On Mon, Aug 24, 2020 at 06:31:27PM +1000, Alistair Popple wrote:
> Commit f45ec5ff16a75 ("userfaultfd: wp: support swap and page
> migration") introduced support for tracking the uffd wp bit during page
> migration. However the non-swap PTE variant was used to set the flag for
> zone device private pages which are a type of swap page.
>
> This leads to corruption of the swap offset if the original PTE has the
> uffd_wp flag set.
>
> Fixes: f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
> Signed-off-by: Alistair Popple <alistair@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> mm/migrate.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 34a842a8eb6a..ddb64253fe3e 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -251,7 +251,7 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
> entry = make_device_private_entry(new, pte_write(pte));
> pte = swp_entry_to_pte(entry);
> if (pte_swp_uffd_wp(*pvmw.pte))
> - pte = pte_mkuffd_wp(pte);
> + pte = pte_swp_mkuffd_wp(pte);
> }
> }
Looks correct... thanks!
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
--
Peter Xu
