Re: [PATCH 7.2.y] iommu/arm-smmu-v3: Disable implementations during devm teardown

[Nicolin Chen <nicolinc@nvidia.com>]

On Thu, Sep 10, 2026 at 02:54:29PM +0800, Wentao Guan wrote:
> The Tegra241 CMDQV teardown fix moved VINTF hardware deinitialization
> into the implementation device_disable() callback. However, its stable
> backport preceded the conversion to devm teardown and could only invoke
> the callback from the shutdown path.

Hmm, it did...

[correct in mainline]
git log --oneline v7.3-rc1 drivers/iommu/arm/arm-smmu-v3/
...
9ff145a25c5c8 iommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown
2bd22a0d40503 iommu/arm-smmu-v3: Manage teardown with devm
...

[inverted in two trees]
git log --oneline v7.2.5 drivers/iommu/arm/arm-smmu-v3/
...
78fd5a2d65f35 iommu/arm-smmu-v3: Manage teardown with devm
f9b7375db3b36 iommu/arm-smmu-v3: Add HAFT support for SVA
5994617e09ee6 iommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown
...

git log --oneline v6.18.51 drivers/iommu/arm/arm-smmu-v3/
...
2235eafda9b3d iommu/arm-smmu-v3: Manage teardown with devm
d903d99ffd22b iommu/tegra241-cmdqv: Reject a vSID wider than the SID_MATCH field
d2ab08437e913 iommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown
...

[missing cmdqv fix]
git log --oneline v6.12.109 -33 drivers/iommu/arm/arm-smmu-v3/
...
981686f413776 iommu/arm-smmu-v3: Manage teardown with devm
...

Patch itself looks good to me for v7.2 stable and v6.8 longterm.

But v6.12 longterm might need some extra fix, Sasha?

> Now that arm_smmu_disable_action() manages normal teardown, invoke the
> implementation callback there while the command queue is still alive.
> This prevents the subsequent implementation remove action from releasing
> resources while the CMDQV hardware remains active.
> 
> After ("iommu/arm-smmu-v3: Manage teardown with devm") merged in stable,
> now keep the shutdown path consistent with mainline, where disabling
> the base SMMU is sufficient.
> 
> It is a fix for stable tree commit to aligned with mainline, so no
> upstream commit id here.
>
> Fixes: 5994617e09ee ("iommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown")
> Signed-off-by: Wentao Guan <guanwentao@uniontech.com>

Acked-by: Nicolin Chen <nicolinc@nvidia.com>