Patch "mm: migrate: hugetlb: putback destination hugepage to active list" has been added to the 4.2-stable tree

[<gregkh@linuxfoundation.org>]

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

    mm: migrate: hugetlb: putback destination hugepage to active list

to the 4.2-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-migrate-hugetlb-putback-destination-hugepage-to-active-list.patch
and it can be found in the queue-4.2 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 3aaa76e125c1dd58c9b599baa8c6021896874c12 Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date: Tue, 22 Sep 2015 14:59:14 -0700
Subject: mm: migrate: hugetlb: putback destination hugepage to active list

From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

commit 3aaa76e125c1dd58c9b599baa8c6021896874c12 upstream.

Since commit bcc54222309c ("mm: hugetlb: introduce page_huge_active")
each hugetlb page maintains its active flag to avoid a race condition
betwe= en multiple calls of isolate_huge_page(), but current kernel
doesn't set the f= lag on a hugepage allocated by migration because the
proper putback routine isn= 't called.  This means that users could
still encounter the race referred to by bcc54222309c in this special
case, so this patch fixes it.

Fixes: bcc54222309c ("mm: hugetlb: introduce page_huge_active")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Hugh Dickins <hughd@google.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/migrate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1068,7 +1068,7 @@ out:
 	if (rc != MIGRATEPAGE_SUCCESS && put_new_page)
 		put_new_page(new_hpage, private);
 	else
-		put_page(new_hpage);
+		putback_active_hugepage(new_hpage);
 
 	if (result) {
 		if (rc)


Patches currently in stable-queue which might be from n-horiguchi@ah.jp.nec.com are

queue-4.2/mm-hugetlbfs-skip-shared-vmas-when-unmapping-private-pages-to-satisfy-a-fault.patch
queue-4.2/mm-migrate-hugetlb-putback-destination-hugepage-to-active-list.patch