Subject: verify pmd_trans_huge isn't leaking From: Andrea Arcangeli pte_trans_huge must not leak in certain vmas like the mmio special pfn or filebacked mappings. Signed-off-by: Andrea Arcangeli Acked-by: Rik van Riel --- diff --git a/mm/memory.c b/mm/memory.c --- a/mm/memory.c +++ b/mm/memory.c @@ -1420,6 +1420,7 @@ int __get_user_pages(struct task_struct pmd = pmd_offset(pud, pg); if (pmd_none(*pmd)) return i ? : -EFAULT; + VM_BUG_ON(pmd_trans_huge(*pmd)); pte = pte_offset_map(pmd, pg); if (pte_none(*pte)) { pte_unmap(pte); @@ -1621,8 +1622,10 @@ pte_t *get_locked_pte(struct mm_struct * pud_t * pud = pud_alloc(mm, pgd, addr); if (pud) { pmd_t * pmd = pmd_alloc(mm, pud, addr); - if (pmd) + if (pmd) { + VM_BUG_ON(pmd_trans_huge(*pmd)); return pte_alloc_map_lock(mm, pmd, addr, ptl); + } } return NULL; } @@ -1841,6 +1844,7 @@ static inline int remap_pmd_range(struct pmd = pmd_alloc(mm, pud, addr); if (!pmd) return -ENOMEM; + VM_BUG_ON(pmd_trans_huge(*pmd)); do { next = pmd_addr_end(addr, end); if (remap_pte_range(mm, pmd, addr, next, @@ -3316,6 +3320,7 @@ static int follow_pte(struct mm_struct * goto out; pmd = pmd_offset(pud, address); + VM_BUG_ON(pmd_trans_huge(*pmd)); if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) goto out;