diff --git a/sys/fs/ptyfs/ptyfs_vnops.c b/sys/fs/ptyfs/ptyfs_vnops.c
index 88efa4f62646..ca7c7c27a3b6 100644
--- a/sys/fs/ptyfs/ptyfs_vnops.c
+++ b/sys/fs/ptyfs/ptyfs_vnops.c
@@ -691,7 +691,7 @@ ptyfs_readdir(void *v)
 		*ap->a_cookies = cookies;
 	}
 
-	for (; i < 2; i++) {
+	for (; i < 2 && uio->uio_resid >= UIO_MX; i++) {
 		/* `.' and/or `..' */
 		dp->d_fileno = PTYFS_FILENO(PTYFSroot, 0);
 		dp->d_namlen = i + 1;