This is a note to let you know that I've just added the patch titled

iommu/io-pgtable-arm-v7s: Check for leaf entry before dereferencing it

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: iommu-io-pgtable-arm-v7s-check-for-leaf-entry-before-dereferencing-it.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Mon Dec 18 14:12:34 CET 2017

From: Oleksandr Tyshchenko oleksandr_tyshchenko@epam.com Date: Mon, 27 Feb 2017 14:30:26 +0200 Subject: iommu/io-pgtable-arm-v7s: Check for leaf entry before dereferencing it

From: Oleksandr Tyshchenko oleksandr_tyshchenko@epam.com

[ Upstream commit a03849e7210277fa212779b7cd9c30e1ab6194b2 ]

Do a check for already installed leaf entry at the current level before dereferencing it in order to avoid walking the page table down with wrong pointer to the next level.

Signed-off-by: Oleksandr Tyshchenko oleksandr_tyshchenko@epam.com CC: Will Deacon will.deacon@arm.com CC: Robin Murphy robin.murphy@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/io-pgtable-arm-v7s.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -418,8 +418,12 @@ static int __arm_v7s_map(struct arm_v7s_ pte |= ARM_V7S_ATTR_NS_TABLE;

__arm_v7s_set_pte(ptep, pte, 1, cfg); - } else { + } else if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) { cptep = iopte_deref(pte, lvl); + } else { + /* We require an unmap first */ + WARN_ON(!selftest_running); + return -EEXIST; }

/* Rinse, repeat */

Patches currently in stable-queue which might be from oleksandr_tyshchenko@epam.com are

queue-4.9/iommu-io-pgtable-arm-v7s-check-for-leaf-entry-before-dereferencing-it.patch