_pages); + if (!TestSetPageHWPoison(page)) + atomic_long_inc(&num_poisoned_pages); } } unset_migratetype_isolate(page, MIGRATE_MOVABLE); --=20 2.1.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org