diff options
Diffstat (limited to 'mm/userfaultfd.c')
| -rw-r--r-- | mm/userfaultfd.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 00122f42718c..cc4ce205bbec 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -178,6 +178,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, spinlock_t *ptl; struct folio *folio = page_folio(page); bool page_in_cache = folio_mapping(folio); + pte_t dst_ptep; _dst_pte = mk_pte(page, dst_vma->vm_page_prot); _dst_pte = pte_mkdirty(_dst_pte); @@ -199,12 +200,15 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, } ret = -EEXIST; + + dst_ptep = ptep_get(dst_pte); + /* - * We allow to overwrite a pte marker: consider when both MISSING|WP - * registered, we firstly wr-protect a none pte which has no page cache - * page backing it, then access the page. + * We are allowed to overwrite a UFFD pte marker: consider when both + * MISSING|WP registered, we firstly wr-protect a none pte which has no + * page cache page backing it, then access the page. */ - if (!pte_none_mostly(ptep_get(dst_pte))) + if (!pte_none(dst_ptep) && !is_uffd_pte_marker(dst_ptep)) goto out_unlock; if (page_in_cache) { @@ -583,12 +587,15 @@ retry: goto out_unlock; } - if (!uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE) && - !huge_pte_none_mostly(huge_ptep_get(dst_mm, dst_addr, dst_pte))) { - err = -EEXIST; - hugetlb_vma_unlock_read(dst_vma); - mutex_unlock(&hugetlb_fault_mutex_table[hash]); - goto out_unlock; + if (!uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE)) { + const pte_t ptep = huge_ptep_get(dst_mm, dst_addr, dst_pte); + + if (!huge_pte_none(ptep) && !is_uffd_pte_marker(ptep)) { + err = -EEXIST; + hugetlb_vma_unlock_read(dst_vma); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + goto out_unlock; + } } err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, dst_addr, |