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From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
To: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	Rob Clark <robdclark@chromium.org>,
	Jon Hunter <jonathanh@nvidia.com>,
	Krishna Reddy <vdumpa@nvidia.com>,
	Jordan Crouse <jordan@cosmicpenguin.net>,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	linux-arm-kernel@lists.infradead.org,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Cc: yuanxzhang@fudan.edu.cn, Xiyu Yang <xiyuyang19@fudan.edu.cn>,
	Xin Tan <tanxin.ctf@gmail.com>
Subject: [PATCH v2] iommu/arm-smmu: Fix arm_smmu_device refcount leak in address translation
Date: Thu, 10 Jun 2021 10:49:20 +0800
Message-ID: <1623293391-17261-1-git-send-email-xiyuyang19@fudan.edu.cn> (raw)

The reference counting issue happens in several exception handling paths
of arm_smmu_iova_to_phys_hard(). When those error scenarios occur, the
function forgets to decrease the refcount of "smmu" increased by
arm_smmu_rpm_get(), causing a refcount leak.

Fix this issue by jumping to "out" label when those error scenarios
occur.

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 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 6f72c4d208ca..3a3847277320 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1271,6 +1271,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
 	u64 phys;
 	unsigned long va, flags;
 	int ret, idx = cfg->cbndx;
+	phys_addr_t addr = 0;
 
 	ret = arm_smmu_rpm_get(smmu);
 	if (ret < 0)
@@ -1290,6 +1291,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
 		dev_err(dev,
 			"iova to phys timed out on %pad. Falling back to software table walk.\n",
 			&iova);
+		arm_smmu_rpm_put(smmu);
 		return ops->iova_to_phys(ops, iova);
 	}
 
@@ -1298,12 +1300,14 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
 	if (phys & ARM_SMMU_CB_PAR_F) {
 		dev_err(dev, "translation fault!\n");
 		dev_err(dev, "PAR = 0x%llx\n", phys);
-		return 0;
+		goto out;
 	}
 
+	addr = (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
+out:
 	arm_smmu_rpm_put(smmu);
 
-	return (phys & GENMASK_ULL(39, 12)) | (iova & 0xfff);
+	return addr;
 }
 
 static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
-- 
2.7.4


             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-10  2:49 Xiyu Yang [this message]
2021-06-10 22:28 ` Rob Clark
2021-06-11 16:15 ` Will Deacon

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