diff options
Diffstat (limited to 'mm/ksm.c')
| -rw-r--r-- | mm/ksm.c | 11 |
1 files changed, 11 insertions, 0 deletions
@@ -1095,6 +1095,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page, goto out_unlock; } + /* See page_try_share_anon_rmap(): clear PTE first. */ if (anon_exclusive && page_try_share_anon_rmap(page)) { set_pte_at(mm, pvmw.address, pvmw.pte, entry); goto out_unlock; @@ -1134,6 +1135,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, { struct mm_struct *mm = vma->vm_mm; pmd_t *pmd; + pmd_t pmde; pte_t *ptep; pte_t newpte; spinlock_t *ptl; @@ -1148,6 +1150,15 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, pmd = mm_find_pmd(mm, addr); if (!pmd) goto out; + /* + * Some THP functions use the sequence pmdp_huge_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 = *pmd; + barrier(); + if (!pmd_present(pmde) || pmd_trans_huge(pmde)) + goto out; mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, addr, addr + PAGE_SIZE); |