diff --git a/autotest/test_inf.tcc b/autotest/test_inf.tcc
index c5f7028..08c318c 100644
--- a/autotest/test_inf.tcc
+++ b/autotest/test_inf.tcc
@@ -50,6 +50,7 @@ static void inf_create_user()
 static void inf_destroy_user()
 {
 	if (!inf_user) return;
+	hub_free(inf_user->connection);
 	hub_free(inf_user);
 	inf_user = 0;
 }
diff --git a/src/core/usermanager.c b/src/core/usermanager.c
index 4daf4ab..a1ee636 100644
--- a/src/core/usermanager.c
+++ b/src/core/usermanager.c
@@ -93,9 +93,12 @@ int uman_init(struct hub_info* hub)
 		return -1;
 	}
 
-	users->timeout = hub_malloc_zero(sizeof(struct timeout_evt));
-	timeout_evt_initialize(users->timeout, timer_statistics, hub);
-	timeout_queue_insert(net_backend_get_timeout_queue(), users->timeout, TIMEOUT_STATS);
+	if (net_backend_get_timeout_queue())
+	{
+		users->timeout = hub_malloc_zero(sizeof(struct timeout_evt));
+		timeout_evt_initialize(users->timeout, timer_statistics, hub);
+		timeout_queue_insert(net_backend_get_timeout_queue(), users->timeout, TIMEOUT_STATS);
+	}
 
 	hub->users = users;
 	return 0;
@@ -107,8 +110,11 @@ int uman_shutdown(struct hub_info* hub)
 	if (!hub || !hub->users)
 		return -1;
 
-	timeout_queue_remove(net_backend_get_timeout_queue(), hub->users->timeout);
-	hub_free(hub->users->timeout);
+	if (net_backend_get_timeout_queue())
+	{
+		timeout_queue_remove(net_backend_get_timeout_queue(), hub->users->timeout);
+		hub_free(hub->users->timeout);
+	}
 
 	if (hub->users->list)
 	{
diff --git a/src/network/epoll.c b/src/network/epoll.c
index cfaf5e1..e5bc1f2 100644
--- a/src/network/epoll.c
+++ b/src/network/epoll.c
@@ -99,6 +99,7 @@ void net_backend_shutdown()
 	net_cleanup_shutdown(g_backend->cleaner);
 	hub_free(g_backend->conns);
 	hub_free(g_backend);
+	g_backend = 0;
 }
 
 /**
@@ -135,6 +136,9 @@ int net_backend_process()
 
 struct timeout_queue* net_backend_get_timeout_queue()
 {
+	if (!g_backend)
+		return 0;
+
 	return &g_backend->timeout_queue;
 }
 
diff --git a/src/network/kqueue.c b/src/network/kqueue.c
index 86042e7..460858f 100644
--- a/src/network/kqueue.c
+++ b/src/network/kqueue.c
@@ -86,6 +86,7 @@ void net_backend_shutdown()
 	hub_free(g_backend->conns);
 	hub_free(g_backend->changes);
 	hub_free(g_backend);
+	g_backend = 0;
 }
 
 /**
@@ -124,6 +125,9 @@ int net_backend_process()
 
 struct timeout_queue* net_backend_get_timeout_queue()
 {
+	if (!g_backend)
+		return 0;
+
 	return &g_backend->timeout_queue;
 }
 
diff --git a/src/network/select.c b/src/network/select.c
index 0e32653..001eafc 100644
--- a/src/network/select.c
+++ b/src/network/select.c
@@ -88,6 +88,7 @@ void net_backend_shutdown()
 	net_cleanup_shutdown(g_backend->cleaner);
 	hub_free(g_backend->conns);
 	hub_free(g_backend);
+	g_backend = 0;
 }
 
 /**
@@ -149,6 +150,9 @@ int net_backend_process()
 
 struct timeout_queue* net_backend_get_timeout_queue()
 {
+	if (!g_backend)
+		return 0;
+
 	return &g_backend->timeout_queue;
 }