2020-12-07 11:28:02

by Tian Tao

Subject: [PATCH] iommu/arm-smmu-v3: Fix not checking return value about devm_add_action

Use devm_add_action_or_reset to avoid the situation where the release
function is not called when devm_add_action returns an error.

Signed-off-by: Tian Tao <[email protected]>

v2:
check the return value about evm_add_action_or_reset()
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 2ddf5ec..76c28e7 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2680,7 +2680,8 @@ static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
ret = -ENOMEM;
} else {
cmdq->valid_map = bitmap;
- devm_add_action(smmu->dev, arm_smmu_cmdq_free_bitmap, bitmap);
+ ret = devm_add_action_or_reset(smmu->dev,
+ arm_smmu_cmdq_free_bitmap, bitmap);
}

return ret;
@@ -2938,7 +2939,7 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
}

/* Add callback to free MSIs on teardown */
- devm_add_action(dev, arm_smmu_free_msis, dev);
+ devm_add_action_or_reset(dev, arm_smmu_free_msis, dev);
}

static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
--
2.7.4

2020-12-07 11:34:17

by Will Deacon

Subject: Re: [PATCH] iommu/arm-smmu-v3: Fix not checking return value about devm_add_action

On Mon, Dec 07, 2020 at 07:23:29PM +0800, Tian Tao wrote:
> Use devm_add_action_or_reset to avoid the situation where the release
> function is not called when devm_add_action returns an error.
>
> Signed-off-by: Tian Tao <[email protected]>
>
> v2:
> check the return value about evm_add_action_or_reset()
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 2ddf5ec..76c28e7 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2680,7 +2680,8 @@ static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
> ret = -ENOMEM;
> } else {
> cmdq->valid_map = bitmap;
> - devm_add_action(smmu->dev, arm_smmu_cmdq_free_bitmap, bitmap);
> + ret = devm_add_action_or_reset(smmu->dev,
> + arm_smmu_cmdq_free_bitmap, bitmap);
> }
>
> return ret;
> @@ -2938,7 +2939,7 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
> }
>
> /* Add callback to free MSIs on teardown */
> - devm_add_action(dev, arm_smmu_free_msis, dev);
> + devm_add_action_or_reset(dev, arm_smmu_free_msis, dev);

Hmm, but you don't propagate the error here so couldn't this lead to a
use-after-free?

Will