This is a note to let you know that I've just added the patch titled
mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate
successfully
to the 3.4-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-memory-failure.c-recheck-pagehuge-after-hugetlb-page-migrate-successfully.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 Mon Sep 17 00:00:00 2001
From: Jianguo Wu <[email protected]>
Date: Wed, 18 Dec 2013 17:08:54 -0800
Subject: mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate
successfully
From: Jianguo Wu <[email protected]>
commit a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 upstream.
After a successful hugetlb page migration by soft offline, the source
page will either be freed into hugepage_freelists or buddy(over-commit
page). If page is in buddy, page_hstate(page) will be NULL. It will
hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page().
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0
PGD c23762067 PUD c24be2067 PMD 0
Oops: 0000 [#1] SMP
So check PageHuge(page) after call migrate_pages() successfully.
[wujg: backport to 3.4:
- adjust context
- s/num_poisoned_pages/mce_bad_pages/]
Signed-off-by: Jianguo Wu <[email protected]>
Tested-by: Naoya Horiguchi <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/memory-failure.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1447,10 +1447,18 @@ static int soft_offline_huge_page(struct
return ret;
}
done:
- if (!PageHWPoison(hpage))
- atomic_long_add(1 << compound_trans_order(hpage),
&mce_bad_pages);
- set_page_hwpoison_huge_page(hpage);
- dequeue_hwpoisoned_huge_page(hpage);
+ /* overcommit hugetlb page will be freed to buddy */
+ if (PageHuge(hpage)) {
+ if (!PageHWPoison(hpage))
+ atomic_long_add(1 << compound_trans_order(hpage),
+ &mce_bad_pages);
+ set_page_hwpoison_huge_page(hpage);
+ dequeue_hwpoisoned_huge_page(hpage);
+ } else {
+ SetPageHWPoison(page);
+ atomic_long_inc(&mce_bad_pages);
+ }
+
/* keep elevated page count for bad page */
return ret;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/mm-memory-failure.c-recheck-pagehuge-after-hugetlb-page-migrate-successfully.patch
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