In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Fix WARN_ON in iommu probe path
Commit 1a75cc710b95 ("iommu/vt-d: Use rbtree to track iommu probed
devices") adds all devices probed by the iommu driver in a rbtree
indexed by the source ID of each device. It assumes that each device
has a unique source ID. This assumption is incorrect and the VT-d
spec doesn't state this requirement either.
The reason for using a rbtree to track devices is to look up the device
with PCI bus and devfunc in the paths of handling ATS invalidation time
out error and the PRI I/O page faults. Both are PCI ATS feature related.
Only track the devices that have PCI ATS capabilities in the rbtree to
avoid unnecessary WARN_ON in the iommu probe path. Otherwise, on some
platforms below kernel splat will be displayed and the iommu probe results
in failure.
