@@ -114,7 +114,7 @@ type Backend interface {

 	// PullOnBuild tells Docker to pull image referenced by `name`.

 	PullOnBuild(ctx context.Context, name string, authConfigs map[string]types.AuthConfig, output io.Writer) (Image, error)

 	// ContainerAttachRaw attaches to container.

-	ContainerAttachRaw(cID string, stdin io.ReadCloser, stdout, stderr io.Writer, stream bool) error

+	ContainerAttachRaw(cID string, stdin io.ReadCloser, stdout, stderr io.Writer, stream bool, attached chan struct{}) error

 	// ContainerCreate creates a new Docker container and returns potential warnings

 	ContainerCreate(config types.ContainerCreateConfig) (container.ContainerCreateCreatedBody, error)

 	// ContainerRm removes a container specified by `id`.

@@ -573,11 +573,18 @@ func (b *Builder) create() (string, error) {

 var errCancelled = errors.New("build cancelled")

 func (b *Builder) run(cID string) (err error) {

+	attached := make(chan struct{})

 	errCh := make(chan error)

 	go func() {

-		errCh <- b.docker.ContainerAttachRaw(cID, nil, b.Stdout, b.Stderr, true)

+		errCh <- b.docker.ContainerAttachRaw(cID, nil, b.Stdout, b.Stderr, true, attached)

 	}()

+	select {

+	case err := <-errCh:

+		return err

+	case <-attached:

+	}

+

 	finished := make(chan struct{})

 	cancelErrCh := make(chan error, 1)

 	go func() {

@@ -33,7 +33,7 @@ func (m *MockBackend) PullOnBuild(ctx context.Context, name string, authConfigs

 	return nil, nil

 }

-func (m *MockBackend) ContainerAttachRaw(cID string, stdin io.ReadCloser, stdout, stderr io.Writer, stream bool) error {

+func (m *MockBackend) ContainerAttachRaw(cID string, stdin io.ReadCloser, stdout, stderr io.Writer, stream bool, attached chan struct{}) error {

 	return nil

 }

@@ -73,7 +73,7 @@ func (daemon *Daemon) ContainerAttach(prefixOrName string, c *backend.ContainerA

 }

 // ContainerAttachRaw attaches the provided streams to the container's stdio

-func (daemon *Daemon) ContainerAttachRaw(prefixOrName string, stdin io.ReadCloser, stdout, stderr io.Writer, doStream bool) error {

+func (daemon *Daemon) ContainerAttachRaw(prefixOrName string, stdin io.ReadCloser, stdout, stderr io.Writer, doStream bool, attached chan struct{}) error {

 	container, err := daemon.GetContainer(prefixOrName)

 	if err != nil {

 		return err

@@ -86,6 +86,7 @@ func (daemon *Daemon) ContainerAttachRaw(prefixOrName string, stdin io.ReadClose

 		CloseStdin: container.Config.StdinOnce,

 	}

 	container.StreamConfig.AttachStreams(&cfg)

+	close(attached)

 	if cfg.UseStdin {

 		cfg.Stdin = stdin

 	}