Re: [PATCH v6 1/5] mm/zone_device: Reinitialize large zone device private folios

Matthew Brost
2026-01-16T22:37:11Z

On Fri, Jan 16, 2026 at 02:34:32PM -0800, Andrew Morton wrote:
> On Fri, 16 Jan 2026 12:10:16 +0100 Francois Dugast <francois.dugast@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.
> >
> > Without this fix, individual pages could have invalid pgmap fields and
> > flags (with PG_locked being notably problematic) due to prior different
> > order allocations, which can, and will, result in kernel crashes.
>
> Is it OK to leave 6.18.x without this fixed?

I think 6.18.x is fine, the offending patch + large device pages is
going into 6.19, right?

Matt