From: Peter Xu <pet...@redhat.com> UFFD_EVENT_FORK support for uffd-wp should be already there, except that we should clean the uffd-wp bit if uffd fork event is not enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA is not being tracked by VM_UFFD_WP. Do this for both small PTEs and huge PMDs.
Signed-off-by: Peter Xu <pet...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Reviewed-by: Jerome Glisse <jgli...@redhat.com> Reviewed-by: Mike Rapoport <r...@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Bobby Powers <bobbypow...@gmail.com> Cc: Brian Geffon <bgef...@google.com> Cc: David Hildenbrand <da...@redhat.com> Cc: Denis Plotnikov <dplotni...@virtuozzo.com> Cc: "Dr . David Alan Gilbert" <dgilb...@redhat.com> Cc: Hugh Dickins <hu...@google.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: "Kirill A . Shutemov" <kir...@shutemov.name> Cc: Martin Cracauer <craca...@cons.org> Cc: Marty McFadden <mcfadd...@llnl.gov> Cc: Maya Gokhale <gokha...@llnl.gov> Cc: Mel Gorman <mgor...@suse.de> Cc: Mike Kravetz <mike.krav...@oracle.com> Cc: Pavel Emelyanov <xe...@openvz.org> Cc: Rik van Riel <r...@redhat.com> Cc: Shaohua Li <s...@fb.com> Link: http://lkml.kernel.org/r/20200220163112.11409-9-pet...@redhat.com Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-102938 (cherry picked from commit b569a1760782f3da03ff718d61f74163dea599ff) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/huge_memory.c | 8 ++++++++ mm/memory.c | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index be580b411a6a..b26c2daf3547 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -921,6 +921,14 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, ret = -EAGAIN; pmd = *src_pmd; + /* + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA + * does not have the VM_UFFD_WP, which means that the uffd + * fork event is not enabled. + */ + if (!(vma->vm_flags & VM_UFFD_WP)) + pmd = pmd_clear_uffd_wp(pmd); + #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION if (unlikely(is_swap_pmd(pmd))) { swp_entry_t entry = pmd_to_swp_entry(pmd); diff --git a/mm/memory.c b/mm/memory.c index dc267ae5b293..7e0189d729e3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1037,6 +1037,14 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte = pte_mkclean(pte); pte = pte_mkold(pte); + /* + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA + * does not have the VM_UFFD_WP, which means that the uffd + * fork event is not enabled. + */ + if (!(vm_flags & VM_UFFD_WP)) + pte = pte_clear_uffd_wp(pte); + page = vm_normal_page(vma, addr, pte); if (page) { get_page(page); -- 2.25.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
