Re: [PATCH 1/2] iommu/tegra: Add support for struct iommu_device

Joerg Roedel
2017-08-30T12:09:03Z

Hi Jon,

On Wed, Aug 30, 2017 at 12:04:38PM +0100, Jon Hunter wrote:
> With next-20170829 I am seeing several Tegra boards crashing [0][1] on
> boot in tegra_smmu_probe() and the bisect is point to this commit. Looks
> like there maybe a sequence problem between calls to bus_set_iommu() and
> iommu_device_add_sysfs() which results in a NULL pointer dereference.

Thanks for the report. Can you please test whether the patch below
fixes the problem?

Thanks,

Joerg

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 2802e12e6a54..48ffbe95a663 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -949,10 +949,6 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,

tegra_smmu_ahb_enable();

- err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
- if (err < 0)
- return ERR_PTR(err);
-
err = iommu_device_sysfs_add(&smmu->iommu, dev, NULL, dev_name(dev));
if (err)
return ERR_PTR(err);
@@ -965,6 +961,10 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
return ERR_PTR(err);
}

+ err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
+ if (err < 0)
+ return ERR_PTR(err);
+
if (IS_ENABLED(CONFIG_DEBUG_FS))
tegra_smmu_debugfs_init(smmu);