@@ -2427,10 +2427,17 @@ again:
entry = make_migration_entry(page, mpfn &
MIGRATE_PFN_WRITE);
swp_pte = swp_entry_to_pte(entry);
- if (pte_soft_dirty(pte))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_uffd_wp(pte))
- swp_pte = pte_swp_mkuffd_wp(swp_pte);
+ if (pte_present(pte)) {
+ if (pte_soft_dirty(pte))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_uffd_wp(pte))
+ swp_pte = pte_swp_mkuffd_wp(swp_pte);
+ } else {
+ if (pte_swp_soft_dirty(pte))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_swp_uffd_wp(pte))
+ swp_pte = pte_swp_mkuffd_wp(swp_pte);
+ }
set_pte_at(mm, addr, ptep, swp_pte);
/*
@@ -1511,9 +1511,14 @@ static bool try_to_unmap_one(struct page
*/
entry = make_migration_entry(page, 0);
swp_pte = swp_entry_to_pte(entry);
- if (pte_soft_dirty(pteval))
+
+ /*
+ * pteval maps a zone device page and is therefore
+ * a swap pte.
+ */
+ if (pte_swp_soft_dirty(pteval))
swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_uffd_wp(pteval))
+ if (pte_swp_uffd_wp(pteval))
swp_pte = pte_swp_mkuffd_wp(swp_pte);
set_pte_at(mm, pvmw.address, pvmw.pte, swp_pte);
/*
The patch titled Subject: mm/rmap: fixup copying of soft dirty and uffd ptes has been added to the -mm tree. Its filename is mm-rmap-fixup-copying-of-soft-dirty-and-uffd-ptes.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-fixup-copying-of-soft-dirty-and-uffd-ptes.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-fixup-copying-of-soft-dirty-and-uffd-ptes.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Alistair Popple <alistair@popple.id.au> Subject: mm/rmap: fixup copying of soft dirty and uffd ptes 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. Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au Fixes: a5430dda8a3a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration") Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages") Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration") Signed-off-by: Alistair Popple <alistair@popple.id.au> 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> Cc: Alistair Popple <alistair@popple.id.au> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/migrate.c | 15 +++++++++++---- mm/rmap.c | 9 +++++++-- 2 files changed, 18 insertions(+), 6 deletions(-)