Re: [PATCH v2 1/2] fs/proc/task_mmu: do not warn on seeing non-migration pmd entry

[Lorenzo Stoakes <ljs@kernel.org>]

On Sat, May 30, 2026 at 08:54:11AM +0000, Dev Jain wrote:
> pagemap_pmd_range_thp() warns if a non-present PMD is not a migration
> entry. This became false once device-private entries at the PMD level were
> added.
>
> Therefore, remove the stale migration-only assertion.
>
> Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
> Cc: stable@vger.kernel.org
> Signed-off-by: Dev Jain <dev.jain@arm.com>

LGTM so:

Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>

I also verified that I could trigger this locally with your test, so feel free
to add:

Tested-by: Lorenzo Stoakes <ljs@kernel.org>

Cheers, Lorenzo

> ---
>  fs/proc/task_mmu.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 1e3a15bf46f4e..58938e62154d9 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -2129,7 +2129,6 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
>  			flags |= PM_SOFT_DIRTY;
>  		if (pmd_swp_uffd_wp(pmd))
>  			flags |= PM_UFFD_WP;
> -		VM_WARN_ON_ONCE(!pmd_is_migration_entry(pmd));
>  		page = softleaf_to_page(entry);
>  	}
>
> --
> 2.43.0
>