diff --git a/pkgs/racket-test-core/tests/racket/port.rktl b/pkgs/racket-test-core/tests/racket/port.rktl
index c113b4e319..1d84f275a9 100644
--- a/pkgs/racket-test-core/tests/racket/port.rktl
+++ b/pkgs/racket-test-core/tests/racket/port.rktl
@@ -887,6 +887,9 @@
 
   (define ofile (open-output-file path #:mode 'text #:exists 'replace))
   (fprintf ofile "abc\ndef\nghi\n")
+  (test 'block file-stream-buffer-mode ofile)
+  (test (void) file-stream-buffer-mode ofile 'line)
+  (test 'line file-stream-buffer-mode ofile)
   (close-output-port ofile)
 
   (let ()
diff --git a/racket/src/io/port/fd-port.rkt b/racket/src/io/port/fd-port.rkt
index 1aedfe8ba2..af635c0fec 100644
--- a/racket/src/io/port/fd-port.rkt
+++ b/racket/src/io/port/fd-port.rkt
@@ -271,8 +271,8 @@
   ;; in atomic mode
   [buffer-mode
    (case-lambda
-     [(self) buffer-mode]
-     [(self mode) (set! buffer-mode mode)])]
+     [() buffer-mode]
+     [(mode) (set! buffer-mode mode)])]
 
   #:property
   [prop:file-stream (lambda (p) (fd-output-port-fd p))]