diff --git a/mm/shmem.c b/mm/shmem.c index 99d5867daadb..16a3d7044c52 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2274,6 +2274,16 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, _dst_pte = mk_pte(page, dst_vma->vm_page_prot); if (dst_vma->vm_flags & VM_WRITE) _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte)); + else { + /* + * We don't set the pte dirty if the vma has no + * VM_WRITE permission, so mark the page dirty or it + * could be freed from under us. We could do it + * unconditionally before unlock_page(), but doing it + * only if VM_WRITE is not set is faster. + */ + set_page_dirty(page); + } dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); @@ -2307,6 +2317,7 @@ out: return ret; out_release_uncharge_unlock: pte_unmap_unlock(dst_pte, ptl); + ClearPageDirty(page); delete_from_page_cache(page); out_release_uncharge: mem_cgroup_cancel_charge(page, memcg, false);