diff --git a/mm/rmap.c b/mm/rmap.c
index e5dfe2ae6b0d..003377e24232 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1475,7 +1475,15 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			/*
 			 * No need to invalidate here it will synchronize on
 			 * against the special swap migration pte.
+			 *
+			 * The assignment to subpage above was computed from a
+			 * swap PTE which results in an invalid pointer.
+			 * Since only PAGE_SIZE pages can currently be
+			 * migrated, just set it to page. This will need to be
+			 * changed when hugepage migrations to device private
+			 * memory are supported.
 			 */
+			subpage = page;
 			goto discard;
 		}