Patch "mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held" has been added to the 4.1-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mm-hwpoison-fix-fail-isolate-hugetlbfs-page-w-refcount-held.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 036138080a4376e5f3e5d0cca8ac99084c5cf06e Mon Sep 17 00:00:00 2001
From: Wanpeng Li <wanpeng.li@hotmail.com>
Date: Fri, 14 Aug 2015 15:34:59 -0700
Subject: mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held

From: Wanpeng Li <wanpeng.li@hotmail.com>

commit 036138080a4376e5f3e5d0cca8ac99084c5cf06e upstream.

Hugetlbfs pages will get a refcount in get_any_page() or
madvise_hwpoison() if soft offlining through madvise.  The refcount which
is held by the soft offline path should be released if we fail to isolate
hugetlbfs pages.

Fix it by reducing the refcount for both isolation success and failure.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/memory-failure.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1589,13 +1589,12 @@ static int soft_offline_huge_page(struct
 	unlock_page(hpage);
 
 	ret = isolate_huge_page(hpage, &pagelist);
-	if (ret) {
-		/*
-		 * get_any_page() and isolate_huge_page() takes a refcount each,
-		 * so need to drop one here.
-		 */
-		put_page(hpage);
-	} else {
+	/*
+	 * get_any_page() and isolate_huge_page() takes a refcount each,
+	 * so need to drop one here.
+	 */
+	put_page(hpage);
+	if (!ret) {
 		pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
 		return -EBUSY;
 	}


Patches currently in stable-queue which might be from wanpeng.li@hotmail.com are

queue-4.1/mm-hwpoison-fix-fail-isolate-hugetlbfs-page-w-refcount-held.patch
queue-4.1/mm-hwpoison-fix-page-refcount-of-unknown-non-lru-page.patch