diff --git a/src/os/signal/signal_cgo_test.go b/src/os/signal/signal_cgo_test.go
index 16aeea8221..3c23090489 100644
--- a/src/os/signal/signal_cgo_test.go
+++ b/src/os/signal/signal_cgo_test.go
@@ -22,6 +22,7 @@ import (
 	"os/signal/internal/pty"
 	"strconv"
 	"strings"
+	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -113,7 +114,11 @@ func TestTerminalSignal(t *testing.T) {
 	const prompt = "prompt> "
 
 	// Read data from master in the background.
+	var wg sync.WaitGroup
+	wg.Add(1)
+	defer wg.Wait()
 	go func() {
+		defer wg.Done()
 		input := bufio.NewReader(master)
 		var line, handled []byte
 		for {