diff options
| -rw-r--r-- | mm/userfaultfd.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index e54e5c8907fa..290b2a0d84ac 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -787,21 +787,23 @@ retry: } dst_pmdval = pmdp_get_lockless(dst_pmd); - /* - * If the dst_pmd is mapped as THP don't - * override it and just be strict. - */ - if (unlikely(pmd_trans_huge(dst_pmdval))) { - err = -EEXIST; - break; - } if (unlikely(pmd_none(dst_pmdval)) && unlikely(__pte_alloc(dst_mm, dst_pmd))) { err = -ENOMEM; break; } - /* If an huge pmd materialized from under us fail */ - if (unlikely(pmd_trans_huge(*dst_pmd))) { + dst_pmdval = pmdp_get_lockless(dst_pmd); + /* + * If the dst_pmd is THP don't override it and just be strict. + * (This includes the case where the PMD used to be THP and + * changed back to none after __pte_alloc().) + */ + if (unlikely(!pmd_present(dst_pmdval) || pmd_trans_huge(dst_pmdval) || + pmd_devmap(dst_pmdval))) { + err = -EEXIST; + break; + } + if (unlikely(pmd_bad(dst_pmdval))) { err = -EFAULT; break; } |