diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index a589935bf302..896760bad455 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -49,11 +49,19 @@ size_t copy_from_user_iter(void __user *iter_from, size_t progress,
 
 	if (should_fail_usercopy())
 		return len;
-	if (can_do_masked_user_access())
+	if (can_do_masked_user_access()) {
 		iter_from = mask_user_address(iter_from);
-	else if (!access_ok(iter_from, len))
-		return res;
+	} else {
+		if (!access_ok(iter_from, len))
+			return res;
 
+		/*
+		 * Ensure that bad access_ok() speculation will not
+		 * lead to nasty side effects *after* the copy is
+		 * finished:
+		 */
+		barrier_nospec();
+	}
 	to += progress;
 	instrument_copy_from_user_before(to, iter_from, len);
 	res = raw_copy_from_user(to, iter_from, len);