From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f45.google.com (mail-ee0-f45.google.com [74.125.83.45]) by kanga.kvack.org (Postfix) with ESMTP id 982466B0035 for ; Thu, 12 Dec 2013 23:16:15 -0500 (EST) Received: by mail-ee0-f45.google.com with SMTP id d49so600637eek.18 for ; Thu, 12 Dec 2013 20:16:14 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id 5si538760eei.144.2013.12.12.20.16.13 for ; Thu, 12 Dec 2013 20:16:14 -0800 (PST) Date: Thu, 12 Dec 2013 23:15:54 -0500 From: Naoya Horiguchi Message-ID: <1386908154-dn8w7si1-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <52AA80C4.3040109@huawei.com> References: <52AA80C4.3040109@huawei.com> Subject: Re: [PATCH] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Jianguo Wu Cc: Andrew Morton , Mel Gorman , Andi Kleen , gong.chen@linux.intel.com, Wanpeng Li , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, Dec 13, 2013 at 11:36:36AM +0800, Jianguo Wu wrote: > 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 Thanks! Reviewed-by: Naoya Horiguchi > --- > 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 > -- 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