CVE-2026-90388: In the Linux kernel, the following vulnerability has been resolved: iommu/dma: Check atomic pool allocation result dire

In the Linux kernel, the following vulnerability has been resolved:

iommu/dma: Check atomic pool allocation result directly

The non-blocking, non-coherent allocation path uses dma_alloc_from_pool(), which returns the allocated page and fills cpu_addr only on success.

Do not rely on cpu_addr to detect allocation failure in this path. Check the returned page directly before using it for the IOMMU mapping.