diff --git a/include/linux/mm.h b/include/linux/mm.h index be4457269a38..25e669632d2c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4654,11 +4654,25 @@ static inline int vm_fault_to_errno(vm_fault_t vm_fault, int foll_flags) /* * Indicates whether GUP can follow a PROT_NONE mapped page, or whether - * a (NUMA hinting) fault is required. + * a (NUMA hinting or userfaultfd RWP) fault is required. */ static inline bool gup_can_follow_protnone(const struct vm_area_struct *vma, unsigned int flags) { + /* + * VM_UFFD_RWP uses protnone as an access-tracking marker, not for + * NUMA hinting. GUP must always take a fault so the access is + * delivered to userfaultfd, regardless of FOLL_HONOR_NUMA_FAULT. + * + * Only do so while the VMA is accessible. If it has been made + * inaccessible (e.g. mprotect(PROT_NONE)), fall through to the guard + * below: forcing a fault there would loop, as handle_mm_fault() makes + * no progress on protnone in an inaccessible VMA, and the access is + * denied regardless of RWP anyway. + */ + if (vma_test_single_mask(vma, VMA_UFFD_RWP) && vma_is_accessible(vma)) + return false; + /* * If callers don't want to honor NUMA hinting faults, no need to * determine if we would actually have to trigger a NUMA hinting fault. diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 0b5fb0d0a0c1..55157567dc4c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1893,8 +1893,11 @@ static enum scan_result try_collapse_pte_mapped_thp(struct mm_struct *mm, unsign if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER)) return SCAN_VMA_CHECK; - /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */ - if (userfaultfd_wp(vma)) + /* + * Keep pmd pgtable while the uffd bit is in use; see comment in + * retract_page_tables(). + */ + if (userfaultfd_protected(vma)) return SCAN_PTE_UFFD; folio = filemap_lock_folio(vma->vm_file->f_mapping, @@ -2107,13 +2110,14 @@ static bool file_backed_vma_is_retractable(struct vm_area_struct *vma) return false; /* - * When a vma is registered with uffd-wp, we cannot recycle + * When a vma is registered with uffd-wp or RWP, we cannot recycle * the page table because there may be pte markers installed. - * Other vmas can still have the same file mapped hugely, but - * skip this one: it will always be mapped in small page size - * for uffd-wp registered ranges. + * VM_UFFD_RWP ranges similarly rely on per-PTE uffd state + * and cannot be recycled to a shared PMD. Other vmas can still + * have the same file mapped hugely, but skip this one: it will + * always be mapped in small page size for these registrations. */ - if (userfaultfd_wp(vma)) + if (userfaultfd_protected(vma)) return false; /* diff --git a/mm/rmap.c b/mm/rmap.c index 50f973b63f1c..26166a6b8cb9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1965,7 +1965,7 @@ static inline unsigned int folio_unmap_pte_batch(struct folio *folio, if (pte_unused(pte)) return 1; - if (userfaultfd_wp(vma)) + if (userfaultfd_protected(vma)) return 1; /*