From: Alistair Popple alistair@popple.id.au
commit ebdf8321eeeb623aed60f7ed16f7445363230118 upstream.
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@popple.id.au Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: Peter Xu peterx@redhat.com Cc: Jérôme Glisse jglisse@redhat.com Cc: John Hubbard jhubbard@nvidia.com Cc: Ralph Campbell rcampbell@nvidia.com Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/migrate.c +++ b/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); } }