In the Linux kernel, the following vulnerability has been resolved: iommu: Handle unmap error when iommu_debug is enabled Sashiko noticed a latent bug where the map error flow called iommu_unmap() which calls iommu_debug_unmap_begin()/iommu_debug_unmap_end() however since this is an error path the map flow never actually established the original iommu_debug_map() it will malfunction. Lift the unmap error handling into iommu_map_nosync() and reorder it so the trace_map()/iommu_debug_map() records the partial mapping and then immediately unmaps it. This avoid creating the unbalanced tracking and provides saner tracing instead of a unmap unmatched to any map.
https://git.kernel.org/stable/c/0cd028806efc148a75d4acf711d21db335a89661
https://git.kernel.org/stable/c/0735c54804c709d1b292f3b6947cfb560b2ce552