See https://github.com/kylelemons/gousb/pull/7

Merge branch 'fix-context-close-race' of https://github.com/krasin/gousb

usb/usb.go

@@ -27,7 +27,7 @@ import (
 
 type Context struct {
 	ctx  *C.libusb_context
-	done chan struct{}
+	done chan bool
 }
 
 func (c *Context) Debug(level int) {
@@ -36,7 +36,7 @@ func (c *Context) Debug(level int) {
 
 func NewContext() *Context {
 	c := &Context{
-		done: make(chan struct{}),
+		done: make(chan bool),
 	}
 
 	if errno := C.libusb_init(&c.ctx); errno != 0 {
@@ -44,13 +44,14 @@ func NewContext() *Context {
 	}
 
 	go func() {
+		tv := C.struct_timeval{0, 100000}
 		for {
 			select {
 			case <-c.done:
 				return
 			default:
 			}
-			if errno := C.libusb_handle_events(c.ctx); errno < 0 {
+			if errno := C.libusb_handle_events_timeout_completed(c.ctx, &tv, nil); errno < 0 {
 				log.Printf("handle_events: error: %s", usbError(errno))
 				continue
 			}
@@ -103,6 +104,7 @@ func (c *Context) ListDevices(each func(desc *Descriptor) bool) ([]*Device, erro
 }
 
 func (c *Context) Close() error {
+	c.done <- true
 	close(c.done)
 	if c.ctx != nil {
 		C.libusb_exit(c.ctx)

usb/usb_test.go

@@ -15,6 +15,9 @@
 package usb_test
 
 import (
+	"bytes"
+	"log"
+	"os"
 	"testing"
 
 	. "github.com/kylelemons/gousb/usb"
@@ -77,3 +80,22 @@ func TestEnum(t *testing.T) {
 		}
 	}
 }
+
+func TestMultipleContexts(t *testing.T) {
+	var buf bytes.Buffer
+	log.SetOutput(&buf)
+	for i := 0; i < 10; i++ {
+		ctx := NewContext()
+		_, err := ctx.ListDevices(func(desc *Descriptor) bool {
+			return false
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		ctx.Close()
+	}
+	log.SetOutput(os.Stderr)
+	if buf.Len() > 0 {
+		t.Errorf("Non zero output to log, while testing:  %s", buf.String())
+	}
+}