diff --git a/stack_gvisor.go b/stack_gvisor.go
index 795d963..792c461 100644
--- a/stack_gvisor.go
+++ b/stack_gvisor.go
@@ -152,6 +152,9 @@ func (t *GVisor) Start() error {
 }
 
 func (t *GVisor) Close() error {
+	if t.stack == nil {
+		return nil
+	}
 	t.endpoint.Attach(nil)
 	t.stack.Close()
 	for _, endpoint := range t.stack.CleanupEndpoints() {
diff --git a/stack_mixed.go b/stack_mixed.go
index c1abbb7..d2683cc 100644
--- a/stack_mixed.go
+++ b/stack_mixed.go
@@ -260,6 +260,9 @@ func (m *Mixed) packetLoop() {
 }
 
 func (m *Mixed) Close() error {
+	if m.stack == nil {
+		return nil
+	}
 	m.endpoint.Attach(nil)
 	m.stack.Close()
 	for _, endpoint := range m.stack.CleanupEndpoints() {