This is a note to let you know that I've just added the patch titled
hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage
to the 3.14-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:
hwpoison-hugetlb-lock_page-unlock_page-does-not-match-for-handling-a-free-hugepage.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b985194c8c0a130ed155b71662e39f7eaea4876f Mon Sep 17 00:00:00 2001
From: Chen Yucong <slaoub@xxxxxxxxx>
Date: Thu, 22 May 2014 11:54:15 -0700
Subject: hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage
From: Chen Yucong <slaoub@xxxxxxxxx>
commit b985194c8c0a130ed155b71662e39f7eaea4876f upstream.
For handling a free hugepage in memory failure, the race will happen if
another thread hwpoisoned this hugepage concurrently. So we need to
check PageHWPoison instead of !PageHWPoison.
If hwpoison_filter(p) returns true or a race happens, then we need to
unlock_page(hpage).
Signed-off-by: Chen Yucong <slaoub@xxxxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Tested-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1085,15 +1085,16 @@ int memory_failure(unsigned long pfn, in
return 0;
} else if (PageHuge(hpage)) {
/*
- * Check "just unpoisoned", "filter hit", and
- * "race with other subpage."
+ * Check "filter hit" and "race with other subpage."
*/
lock_page(hpage);
- if (!PageHWPoison(hpage)
- || (hwpoison_filter(p) && TestClearPageHWPoison(p))
- || (p != hpage && TestSetPageHWPoison(hpage))) {
- atomic_long_sub(nr_pages, &num_poisoned_pages);
- return 0;
+ if (PageHWPoison(hpage)) {
+ if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
+ || (p != hpage && TestSetPageHWPoison(hpage))) {
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
+ unlock_page(hpage);
+ return 0;
+ }
}
set_page_hwpoison_huge_page(hpage);
res = dequeue_hwpoisoned_huge_page(hpage);
Patches currently in stable-queue which might be from slaoub@xxxxxxxxx are
queue-3.14/hwpoison-hugetlb-lock_page-unlock_page-does-not-match-for-handling-a-free-hugepage.patch
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