If uffd fills the zeropage or installs to COW-ed PTE, break it first. Signed-off-by: Chih-En Lin <shiyn.lin@xxxxxxxxx> --- mm/userfaultfd.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 53c3d916ff66..f5e0a97d6a3d 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -70,6 +70,9 @@ int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, struct inode *inode; pgoff_t offset, max_off; + if (break_cow_pte(dst_vma, dst_pmd, dst_addr)) + return -ENOMEM; + _dst_pte = mk_pte(page, dst_vma->vm_page_prot); _dst_pte = pte_mkdirty(_dst_pte); if (page_in_cache && !vm_shared) @@ -215,6 +218,9 @@ static int mfill_zeropage_pte(struct mm_struct *dst_mm, pgoff_t offset, max_off; struct inode *inode; + if (break_cow_pte(dst_vma, dst_pmd, dst_addr)) + return -ENOMEM; + _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), dst_vma->vm_page_prot)); dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); -- 2.34.1
