This is a note to let you know that I've just added the patch titled
iommu/arm-smmu-v3: Don't unregister on shutdown
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-arm-smmu-v3-don-t-unregister-on-shutdown.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 32ea2c57dc216b6ad8125fa680d31daa5d421c95 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Date: Thu, 15 Dec 2022 16:12:51 +0200
Subject: iommu/arm-smmu-v3: Don't unregister on shutdown
From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
commit 32ea2c57dc216b6ad8125fa680d31daa5d421c95 upstream.
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@xxxxxxx>
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Link: https://lore.kernel.org/r/20221215141251.3688780-2-vladimir.oltean@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- 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
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[] = {
Patches currently in stable-queue which might be from vladimir.oltean@xxxxxxx are
queue-6.1/iommu-arm-smmu-don-t-unregister-on-shutdown.patch
queue-6.1/iommu-arm-smmu-v3-don-t-unregister-on-shutdown.patch
queue-6.1/iommu-arm-smmu-report-iommu_cap_cache_coherency-even-betterer.patch
