On 2021-06-09 14:35, 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.
Fix this issue by calling arm_smmu_rpm_put() or jumping to the "rpm_put"
label when arm_smmu_rpm_get() fails.
If only there was some kind of helper function which could encapsulate
the correct expected behaviour in a single place...
In fact with the new pm_runtime_resume_and_get() API I think these two
patches boil down to a one-line change.
Thanks,
Robin.
Signed-off-by: Xiyu Yang <xiyuyan...@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin....@gmail.com>
---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c
b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 6f72c4d208ca..177ee54c5534 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -840,7 +840,7 @@ static void arm_smmu_destroy_domain_context(struct
iommu_domain *domain)
ret = arm_smmu_rpm_get(smmu);
if (ret < 0)
- return;
+ goto rpm_put;
/*
* Disable the context bank and free the page tables before freeing
@@ -857,6 +857,7 @@ static void arm_smmu_destroy_domain_context(struct
iommu_domain *domain)
free_io_pgtable_ops(smmu_domain->pgtbl_ops);
__arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx);
+rpm_put:
arm_smmu_rpm_put(smmu);
}
@@ -1153,7 +1154,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
ret = arm_smmu_rpm_get(smmu);
if (ret < 0)
- return ret;
+ goto rpm_put;
/* Ensure that the domain is finalised */
ret = arm_smmu_init_domain_context(domain, smmu, dev);
@@ -1404,7 +1405,7 @@ static struct iommu_device *arm_smmu_probe_device(struct
device *dev)
ret = arm_smmu_rpm_get(smmu);
if (ret < 0)
- goto out_cfg_free;
+ goto rpm_put;
ret = arm_smmu_master_alloc_smes(dev);
arm_smmu_rpm_put(smmu);
@@ -1417,6 +1418,8 @@ static struct iommu_device *arm_smmu_probe_device(struct
device *dev)
return &smmu->iommu;
+rpm_put:
+ arm_smmu_rpm_put(smmu);
out_cfg_free:
kfree(cfg);
out_free:
@@ -1438,8 +1441,10 @@ static void arm_smmu_release_device(struct device *dev)
smmu = cfg->smmu;
ret = arm_smmu_rpm_get(smmu);
- if (ret < 0)
+ if (ret < 0) {
+ arm_smmu_rpm_put(smmu);
return;
+ }
arm_smmu_master_free_smes(cfg, fwspec);
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