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From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: iommu@lists.linux.dev
Cc: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	netdev@vger.kernel.org
Subject: [PATCH v2 2/2] iommu/arm-smmu-v3: don't unregister on shutdown
Date: Thu, 15 Dec 2022 16:12:51 +0200	[thread overview]
Message-ID: <20221215141251.3688780-2-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20221215141251.3688780-1-vladimir.oltean@nxp.com>

Similar to SMMUv2, this driver calls iommu_device_unregister() from the
shutdown path, which removes the IOMMU groups with no coordination
whatsoever with their users - shutdown methods are optional in device
drivers. This can lead to NULL pointer dereferences in those drivers'
DMA API calls, or worse.

Instead of calling the full arm_smmu_device_remove() from
arm_smmu_device_shutdown(), let's pick only the relevant function call -
arm_smmu_device_disable() - more or less the reverse of
arm_smmu_device_reset() - and call just that from the shutdown path.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: patch is new

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 +++-
 1 file changed, 3 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 6d5df91c5c46..d4d8bfee9feb 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3854,7 +3854,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 
 static void arm_smmu_device_shutdown(struct platform_device *pdev)
 {
-	arm_smmu_device_remove(pdev);
+	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
+
+	arm_smmu_device_disable(smmu);
 }
 
 static const struct of_device_id arm_smmu_of_match[] = {
-- 
2.34.1


WARNING: multiple messages have this Message-ID (diff)
From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: iommu@lists.linux.dev
Cc: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	netdev@vger.kernel.org
Subject: [PATCH v2 2/2] iommu/arm-smmu-v3: don't unregister on shutdown
Date: Thu, 15 Dec 2022 16:12:51 +0200	[thread overview]
Message-ID: <20221215141251.3688780-2-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20221215141251.3688780-1-vladimir.oltean@nxp.com>

Similar to SMMUv2, this driver calls iommu_device_unregister() from the
shutdown path, which removes the IOMMU groups with no coordination
whatsoever with their users - shutdown methods are optional in device
drivers. This can lead to NULL pointer dereferences in those drivers'
DMA API calls, or worse.

Instead of calling the full arm_smmu_device_remove() from
arm_smmu_device_shutdown(), let's pick only the relevant function call -
arm_smmu_device_disable() - more or less the reverse of
arm_smmu_device_reset() - and call just that from the shutdown path.

Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: patch is new

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 +++-
 1 file changed, 3 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 6d5df91c5c46..d4d8bfee9feb 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3854,7 +3854,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 
 static void arm_smmu_device_shutdown(struct platform_device *pdev)
 {
-	arm_smmu_device_remove(pdev);
+	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
+
+	arm_smmu_device_disable(smmu);
 }
 
 static const struct of_device_id arm_smmu_of_match[] = {
-- 
2.34.1


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  reply	other threads:[~2022-12-15 14:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-15 14:12 [PATCH v2 1/2] iommu/arm-smmu: don't unregister on shutdown Vladimir Oltean
2022-12-15 14:12 ` Vladimir Oltean
2022-12-15 14:12 ` Vladimir Oltean [this message]
2022-12-15 14:12   ` [PATCH v2 2/2] iommu/arm-smmu-v3: " Vladimir Oltean
2023-01-10 14:02 ` [PATCH v2 1/2] iommu/arm-smmu: " Will Deacon
2023-01-10 14:02   ` Will Deacon

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