The patch titled Subject: mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare has been removed from the -mm tree. Its filename was mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------ From: Peter Xu peterx@redhat.com Subject: mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare
I found it by pure code review, that pte_same_as_swp() of unuse_vma() didn't take uffd-wp bit into account when comparing ptes. pte_same_as_swp() returning false negative could cause failure to swapoff swap ptes that was wr-protected by userfaultfd.
Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration") Signed-off-by: Peter Xu peterx@redhat.com Acked-by: Hugh Dickins hughd@google.com Cc: Andrea Arcangeli aarcange@redhat.com Cc: stable@vger.kernel.org [5.7+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
include/linux/swapops.h | 15 +++++++++++---- mm/swapfile.c | 2 +- 2 files changed, 12 insertions(+), 5 deletions(-)
--- a/include/linux/swapops.h~mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare +++ a/include/linux/swapops.h @@ -23,6 +23,16 @@ #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT) #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
+/* Clear all flags but only keep swp_entry_t related information */ +static inline pte_t pte_swp_clear_flags(pte_t pte) +{ + if (pte_swp_soft_dirty(pte)) + pte = pte_swp_clear_soft_dirty(pte); + if (pte_swp_uffd_wp(pte)) + pte = pte_swp_clear_uffd_wp(pte); + return pte; +} + /* * Store a type+offset into a swp_entry_t in an arch-independent format */ @@ -66,10 +76,7 @@ static inline swp_entry_t pte_to_swp_ent { swp_entry_t arch_entry;
- if (pte_swp_soft_dirty(pte)) - pte = pte_swp_clear_soft_dirty(pte); - if (pte_swp_uffd_wp(pte)) - pte = pte_swp_clear_uffd_wp(pte); + pte = pte_swp_clear_flags(pte); arch_entry = __pte_to_swp_entry(pte); return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); } --- a/mm/swapfile.c~mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare +++ a/mm/swapfile.c @@ -1900,7 +1900,7 @@ unsigned int count_swap_pages(int type,
static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte) { - return pte_same(pte_swp_clear_soft_dirty(pte), swp_pte); + return pte_same(pte_swp_clear_flags(pte), swp_pte); }
/* _
Patches currently in -mm which might be from peterx@redhat.com are
mm-gup_benchmark-support-threading.patch mm-gup-pack-has_pinned-in-mmf_has_pinned-fix.patch userfaultfd-selftests-use-user-mode-only.patch userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch userfaultfd-selftests-dropping-verify-check-in-locking_thread.patch userfaultfd-selftests-only-dump-counts-if-mode-enabled.patch userfaultfd-selftests-unify-error-handling.patch mm-thp-simplify-copying-of-huge-zero-page-pmd-when-fork.patch mm-userfaultfd-fix-uffd-wp-special-cases-for-fork.patch mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch mm-userfaultfd-fail-uffd-wp-registeration-if-not-supported.patch mm-pagemap-export-uffd-wp-protection-information.patch userfaultfd-selftests-add-pagemap-uffd-wp-test.patch userfaultfd-selftests-reinitialize-test-context-in-each-test-fix.patch