• Alistair Popple's avatar
    mm/rmap: fixup copying of soft dirty and uffd ptes · ad7df764
    Alistair Popple authored
    During memory migration a pte is temporarily replaced with a migration
    swap pte.  Some pte bits from the existing mapping such as the soft-dirty
    and uffd write-protect bits are preserved by copying these to the
    temporary migration swap pte.
    
    However these bits are not stored at the same location for swap and
    non-swap ptes.  Therefore testing these bits requires using the
    appropriate helper function for the given pte type.
    
    Unfortunately several code locations were found where the wrong helper
    function is being used to test soft_dirty and uffd_wp bits which leads to
    them getting incorrectly set or cleared during page-migration.
    
    Fix these by using the correct tests based on pte type.
    
    Fixes: a5430dda ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
    Fixes: 8c3328f1 ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
    Fixes: f45ec5ff ("userfaultfd: wp: support swap and page migration")
    Signed-off-by: default avatarAlistair Popple <alistair@popple.id.au>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
    Cc: Jérôme Glisse <jglisse@redhat.com>
    Cc: John Hubbard <jhubbard@nvidia.com>
    Cc: Ralph Campbell <rcampbell@nvidia.com>
    Cc: Alistair Popple <alistair@popple.id.au>
    Cc: <stable@vger.kernel.org>
    Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.auSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    ad7df764
rmap.c 55.6 KB