fix goroutine leak in the DeleteCollection

staging/src/k8s.io/apiserver/pkg/registry/generic/registry/store.go

@@ -1126,14 +1126,22 @@ func (e *Store) DeleteCollection(ctx context.Context, deleteValidation rest.Vali
 	}
 	wg := sync.WaitGroup{}
 	toProcess := make(chan int, 2*workersNumber)
-	errs := make(chan error, workersNumber+1)
+	errs := make(chan error, workersNumber)
+	workersExited := make(chan struct{})
+	distributorExited := make(chan struct{})
 
 	go func() {
 		defer utilruntime.HandleCrash(func(panicReason interface{}) {
 			errs <- fmt.Errorf("DeleteCollection distributor panicked: %v", panicReason)
 		})
+		defer close(distributorExited)
 		for i := 0; i < len(items); i++ {
-			toProcess <- i
+			select {
+			case toProcess <- i:
+			case <-workersExited:
+				klog.V(4).InfoS("workers already exited, and there are some items waiting to be processed", "finished", i, "total", len(items))
+				return
+			}
 		}
 		close(toProcess)
 	}()
@@ -1166,6 +1174,9 @@ func (e *Store) DeleteCollection(ctx context.Context, deleteValidation rest.Vali
 		}()
 	}
 	wg.Wait()
+	// notify distributor to exit
+	close(workersExited)
+	<-distributorExited
 	select {
 	case err := <-errs:
 		return nil, err

staging/src/k8s.io/apiserver/pkg/registry/generic/registry/store_test.go

@@ -2124,6 +2124,37 @@ func TestStoreDeleteCollectionNotFound(t *testing.T) {
 	}
 }
 
+func TestStoreDeleteCollectionWorkDistributorExited(t *testing.T) {
+	destroyFunc, registry := NewTestGenericStoreRegistry(t)
+	defer destroyFunc()
+
+	testContext := genericapirequest.WithNamespace(genericapirequest.NewContext(), "test")
+
+	for i := 0; i < 100; i++ {
+		if _, err := registry.Create(
+			testContext,
+			&example.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: fmt.Sprintf("foo-%d", i),
+				},
+			},
+			rest.ValidateAllObjectFunc,
+			&metav1.CreateOptions{},
+		); err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+	}
+
+	expectErr := fmt.Errorf("validate object failed")
+
+	_, err := registry.DeleteCollection(testContext, func(ctx context.Context, obj runtime.Object) error {
+		return expectErr
+	}, nil, &metainternalversion.ListOptions{})
+	if err != expectErr {
+		t.Errorf("Unexpected error: %v", err)
+	}
+}
+
 // Test whether objects deleted with DeleteCollection are correctly delivered
 // to watchers.
 func TestStoreDeleteCollectionWithWatch(t *testing.T) {