From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f180.google.com (mail-pd0-f180.google.com [209.85.192.180]) by kanga.kvack.org (Postfix) with ESMTP id DD5676B0035 for ; Thu, 12 Dec 2013 22:37:25 -0500 (EST) Received: by mail-pd0-f180.google.com with SMTP id q10so1675193pdj.25 for ; Thu, 12 Dec 2013 19:37:25 -0800 (PST) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com. [119.145.14.66]) by mx.google.com with ESMTPS id am2si445317pad.67.2013.12.12.19.37.17 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 12 Dec 2013 19:37:24 -0800 (PST) Message-ID: <52AA80C4.3040109@huawei.com> Date: Fri, 13 Dec 2013 11:36:36 +0800 From: Jianguo Wu MIME-Version: 1.0 Subject: [PATCH] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Naoya Horiguchi , Mel Gorman , Andi Kleen , gong.chen@linux.intel.com, Wanpeng Li , linux-mm@kvack.org, linux-kernel@vger.kernel.org Changelog: - Only set PageHWPoison on the error raw page if page is freed into buddy After a successful hugetlb page migration by soft offline, the source page will either be freed into hugepage_freelists or buddy(over-commit page). If page is in buddy, page_hstate(page) will be NULL. It will hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page(). [ 890.677918] BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 [ 890.685741] IP: [] dequeue_hwpoisoned_huge_page+0x131/0x1d0 [ 890.692861] PGD c23762067 PUD c24be2067 PMD 0 [ 890.697314] Oops: 0000 [#1] SMP So check PageHuge(page) after call migrate_pages() successfully. Tested-by: Naoya Horiguchi Cc: stable@vger.kernel.org Signed-off-by: Jianguo Wu --- mm/memory-failure.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b7c1716..db08af9 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1505,10 +1505,16 @@ static int soft_offline_huge_page(struct page *page, int flags) if (ret > 0) ret = -EIO; } else { - set_page_hwpoison_huge_page(hpage); - dequeue_hwpoisoned_huge_page(hpage); - atomic_long_add(1 << compound_order(hpage), - &num_poisoned_pages); + /* overcommit hugetlb page will be freed to buddy */ + if (PageHuge(page)) { + set_page_hwpoison_huge_page(hpage); + dequeue_hwpoisoned_huge_page(hpage); + atomic_long_add(1 << compound_order(hpage), + &num_poisoned_pages); + } else { + SetPageHWPoison(page); + atomic_long_inc(&num_poisoned_pages); + } } return ret; } -- 1.7.1 -- 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