On Thursday, 27 January 2022 2:09:41 PM AEDT Alex Sierra wrote:
[...]
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 277562cd4cf5..2b3375e165b1 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2340,8 +2340,6 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> if (is_writable_device_private_entry(entry))
> mpfn |= MIGRATE_PFN_WRITE;
> } else {
> - if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> - goto next;
This isn't correct as it allows zero pfn pages to be selected for migration
when they shouldn't be (ie. because MIGRATE_VMA_SELECT_SYSTEM isn't specified).
> pfn = pte_pfn(pte);
> if (is_zero_pfn(pfn)) {
> mpfn = MIGRATE_PFN_MIGRATE;
> @@ -2349,6 +2347,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> goto next;
> }
> page = vm_normal_page(migrate->vma, addr, pte);
> + if (page && !is_zone_device_page(page) &&
> + !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> + goto next;
> + if (page && is_device_coherent_page(page) &&
> + (!(migrate->flags &
> MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> + page->pgmap->owner != migrate->pgmap_owner))
> + goto next;
> mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
> mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
> }
>
