The patch below does not apply to the 6.2-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.2.y git checkout FETCH_HEAD git cherry-pick -x 5a2f8d22ace4c8ac8798fab836dca7350fa710b1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023050717-related-online-6936@gregkh' --subject-prefix 'PATCH 6.2.y' HEAD^.. Possible dependencies: 5a2f8d22ace4 ("mm/hugetlb: fix uffd-wp during fork()") d0ce0e47b323 ("mm/hugetlb: convert hugetlb fault paths to use alloc_hugetlb_folio()") ea4c353df377 ("mm/hugetlb: convert hugetlb_install_page to folios") 0ffdc38eb564 ("mm/hugetlb: convert restore_reserve_on_error() to folios") e37d3e838d90 ("mm/hugetlb: convert alloc_migrate_huge_page to folios") ff7d853b0313 ("mm/hugetlb: increase use of folios in alloc_huge_page()") 3a740e8bb56e ("mm/hugetlb: convert alloc_surplus_huge_page() to folios") a36f1e902474 ("mm/hugetlb: convert dequeue_hugetlb_page functions to folios") 5b4bd90f9ac7 ("rmap: add folio parameter to __page_set_anon_rmap()") db4e5dbdcdd5 ("mm: use a folio in hugepage_add_anon_rmap() and hugepage_add_new_anon_rmap()") 4d510f3da4c2 ("mm: add folio_add_new_anon_rmap()") c7c3dec1c9db ("mm: rmap: remove lock_page_memcg()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5a2f8d22ace4c8ac8798fab836dca7350fa710b1 Mon Sep 17 00:00:00 2001 From: Peter Xu <peterx@xxxxxxxxxx> Date: Mon, 17 Apr 2023 15:53:12 -0400 Subject: [PATCH] mm/hugetlb: fix uffd-wp during fork() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "mm/hugetlb: More fixes around uffd-wp vs fork() / RO pins", v2. This patch (of 6): There're a bunch of things that were wrong: - Reading uffd-wp bit from a swap entry should use pte_swp_uffd_wp() rather than huge_pte_uffd_wp(). - When copying over a pte, we should drop uffd-wp bit when !EVENT_FORK (aka, when !userfaultfd_wp(dst_vma)). - When doing early CoW for private hugetlb (e.g. when the parent page was pinned), uffd-wp bit should be properly carried over if necessary. No bug reported probably because most people do not even care about these corner cases, but they are still bugs and can be exposed by the recent unit tests introduced, so fix all of them in one shot. Link: https://lkml.kernel.org/r/20230417195317.898696-1-peterx@xxxxxxxxxx Link: https://lkml.kernel.org/r/20230417195317.898696-2-peterx@xxxxxxxxxx Fixes: bc70fbf269fd ("mm/hugetlb: handle uffd-wp during fork()") Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> Cc: Mika Penttilä <mpenttil@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Nadav Amit <nadav.amit@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a08fb47fb200..d105b0b6a274 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4953,11 +4953,15 @@ static bool is_hugetlb_entry_hwpoisoned(pte_t pte) static void hugetlb_install_folio(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr, - struct folio *new_folio) + struct folio *new_folio, pte_t old) { + pte_t newpte = make_huge_pte(vma, &new_folio->page, 1); + __folio_mark_uptodate(new_folio); hugepage_add_new_anon_rmap(new_folio, vma, addr); - set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, &new_folio->page, 1)); + if (userfaultfd_wp(vma) && huge_pte_uffd_wp(old)) + newpte = huge_pte_mkuffd_wp(newpte); + set_huge_pte_at(vma->vm_mm, addr, ptep, newpte); hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm); folio_set_hugetlb_migratable(new_folio); } @@ -5032,14 +5036,12 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, */ ; } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) { - bool uffd_wp = huge_pte_uffd_wp(entry); - - if (!userfaultfd_wp(dst_vma) && uffd_wp) + if (!userfaultfd_wp(dst_vma)) entry = huge_pte_clear_uffd_wp(entry); set_huge_pte_at(dst, addr, dst_pte, entry); } else if (unlikely(is_hugetlb_entry_migration(entry))) { swp_entry_t swp_entry = pte_to_swp_entry(entry); - bool uffd_wp = huge_pte_uffd_wp(entry); + bool uffd_wp = pte_swp_uffd_wp(entry); if (!is_readable_migration_entry(swp_entry) && cow) { /* @@ -5050,10 +5052,10 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, swp_offset(swp_entry)); entry = swp_entry_to_pte(swp_entry); if (userfaultfd_wp(src_vma) && uffd_wp) - entry = huge_pte_mkuffd_wp(entry); + entry = pte_swp_mkuffd_wp(entry); set_huge_pte_at(src, addr, src_pte, entry); } - if (!userfaultfd_wp(dst_vma) && uffd_wp) + if (!userfaultfd_wp(dst_vma)) entry = huge_pte_clear_uffd_wp(entry); set_huge_pte_at(dst, addr, dst_pte, entry); } else if (unlikely(is_pte_marker(entry))) { @@ -5118,7 +5120,8 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, /* huge_ptep of dst_pte won't change as in child */ goto again; } - hugetlb_install_folio(dst_vma, dst_pte, addr, new_folio); + hugetlb_install_folio(dst_vma, dst_pte, addr, + new_folio, src_pte_old); spin_unlock(src_ptl); spin_unlock(dst_ptl); continue; @@ -5136,6 +5139,9 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, entry = huge_pte_wrprotect(entry); } + if (!userfaultfd_wp(dst_vma)) + entry = huge_pte_clear_uffd_wp(entry); + set_huge_pte_at(dst, addr, dst_pte, entry); hugetlb_count_add(npages, dst); }
