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mm/hwpoison: fix PageHWPoison test/set race

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There is a race between madvise_hwpoison path and memory_failure:

 CPU0					CPU1

madvise_hwpoison
get_user_pages_fast
PageHWPoison check (false)
					memory_failure
					TestSetPageHWPoison
soft_offline_page
PageHWPoison check (true)
return -EBUSY (without put_page)

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wanpeng Li 2015-09-08 15:03:13 -07:00 committed by Linus Torvalds
parent 7d1900c744
commit 1e0e635be8
1 changed files with 2 additions and 0 deletions
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2
mm/memory-failure.c
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@ -1719,6 +1719,8 @@ int soft_offline_page(struct page *page, int flags)
if (PageHWPoison(page)) {
pr_info("soft offline: %#lx page already poisoned\n", pfn);
if (flags & MF_COUNT_INCREASED)
put_page(page);
return -EBUSY;
}
if (!PageHuge(page) && PageTransHuge(hpage)) {