| From 83c9f1323a4b65a4a18e6cde4a8a8af456cf5efe Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 10 Jun 2021 10:54:29 +0800 |
| Subject: iommu/arm-smmu: Fix arm_smmu_device refcount leak when |
| arm_smmu_rpm_get fails |
| |
| From: Xiyu Yang <xiyuyang19@fudan.edu.cn> |
| |
| [ Upstream commit 1adf30f198c26539a62d761e45af72cde570413d ] |
| |
| 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> |
| Link: https://lore.kernel.org/r/1623293672-17954-1-git-send-email-xiyuyang19@fudan.edu.cn |
| Signed-off-by: Will Deacon <will@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 d8c6bfde6a61..128c2c87b4e5 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; |
| } |
| -- |
| 2.30.2 |
| |