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

    mm: fix process accidentally killed by mce because of huge page migration

to the 3.10-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-fix-process-accidentally-killed-by-mce-because-of-huge-page-migration.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From [email protected]  Tue Feb 18 14:12:39 2014
From: Xishi Qiu <[email protected]>
Date: Fri, 14 Feb 2014 10:33:35 +0800
Subject: mm: fix process accidentally killed by mce because of huge page 
migration
To: Naoya Horiguchi <[email protected]>, Greg Kroah-Hartman 
<[email protected]>
Cc: <[email protected]>, <[email protected]>, Linux MM 
<[email protected]>, <[email protected]>, Xishi Qiu 
<[email protected]>, Li Zefan <[email protected]>, Andrew Morton 
<[email protected]>
Message-ID: <[email protected]>

From: Xishi Qiu <[email protected]>

Based on c8721bbbdd36382de51cd6b7a56322e0acca2414 upstream, but only the
bugfix portion pulled out.

Hi Naoya or Greg,

We found a bug in 3.10.x.
The problem is that we accidentally have a hwpoisoned hugepage in free
hugepage list. It could happend in the the following scenario:

        process A                           process B

  migrate_huge_page
  put_page (old hugepage)
    linked to free hugepage list
                                     hugetlb_fault
                                       hugetlb_no_page
                                         alloc_huge_page
                                           dequeue_huge_page_vma
                                             dequeue_huge_page_node
                                               (steal hwpoisoned hugepage)
  set_page_hwpoison_huge_page
  dequeue_hwpoisoned_huge_page
    (fail to dequeue)

I tested this bug, one process keeps allocating huge page, and I 
use sysfs interface to soft offline a huge page, then received:
"MCE: Killing UCP:2717 due to hardware memory corruption fault at 8200034"

Upstream kernel is free from this bug because of these two commits:

f15bdfa802bfa5eb6b4b5a241b97ec9fa1204a35
mm/memory-failure.c: fix memory leak in successful soft offlining

c8721bbbdd36382de51cd6b7a56322e0acca2414
mm: memory-hotplug: enable memory hotplug to handle hugepage

The first one, although the problem is about memory leak, this patch
moves unset_migratetype_isolate(), which is important to avoid the race.
The latter is not a bug fix and it's too big, so I rewrite a small one.

The following patch can fix this bug.(please apply f15bdfa802bf first)

Signed-off-by: Xishi Qiu <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 mm/hugetlb.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -21,6 +21,7 @@
 #include <linux/rmap.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
+#include <linux/page-isolation.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -517,9 +518,15 @@ static struct page *dequeue_huge_page_no
 {
        struct page *page;
 
-       if (list_empty(&h->hugepage_freelists[nid]))
+       list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
+               if (!is_migrate_isolate_page(page))
+                       break;
+       /*
+        * if 'non-isolated free hugepage' not found on the list,
+        * the allocation fails.
+        */
+       if (&h->hugepage_freelists[nid] == &page->lru)
                return NULL;
-       page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
        list_move(&page->lru, &h->hugepage_activelist);
        set_page_refcounted(page);
        h->free_huge_pages--;


Patches currently in stable-queue which might be from [email protected] are

queue-3.10/mm-memory-failure.c-fix-memory-leak-in-successful-soft-offlining.patch
queue-3.10/mm-fix-process-accidentally-killed-by-mce-because-of-huge-page-migration.patch
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