diff --git a/examples/main.go b/examples/main.go
index 3d9e26d..413cb36 100644
--- a/examples/main.go
+++ b/examples/main.go
@@ -34,8 +34,8 @@ import (
 var sum int32
 
 func myFunc(i interface{}) error {
-	n := i.(int)
-	atomic.AddInt32(&sum, int32(n))
+	n := i.(int32)
+	atomic.AddInt32(&sum, n)
 	fmt.Printf("run with %d\n", n)
 	return nil
 }
@@ -73,7 +73,7 @@ func main() {
 	// submit tasks
 	for i := 0; i < runTimes; i++ {
 		wg.Add(1)
-		p.Serve(i)
+		p.Serve(int32(i))
 	}
 	wg.Wait()
 	fmt.Printf("running goroutines: %d\n", p.Running())
diff --git a/pool.go b/pool.go
index ee14834..72fc7e2 100644
--- a/pool.go
+++ b/pool.go
@@ -140,6 +140,7 @@ func (p *Pool) getWorker() *Worker {
 			p.running++
 		}
 	} else {
+		<-p.freeSignal
 		w = workers[n]
 		workers[n] = nil
 		p.workers = workers[:n]
@@ -148,20 +149,13 @@ func (p *Pool) getWorker() *Worker {
 
 	if waiting {
 		<-p.freeSignal
-		for {
-			p.lock.Lock()
-			workers = p.workers
-			l := len(workers) - 1
-			if l < 0 {
-				p.lock.Unlock()
-				continue
-			}
-			w = workers[l]
-			workers[l] = nil
-			p.workers = workers[:l]
-			p.lock.Unlock()
-			break
-		}
+		p.lock.Lock()
+		workers = p.workers
+		l := len(workers) - 1
+		w = workers[l]
+		workers[l] = nil
+		p.workers = workers[:l]
+		p.lock.Unlock()
 	} else if w == nil {
 		w = &Worker{
 			pool: p,