Re: [PATCH] mm/huge_memory: fix override of entry in remove_migration_pmd

[Balbir Singh <balbirs@nvidia.com>]

On 11/14/25 12:21, Balbir Singh wrote:
> Recent changes exposed a BUG in remove_migration_pmd() where the
> migration entry was being overridden when the folio is device private.
> 
> Use scope local entry for creating the device private pmde. Make the
> pmde writable if the migration entry is writable by moving the check
> is_migration_write() prior to creating the device private entry.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
> Cc: Rakie Kim <rakie.kim@sk.com>
> Cc: Byungchul Park <byungchul@sk.com>
> Cc: Gregory Price <gourry@gourry.net>
> Cc: Ying Huang <ying.huang@linux.alibaba.com>
> Cc: Alistair Popple <apopple@nvidia.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
> Cc: Nico Pache <npache@redhat.com>
> Cc: Ryan Roberts <ryan.roberts@arm.com>
> Cc: Dev Jain <dev.jain@arm.com>
> Cc: Barry Song <baohua@kernel.org>
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Danilo Krummrich <dakr@kernel.org>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Simona Vetter <simona@ffwll.ch>
> Cc: Ralph Campbell <rcampbell@nvidia.com>
> Cc: Mika Penttilä <mpenttil@redhat.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Francois Dugast <francois.dugast@intel.com>
> 
> Signed-off-by: Balbir Singh <balbirs@nvidia.com>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
>  mm/huge_memory.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 

Hi, Andrew

This patch fixes a bug in mm/rmap: extend rmap and migration support device-private entries
in the thp device-private series.

Thanks,
Balbir