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mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully

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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().

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
  IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0
  PGD c23762067 PUD c24be2067 PMD 0
  Oops: 0000 [#1] SMP

So check PageHuge(page) after call migrate_pages() successfully.

Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jianguo Wu 2013-12-18 17:08:54 -08:00 committed by Linus Torvalds
parent 6815bf3f23
commit a49ecbcd7b
1 changed files with 10 additions and 4 deletions
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14
mm/memory-failure.c
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@ -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;
}