CVE-2026-89804

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 page_size()

and records that length in dma_info->size. For a compound folio

page_size() is PAGE_SIZE << order, but two teardown sites still pass a

literal PAGE_SIZE to dma_unmap_page():

- nouveau_dmem_migrate_to_ram() on the success path, and

- nouveau_dmem_migrate_copy_one() 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

nouveau_dmem_migrate_chunk() and nouveau_dmem_evict_chunk(), already

use the saved size; use it here too.