data race?

type FireEffect struct {
        r       *rand.Rand
        lamp    lampbase.StripeLamp
        borders []borderpair
        stdDev  float64
        config  FireConfig
        ch      chan interface{}
        t       tomb.Tomb
        m       sync.RWMutex
}

func (f *FireEffect) Config() interface{} {
        f.m.RLock()
        conf := f.config
        f.m.RUnlock()
        return &conf
}

func (f *FireEffect) ConfigChan() chan interface{} {
        return f.ch
}

func (f *FireEffect) Tomb() *tomb.Tomb {
        return &f.t
}

func (f *FireEffect) Apply() {
        defer f.t.Done()
        for {
                select {
                case <-f.t.Dying():
                        close(f.ch)
                        return
                case confRecv := <-f.ch:
                        newConf, ok := confRecv.(*FireConfig)
                        if !ok {
                                close(f.ch)
                                f.t.Killf("Received config that wasn't *FireConfig", confRecv)
                                return
                        }
                        f.m.Lock()
                        f.config = *newConf
                        f.m.Unlock()
                default:
                }
                f.colorizeLamp()
                time.Sleep(30 * time.Millisecond)
        }

}