pgd_t *pgd;
pud_t *pud;
pmd_t *pmd = NULL;
+ pmd_t pmde;
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
goto out;
pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
+ /*
+ * Some THP functions use the sequence pmdp_clear_flush(), set_pmd_at()
+ * without holding anon_vma lock for write. So when looking for a
+ * genuine pmde (in which to find pte), test present and !THP together.
+ */
+ pmde = ACCESS_ONCE(*pmd);
+ if (!pmd_present(pmde) || pmd_trans_huge(pmde))
pmd = NULL;
out:
return pmd;
if (!pmd)
return NULL;
- if (pmd_trans_huge(*pmd))
- return NULL;
-
pte = pte_offset_map(pmd, address);
/* Make a quick check before getting the lock */
if (!sync && !pte_present(*pte)) {