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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2016-04-28 16:19:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-04-28 19:34:04 -0700
commitc2e7e00b715d3c65f301bec8559d6af4ef8098ab (patch)
treee89161188d2a485e428e9aa61690517418f75952
parentb73413647ee36406561618f68d0661d49dc47489 (diff)
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@yandex-team.ru> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memory-failure.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 78f5f2641b91..ca5acee53b7a 100644
--- a/mm/memory-failure.c
+++ b/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);