6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
[ Upstream commit 89e8a2366e3bce584b6c01549d5019c5cda1205e ]
iommu_sva_bind_device() should return either a sva bond handle or an
ERR_PTR value in error cases. Existing drivers (idxd and uacce) only
check the return value with IS_ERR(). This could potentially lead to
a kernel NULL pointer dereference issue if the function returns NULL
instead of an error pointer.
In reality, this doesn't cause any problems because iommu_sva_bind_device()
only returns NULL when the kernel is not configured with CONFIG_IOMMU_SVA.
In this case, iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) will
return an error, and the device drivers won't call iommu_sva_bind_device()
at all.
Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices")
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Vasant Hegde <vasant.hegde@xxxxxxx>
Link: https://lore.kernel.org/r/20240528042528.71396-1-baolu.lu@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/linux/iommu.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2e925b5eba534..3b67d59a36bf9 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -1537,7 +1537,7 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
static inline struct iommu_sva *
iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
{
- return NULL;
+ return ERR_PTR(-ENODEV);
}
static inline void iommu_sva_unbind_device(struct iommu_sva *handle)
--
2.43.0
