[PATCH v5 1/5] mm/zone_device: Reinitialize large zone device private folios

[Andrew Morton]

On Wed, 14 Jan 2026 20:19:52 +0100 Francois Dugast <francois.dugast at intel.com> wrote:

> Reinitialize metadata for large zone device private folios in
> zone_device_page_init prior to creating a higher-order zone device
> private folio. This step is necessary when the folio’s order changes
> dynamically between zone_device_page_init calls to avoid building a
> corrupt folio. As part of the metadata reinitialization, the dev_pagemap
> must be passed in from the caller because the pgmap stored in the folio
> page may have been overwritten with a compound head.

Thanks.  What are the worst-case userspace-visible effects of the bug?