* [PATCH v2] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
@ 2021-06-10 2:54 Xiyu Yang
2021-06-11 16:15 ` Will Deacon
0 siblings, 1 reply; 2+ messages in thread
From: Xiyu Yang @ 2021-06-10 2:54 UTC (permalink / raw)
To: Will Deacon, Robin Murphy, Joerg Roedel, Jordan Crouse,
Nicolin Chen, Krishna Reddy, Sai Prakash Ranjan, Xiyu Yang,
linux-arm-kernel, iommu, linux-kernel
Cc: yuanxzhang, Xin Tan
arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the
refcount of the "smmu" even though the return value is less than 0.
The reference counting issue happens in some error handling paths of
arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get()
fails, the caller functions forget to decrease the refcount of "smmu"
increased by arm_smmu_rpm_get(), causing a refcount leak.
Fix this issue by calling pm_runtime_resume_and_get() instead of
pm_runtime_get_sync() in arm_smmu_rpm_get(), which can keep the refcount
balanced in case of failure.
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 3a3847277320..1a647e0ea3eb 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -74,7 +74,7 @@ static bool using_legacy_binding, using_generic_binding;
static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
{
if (pm_runtime_enabled(smmu->dev))
- return pm_runtime_get_sync(smmu->dev);
+ return pm_runtime_resume_and_get(smmu->dev);
return 0;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v2] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
2021-06-10 2:54 [PATCH v2] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails Xiyu Yang
@ 2021-06-11 16:15 ` Will Deacon
0 siblings, 0 replies; 2+ messages in thread
From: Will Deacon @ 2021-06-11 16:15 UTC (permalink / raw)
To: iommu, Nicolin Chen, Joerg Roedel, Jordan Crouse, Robin Murphy,
Krishna Reddy, linux-kernel, Xiyu Yang, Sai Prakash Ranjan,
linux-arm-kernel
Cc: catalin.marinas, kernel-team, Will Deacon, Xin Tan, yuanxzhang
On Thu, 10 Jun 2021 10:54:29 +0800, Xiyu Yang wrote:
> arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the
> refcount of the "smmu" even though the return value is less than 0.
>
> The reference counting issue happens in some error handling paths of
> arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get()
> fails, the caller functions forget to decrease the refcount of "smmu"
> increased by arm_smmu_rpm_get(), causing a refcount leak.
>
> [...]
Applied to will (for-joerg/arm-smmu/updates), thanks!
[1/1] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
https://git.kernel.org/will/c/1adf30f198c2
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-06-10 2:54 [PATCH v2] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails Xiyu Yang
2021-06-11 16:15 ` Will Deacon
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