diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/mm/memory.c b/mm/memory.c index aad226daf41b..3e836fecd035 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -828,12 +828,8 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, return -EBUSY; return -ENOENT; } else if (is_pte_marker_entry(entry)) { - /* - * We're copying the pgtable should only because dst_vma has - * uffd-wp enabled, do sanity check. - */ - WARN_ON_ONCE(!userfaultfd_wp(dst_vma)); - set_pte_at(dst_mm, addr, dst_pte, pte); + if (is_swapin_error_entry(entry) || userfaultfd_wp(dst_vma)) + set_pte_at(dst_mm, addr, dst_pte, pte); return 0; } if (!userfaultfd_wp(dst_vma)) @@ -3629,8 +3625,12 @@ static vm_fault_t pte_marker_clear(struct vm_fault *vmf) /* * Be careful so that we will only recover a special uffd-wp pte into a * none pte. Otherwise it means the pte could have changed, so retry. + * + * This should also cover the case where e.g. the pte changed + * quickly from a PTE_MARKER_UFFD_WP into PTE_MARKER_SWAPIN_ERROR. + * So is_pte_marker() check is not enough to safely drop the pte. */ - if (is_pte_marker(*vmf->pte)) + if (pte_same(vmf->orig_pte, *vmf->pte)) pte_clear(vmf->vma->vm_mm, vmf->address, vmf->pte); pte_unmap_unlock(vmf->pte, vmf->ptl); return 0; |