4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Oleksandr Tyshchenko <[email protected]> [ 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 <[email protected]> CC: Will Deacon <[email protected]> CC: Robin Murphy <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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 */
