The patch titled
Subject: mm/memory-failure: fix race with compound page split/merge
has been added to the -mm tree. Its filename is
mm-memory-failure-fix-race-with-compound-page-split-merge.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory-failure-fix-race-with-compound-page-split-merge.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory-failure-fix-race-with-compound-page-split-merge.patch
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------------------------------------------------------
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Subject: mm/memory-failure: fix race with compound page split/merge
Get_hwpoison_page() must recheck relation between head and tail pages.
n-horiguchi said: without this recheck, the race causes kernel to pin an
irrelevant page, and finally makes kernel crash for refcount mismatch.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff -puN mm/memory-failure.c~mm-memory-failure-fix-race-with-compound-page-split-merge mm/memory-failure.c
--- a/mm/memory-failure.c~mm-memory-failure-fix-race-with-compound-page-split-merge
+++ a/mm/memory-failure.c
@@ -888,7 +888,15 @@ int get_hwpoison_page(struct page *page)
}
}
- return get_page_unless_zero(head);
+ if (get_page_unless_zero(head)) {
+ if (head == compound_head(page))
+ return 1;
+
+ pr_info("MCE: %#lx cannot catch tail\n", page_to_pfn(page));
+ put_page(head);
+ }
+
+ return 0;
}
EXPORT_SYMBOL_GPL(get_hwpoison_page);
_
Patches currently in -mm which might be from khlebnikov@xxxxxxxxxxxxxx are
mm-memory-failure-fix-race-with-compound-page-split-merge.patch
mm-rmap-replace-bug_onanon_vma-degree-with-vm_warn_on.patch
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