Commit 783657a7 authored Nov 29, 2012 by Naoya Horiguchi Committed by Linus Torvalds Nov 30, 2012

mm: soft offline: split thp at the beginning of soft_offline_page()

When we try to soft-offline a thp tail page, put_page() is called on the
tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page().

This patch splits thp before going into the main body of soft-offlining.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 782fd304

mm/memory-failure.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1476,9 +1476,17 @@ int soft_offline_page(struct page *page, int flags)
		{
		int ret;
		unsigned long pfn = page_to_pfn(page);
		struct page *hpage = compound_trans_head(page);

		if (PageHuge(page))
		return soft_offline_huge_page(page, flags);
		if (PageTransHuge(hpage)) {
		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
		pr_info("soft offline: %#lx: failed to split THP\n",
		pfn);
		return -EBUSY;
		}
		}

		ret = get_any_page(page, pfn, flags);
		if (ret < 0)

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