The reference counting issue happens in several exception handling paths
of arm_smmu_iova_to_phys_hard(). When those error scenarios occur, the
function forgets to decrease the refcount of "smmu" increased by
arm_smmu_rpm_get(), causing a refcount leak.
Fix this issue by jumping to "out" label when those error scenarios
occur.
Signed-off-by: Xiyu Yang <[email protected]>
Signed-off-by: Xin Tan <[email protected]>
---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 6f72c4d208ca..3a3847277320 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1271,6 +1271,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
u64 phys;
unsigned long va, flags;
int ret, idx = cfg->cbndx;
+ phys_addr_t addr = 0;
ret = arm_smmu_rpm_get(smmu);
if (ret < 0)
@@ -1290,6 +1291,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
dev_err(dev,
"iova to phys timed out on %pad. Falling back to software table walk.\n",
&iova);
+ arm_smmu_rpm_put(smmu);
return ops->iova_to_phys(ops, iova);
}
@@ -1298,12 +1300,14 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
if (phys & ARM_SMMU_CB_PAR_F) {
dev_err(dev, "translation fault!\n");
dev_err(dev, "PAR = 0x%llx\n", phys);
- return 0;
+ goto out;
}
+ addr = (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
+out:
arm_smmu_rpm_put(smmu);
- return (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
+ return addr;
}
static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
--
2.7.4
On Wed, Jun 9, 2021 at 7:50 PM Xiyu Yang <[email protected]> wrote:
>
> The reference counting issue happens in several exception handling paths
> of arm_smmu_iova_to_phys_hard(). When those error scenarios occur, the
> function forgets to decrease the refcount of "smmu" increased by
> arm_smmu_rpm_get(), causing a refcount leak.
>
> Fix this issue by jumping to "out" label when those error scenarios
> occur.
>
> Signed-off-by: Xiyu Yang <[email protected]>
> Signed-off-by: Xin Tan <[email protected]>
> ---
> drivers/iommu/arm/arm-smmu/arm-smmu.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index 6f72c4d208ca..3a3847277320 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -1271,6 +1271,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
> u64 phys;
> unsigned long va, flags;
> int ret, idx = cfg->cbndx;
> + phys_addr_t addr = 0;
>
> ret = arm_smmu_rpm_get(smmu);
> if (ret < 0)
> @@ -1290,6 +1291,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
> dev_err(dev,
> "iova to phys timed out on %pad. Falling back to software table walk.\n",
> &iova);
> + arm_smmu_rpm_put(smmu);
> return ops->iova_to_phys(ops, iova);
I suppose you could also:
addr = ops->iov_to_phys(...);
goto out;
but either way,
Reviewed-by: Rob Clark <[email protected]>
> }
>
> @@ -1298,12 +1300,14 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
> if (phys & ARM_SMMU_CB_PAR_F) {
> dev_err(dev, "translation fault!\n");
> dev_err(dev, "PAR = 0x%llx\n", phys);
> - return 0;
> + goto out;
> }
>
> + addr = (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
> +out:
> arm_smmu_rpm_put(smmu);
>
> - return (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
> + return addr;
> }
>
> static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
> --
> 2.7.4
>
On Thu, 10 Jun 2021 10:49:20 +0800, Xiyu Yang wrote:
> The reference counting issue happens in several exception handling paths
> of arm_smmu_iova_to_phys_hard(). When those error scenarios occur, the
> function forgets to decrease the refcount of "smmu" increased by
> arm_smmu_rpm_get(), causing a refcount leak.
>
> Fix this issue by jumping to "out" label when those error scenarios
> occur.
Applied to will (for-joerg/arm-smmu/updates), thanks!
[1/1] iommu/arm-smmu: Fix arm_smmu_device refcount leak in address translation
https://git.kernel.org/will/c/7c8f176d6a3f
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev