mm/migrate: fixup setting UFFD_WP flag

Commit f45ec5ff16 ("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: f45ec5ff16 ("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>
This commit is contained in:
Alistair Popple 2020-09-04 16:35:58 -07:00 committed by Linus Torvalds
parent 7867fd7cc4
commit ebdf8321ee

View File

@ -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);
}
}