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Subject[patch 07/12] powerpc: Fix size check for hugetlbfs
-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

My "slices" address space management code that was added in 2.6.22
implementation of get_unmapped_area() doesn't properly check that the
size is a multiple of the requested page size. This allows userland to
create VMAs that aren't a multiple of the huge page size with hugetlbfs
(since hugetlbfs entirely relies on get_unmapped_area() to do that
checking) which leads to a kernel BUG() when such areas are torn down.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/powerpc/mm/slice.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -405,6 +405,8 @@ unsigned long slice_get_unmapped_area(un

if (len > mm->task_size)
return -ENOMEM;
+ if (len & ((1ul << pshift) - 1))
+ return -EINVAL;
if (fixed && (addr & ((1ul << pshift) - 1)))
return -EINVAL;
if (fixed && addr > (mm->task_size - len))
--
-
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