[PATCH 4.4 077/117] iommu/io-pgtable-arm: Ensure we free the final level on teardown

Greg Kroah-Hartman
2016-02-15T00:30:10Z

From: Will Deacon <will.deacon@arm.com>

commit 12c2ab09571e8aae3a87da2a4a452632a5fac1e5 upstream.

When tearing down page tables, we return early for the final level
since we know that we won't have any table pointers to follow.
Unfortunately, this also means that we forget to free the final level,
so we end up leaking memory.

Fix the issue by always freeing the current level, but just don't bother
to iterate over the ptes if we're at the final level.

Reported-by: Zhang Bo <zhangbo_a@xiaomi.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iommu/io-pgtable-arm.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -405,17 +405,18 @@ static void __arm_lpae_free_pgtable(stru
arm_lpae_iopte *start, *end;
unsigned long table_size;

- /* Only leaf entries at the last level */
- if (lvl == ARM_LPAE_MAX_LEVELS - 1)
- return;
-
if (lvl == ARM_LPAE_START_LVL(data))
table_size = data->pgd_size;
else
table_size = 1UL << data->pg_shift;

start = ptep;
- end = (void *)ptep + table_size;
+
+ /* Only leaf entries at the last level */
+ if (lvl == ARM_LPAE_MAX_LEVELS - 1)
+ end = ptep;
+ else
+ end = (void *)ptep + table_size;

while (ptep != end) {
arm_lpae_iopte pte = *ptep++;