diff --git a/src/backends/native/meta-barrier-native.c b/src/backends/native/meta-barrier-native.c
index bdb006fb1..ebc1beaeb 100644
--- a/src/backends/native/meta-barrier-native.c
+++ b/src/backends/native/meta-barrier-native.c
@@ -43,6 +43,7 @@
 struct _MetaBarrierManagerNative
 {
   GHashTable *barriers;
+  GMutex mutex;
 };
 
 typedef enum
@@ -77,6 +78,7 @@ struct _MetaBarrierImplNative
   int                       trigger_serial;
   guint32                   last_event_time;
   MetaBarrierDirection      blocked_dir;
+  GMainContext             *context;
 };
 
 G_DEFINE_TYPE (MetaBarrierImplNative,
@@ -340,6 +342,48 @@ typedef struct _MetaBarrierEventData
   float               dy;
 } MetaBarrierEventData;
 
+typedef struct
+{
+  MetaBarrierEvent *event;
+  MetaBarrier *barrier;
+  MetaBarrierState state;
+} MetaBarrierIdleData;
+
+static gboolean
+emit_event_idle (MetaBarrierIdleData *idle_data)
+{
+  if (idle_data->state == META_BARRIER_STATE_HELD)
+    _meta_barrier_emit_hit_signal (idle_data->barrier, idle_data->event);
+  else
+    _meta_barrier_emit_left_signal (idle_data->barrier, idle_data->event);
+
+  meta_barrier_event_unref (idle_data->event);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+emit_event (MetaBarrierImplNative *self,
+            MetaBarrierEvent      *event)
+{
+  MetaBarrierIdleData *idle_data;
+  GSource *source;
+
+  idle_data = g_new0 (MetaBarrierIdleData, 1);
+  idle_data->state = self->state;
+  idle_data->barrier = self->barrier;
+  idle_data->event = event;
+
+  source = g_idle_source_new ();
+  g_source_set_priority (source, G_PRIORITY_HIGH);
+  g_source_set_callback (source,
+                         (GSourceFunc) emit_event_idle,
+                         idle_data,
+                         g_free);
+
+  g_source_attach (source, self->context);
+}
+
 static void
 emit_barrier_event (MetaBarrierImplNative *self,
                     guint32                time,
@@ -350,7 +394,6 @@ emit_barrier_event (MetaBarrierImplNative *self,
                     float                  dx,
                     float                  dy)
 {
-  MetaBarrier *barrier = self->barrier;
   MetaBarrierEvent *event = g_slice_new0 (MetaBarrierEvent);
   MetaBarrierState old_state = self->state;
 
@@ -389,12 +432,7 @@ emit_barrier_event (MetaBarrierImplNative *self,
 
   self->last_event_time = time;
 
-  if (self->state == META_BARRIER_STATE_HELD)
-    _meta_barrier_emit_hit_signal (barrier, event);
-  else
-    _meta_barrier_emit_left_signal (barrier, event);
-
-  meta_barrier_event_unref (event);
+  emit_event (self, event);
 }
 
 static void
@@ -479,6 +517,8 @@ meta_barrier_manager_native_process (MetaBarrierManagerNative *manager,
   if (!clutter_input_device_get_coords (device, NULL, &prev_pos))
     return;
 
+  g_mutex_lock (&manager->mutex);
+
   prev_x = prev_pos.x;
   prev_y = prev_pos.y;
 
@@ -523,6 +563,8 @@ meta_barrier_manager_native_process (MetaBarrierManagerNative *manager,
   g_hash_table_foreach (manager->barriers,
                         maybe_emit_barrier_event,
                         &barrier_event_data);
+
+  g_mutex_unlock (&manager->mutex);
 }
 
 static gboolean
@@ -549,7 +591,10 @@ _meta_barrier_impl_native_destroy (MetaBarrierImpl *impl)
 {
   MetaBarrierImplNative *self = META_BARRIER_IMPL_NATIVE (impl);
 
+  g_mutex_lock (&self->manager->mutex);
   g_hash_table_remove (self->manager->barriers, self);
+  g_mutex_unlock (&self->manager->mutex);
+  g_main_context_unref (self->context);
   self->is_active = FALSE;
 }
 
@@ -565,10 +610,13 @@ meta_barrier_impl_native_new (MetaBarrier *barrier)
 
   self->barrier = barrier;
   self->is_active = TRUE;
+  self->context = g_main_context_ref_thread_default ();
 
   manager = meta_seat_native_get_barrier_manager (META_SEAT_NATIVE (seat));
   self->manager = manager;
+  g_mutex_lock (&manager->mutex);
   g_hash_table_add (manager->barriers, self);
+  g_mutex_unlock (&manager->mutex);
 
   return META_BARRIER_IMPL (self);
 }
@@ -596,6 +644,7 @@ meta_barrier_manager_native_new (void)
   manager = g_new0 (MetaBarrierManagerNative, 1);
 
   manager->barriers = g_hash_table_new (NULL, NULL);
+  g_mutex_init (&manager->mutex);
 
   return manager;
 }