On 14/12/17 11:03, Jean-Philippe Brucker wrote:
Kasan reports a double free when finalise_stage_fn fails: the io_pgtable
ops are freed by arm_smmu_domain_finalise and then again by
arm_smmu_domain_free. Prevent this by leaving pgtbl_ops empty on failure.

It might be a tiny bit more consistent to simply clear the domain ops again upon failure (cf. how arm_smmu_attach_dev() treats smmu_domain->smmu), but I'm sure nobody really cares that much:

Reviewed-by: Robin Murphy <robin.mur...@arm.com>

Fixes: 48ec83bcbcf5 ("iommu/arm-smmu: Add initial driver support for ARM SMMUv3 
devices")
Signed-off-by: Jean-Philippe Brucker <jean-philippe.bruc...@arm.com>
---
  drivers/iommu/arm-smmu-v3.c | 8 +++++---
  1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index f122071688fd..db4281d0e269 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1698,13 +1698,15 @@ static int arm_smmu_domain_finalise(struct iommu_domain 
*domain)
        domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
        domain->geometry.aperture_end = (1UL << ias) - 1;
        domain->geometry.force_aperture = true;
-       smmu_domain->pgtbl_ops = pgtbl_ops;
ret = finalise_stage_fn(smmu_domain, &pgtbl_cfg);
-       if (ret < 0)
+       if (ret < 0) {
                free_io_pgtable_ops(pgtbl_ops);
+               return ret;
+       }
- return ret;
+       smmu_domain->pgtbl_ops = pgtbl_ops;
+       return 0;
  }
static __le64 *arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)

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