Executive brief
In the Linux kernel, the following vulnerability has been resolved:
drm/pagemap: dma-unmap pages before handling migration errors
drm_pagemap_migrate_unmap_pages() relies on the pages array to determine which pages require DMA unmapping. However, drm_pagemap_migration_unlock_put_pages() clears the array as part of its cleanup, leaving drm_pagemap_migrate_unmap_pages() with no valid page information if it is called afterward.
Call drm_pagemap_migrate_unmap_pages() before drm_pagemap_migration_unlock_put_pages() so the pages array remains valid during DMA unmapping.