UBUNTU-CVE-2026-89804: High severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau/dmem: fix mismatched DMA unmap size for large folios Device-private THP migration maps migration buffers with pagesize() and records that length in dmainfo->size. For a compound folio pagesize() is PAGESIZE << order, but two teardown sites still pass a literal PAGESIZE to dmaunmappage(): - nouveaudmemmigratetoram() on the success path, and - nouveaudmemmigratecopyone() on the copy-error path. For an order > 0 folio this unmaps less than was mapped, leaking the remainder of the IOMMU/IOVA mapping. The other unmap sites, in nouveaudmemmigratechunk() and nouveaudmemevictchunk(), already use the saved size; use it here too.