This is a note to let you know that I've just added the patch titled iommu/io-pgtable-arm: 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;a=summary The filename of the patch is: iommu-io-pgtable-arm-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@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Oct 5 10:28:31 CEST 2017 From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> Date: Mon, 27 Feb 2017 14:30:25 +0200 Subject: iommu/io-pgtable-arm: Check for leaf entry before dereferencing it From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> [ Upstream commit ed46e66cc1b3d684042f92dfa2ab15ee917b4cac ] 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@xxxxxxxx> CC: Will Deacon <will.deacon@xxxxxxx> CC: Robin Murphy <robin.murphy@xxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iommu/io-pgtable-arm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -335,8 +335,12 @@ static int __arm_lpae_map(struct arm_lpa if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS) pte |= ARM_LPAE_PTE_NSTABLE; __arm_lpae_set_pte(ptep, pte, cfg); - } else { + } else if (!iopte_leaf(pte, lvl)) { cptep = iopte_deref(pte, data); + } 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@xxxxxxxx are queue-4.9/iommu-io-pgtable-arm-check-for-leaf-entry-before-dereferencing-it.patch