From: Alistair Popple <alistair@xxxxxxxxxxxx>
Subject: mm/migrate: fixup setting UFFD_WP flag
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.
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@xxxxxxxxxxxx
Fixes: f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@xxxxxxxxxxxx>
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/migrate.c~mm-migrate-fixup-setting-uffd_wp-flag
+++ a/mm/migrate.c
@@ -251,7 +251,7 @@ static bool remove_migration_pte(struct
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);
}
}
_
