composition: Do not try to paused the task that could have been stopped

There was a race where we ended up trying to update the pipeline and
stop our children task at the exact moment where we were actually
setting its state to PAUSED. Take the composition lock and make sure
that can't happen

diff --git a/gnl/gnlcomposition.c b/gnl/gnlcomposition.c
index 1bfe590..ae95323 100644 (file)
--- a/gnl/gnlcomposition.c
+++ b/gnl/gnlcomposition.c
@@ -2748,7 +2748,16 @@ update_pipeline (GnlComposition * comp, GstClockTime currenttime, gint32 seqnum,
         (GstPadProbeCallback) _is_update_done_cb, ucompo,
         _free_update_compo_data);
 
+    GST_OBJECT_LOCK (comp);
+    if (comp->task == NULL) {
+      GST_INFO_OBJECT (comp,
+          "No task set, it must have been stopped, returning");
+      GST_OBJECT_UNLOCK (comp);
+      return FALSE;
+    }
+
     gst_task_pause (comp->task);
+    GST_OBJECT_UNLOCK (comp);
   }
 
   /* Activate stack */