diff options
authorAlistair Popple <alistair@popple.id.au>2020-09-04 16:36:01 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-09-09 19:14:32 +0200
commita8bf40a7538fbc9652457506fc3e5ca5c3228732 (patch)
parent9b4a9e89f6e87516edd5e5a610abe15d1cad5ec9 (diff)
mm/rmap: fixup copying of soft dirty and uffd ptes
commit ad7df764b7e1c7dc64e016da7ada2e3e1bb90700 upstream. 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: 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> 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> Cc: Alistair Popple <alistair@popple.id.au> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 18 insertions, 6 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 40cd7016ae6f..6a9ffe887e91 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2330,10 +2330,17 @@ again:
entry = make_migration_entry(page, mpfn &
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);
diff --git a/mm/rmap.c b/mm/rmap.c
index 6cce9ef06753..536f2706a6c8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1511,9 +1511,14 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
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);