2024-03-29 09:52:39

by Aleksandr Aprelkov

Subject: [PATCH] iommu/arm-smmu-v3: Free MSIs in case of ENOMEM

If devm_add_action() returns ENOMEM, then MSIs allocated but
not freed on teardown.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 166bdbd23161 ("iommu/arm-smmu: Add support for MSI on SMMUv3")
Signed-off-by: Aleksandr Aprelkov <[email protected]>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

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 41f93c3ab160..136d0cdce6a9 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3402,7 +3402,12 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
smmu->priq.q.irq = msi_get_virq(dev, PRIQ_MSI_INDEX);

/* Add callback to free MSIs on teardown */
- devm_add_action(dev, arm_smmu_free_msis, dev);
+ ret = devm_add_action(dev, arm_smmu_free_msis, dev);
+ if (ret) {
+ dev_warn(dev, "failed to add free MSIs callback - falling back to wired irqs\n");
+ arm_smmu_free_msis(dev);
+ return;
+ }
}

static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
--
2.34.1

2024-04-01 16:58:08

by Jonathan Cameron

Subject: Re: [PATCH] iommu/arm-smmu-v3: Free MSIs in case of ENOMEM

On Fri, 29 Mar 2024 16:51:33 +0700
Aleksandr Aprelkov <[email protected]> wrote:

> If devm_add_action() returns ENOMEM, then MSIs allocated but
> not freed on teardown.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 166bdbd23161 ("iommu/arm-smmu: Add support for MSI on SMMUv3")
> Signed-off-by: Aleksandr Aprelkov <[email protected]>

I've not checked this is an actual bug (though it looks like one from
the context of the patch - the comment below is just about
how you fix it.

> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> 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 41f93c3ab160..136d0cdce6a9 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -3402,7 +3402,12 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
> smmu->priq.q.irq = msi_get_virq(dev, PRIQ_MSI_INDEX);
>
> /* Add callback to free MSIs on teardown */
> - devm_add_action(dev, arm_smmu_free_msis, dev);
> + ret = devm_add_action(dev, arm_smmu_free_msis, dev);

Use devm_add_action_or_reset() which exists to solve the case of devm registration failing.


> + if (ret) {
> + dev_warn(dev, "failed to add free MSIs callback - falling back to wired irqs\n");
> + arm_smmu_free_msis(dev);
> + return;
> + }
> }
>
> static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)