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Commit 1e0e635b authored by Wanpeng Li's avatar Wanpeng Li Committed by Linus Torvalds
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mm/hwpoison: fix PageHWPoison test/set race 



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: default avatarWanpeng Li <wanpeng.li@hotmail.com>
Suggested-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7d1900c7

mm/memory-failure.c

+2 −0
Original line number Diff line number Diff line
@@ -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)) {