diff --git a/src/internal/poll/fd_unix.go b/src/internal/poll/fd_unix.go
index d9538e364b..c51370a682 100644
--- a/src/internal/poll/fd_unix.go
+++ b/src/internal/poll/fd_unix.go
@@ -26,6 +26,9 @@ type FD struct {
 	// Writev cache.
 	iovecs *[]syscall.Iovec
 
+	// Semaphore signaled when file is closed.
+	csema uint32
+
 	// Whether this is a streaming descriptor, as opposed to a
 	// packet-based descriptor like a UDP socket. Immutable.
 	IsStream bool
@@ -62,6 +65,7 @@ func (fd *FD) destroy() error {
 	fd.pd.close()
 	err := CloseFunc(fd.Sysfd)
 	fd.Sysfd = -1
+	runtime_Semrelease(&fd.csema)
 	return err
 }
 
@@ -79,7 +83,11 @@ func (fd *FD) Close() error {
 	fd.pd.evict()
 	// The call to decref will call destroy if there are no other
 	// references.
-	return fd.decref()
+	err := fd.decref()
+	// Wait until the descriptor is closed. If this was the only
+	// reference, it is already closed.
+	runtime_Semacquire(&fd.csema)
+	return err
 }
 
 // Shutdown wraps the shutdown network call.
diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go
index b0991a29f2..5118e3f769 100644
--- a/src/internal/poll/fd_windows.go
+++ b/src/internal/poll/fd_windows.go
@@ -278,6 +278,9 @@ type FD struct {
 	readbyte       []byte   // buffer to hold decoding of readuint16 from utf16 to utf8
 	readbyteOffset int      // readbyte[readOffset:] is yet to be consumed with file.Read
 
+	// Semaphore signaled when file is closed.
+	csema uint32
+
 	skipSyncNotif bool
 
 	// Whether this is a streaming descriptor, as opposed to a
@@ -399,6 +402,7 @@ func (fd *FD) destroy() error {
 		err = CloseFunc(fd.Sysfd)
 	}
 	fd.Sysfd = syscall.InvalidHandle
+	runtime_Semrelease(&fd.csema)
 	return err
 }
 
@@ -410,7 +414,11 @@ func (fd *FD) Close() error {
 	}
 	// unblock pending reader and writer
 	fd.pd.evict()
-	return fd.decref()
+	err := fd.decref()
+	// Wait until the descriptor is closed. If this was the only
+	// reference, it is already closed.
+	runtime_Semacquire(&fd.csema)
+	return err
 }
 
 // Shutdown wraps the shutdown network call.
diff --git a/src/net/listen_test.go b/src/net/listen_test.go
index 21ad4462f6..63fb144fdc 100644
--- a/src/net/listen_test.go
+++ b/src/net/listen_test.go
@@ -13,6 +13,7 @@ import (
 	"runtime"
 	"syscall"
 	"testing"
+	"time"
 )
 
 func (ln *TCPListener) port() string {
@@ -696,3 +697,34 @@ func multicastRIBContains(ip IP) (bool, error) {
 	}
 	return false, nil
 }
+
+// Issue 21856.
+func TestClosingListener(t *testing.T) {
+	listener, err := Listen("tcp", ":0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	addr := listener.Addr()
+
+	go func() {
+		for {
+			c, err := listener.Accept()
+			if err != nil {
+				return
+			}
+			c.Close()
+		}
+	}()
+
+	// Let the goroutine start. We don't sleep long: if the
+	// goroutine doesn't start, the test will pass without really
+	// testing anything, which is OK.
+	time.Sleep(time.Millisecond)
+
+	listener.Close()
+
+	_, err = Listen("tcp", addr.String())
+	if err != nil {
+		t.Error(err)
+	}
+}