[PATCH 1/2] mm/migrate: Fixup setting UFFD_WP flag

[Alistair Popple]

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 <alist...@popple.id.au>
Cc: sta...@vger.kernel.org
---
 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);
                        }
                }
 
-- 
2.20.1