[PATCH v2 1/6] mm/balloon_compaction: ignore anonymous pages

From: Konstantin Khlebnikov
Date: Sat Aug 30 2014 - 12:42:40 EST

From: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>

Sasha Levin reported KASAN splash inside isolate_migratepages_range().
Problem is in function __is_movable_balloon_page() which tests AS_BALLOON_MAP
in page->mapping->flags. This function has no protection against anonymous
pages. As result it tried to check address space flags in inside anon-vma.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Link: http://lkml.kernel.org/p/53E6CEAA.9020105@xxxxxxxxxx
Cc: stable <stable@xxxxxxxxxxxxxxx> # v3.8
include/linux/balloon_compaction.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index 089743a..53d482e 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -128,7 +128,7 @@ static inline bool page_flags_cleared(struct page *page)
static inline bool __is_movable_balloon_page(struct page *page)
struct address_space *mapping = page->mapping;
- return mapping_balloon(mapping);
+ return !PageAnon(page) && mapping_balloon(mapping);


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