uridownloader: fix deadlock near EOS

A deadlock can happen when the source sends EOS when
being put to NULL as the object lock is being held by the
thread that sets the element to NULL and is needed by
the event handler.

1 files changed, 29 insertions, 37 deletions

diff --git a/gst-libs/gst/uridownloader/gsturidownloader.c b/gst-libs/gst/uridownloader/gsturidownloader.c
index 28e0aff79..d4c9fa775 100644
--- a/gst-libs/gst/uridownloader/gsturidownloader.c
+++ b/gst-libs/gst/uridownloader/gsturidownloader.c
@@ -249,41 +249,6 @@ done:
   }
 }
 
-/* Must be called with mutex locked. */
-static void
-gst_uri_downloader_stop (GstUriDownloader * downloader)
-{
-  GstPad *pad;
-  GstElement *urisrc;
-
-  if (!downloader->priv->urisrc)
-    return;
-
-  GST_DEBUG_OBJECT (downloader, "Stopping source element %s",
-      GST_ELEMENT_NAME (downloader->priv->urisrc));
-
-  /* remove the bus' sync handler */
-  gst_bus_set_sync_handler (downloader->priv->bus, NULL, NULL, NULL);
-  /* unlink the source element from the internal pad */
-  pad = gst_pad_get_peer (downloader->priv->pad);
-  if (pad) {
-    gst_pad_unlink (pad, downloader->priv->pad);
-    gst_object_unref (pad);
-  }
-  urisrc = downloader->priv->urisrc;
-  downloader->priv->urisrc = NULL;
-
-  GST_DEBUG_OBJECT (downloader, "Stopping source element %s",
-      GST_ELEMENT_NAME (urisrc));
-
-  /* set the element state to NULL */
-  gst_bus_set_flushing (downloader->priv->bus, TRUE);
-  gst_element_set_state (urisrc, GST_STATE_NULL);
-  gst_element_get_state (urisrc, NULL, NULL, GST_CLOCK_TIME_NONE);
-  gst_element_set_bus (urisrc, NULL);
-  gst_object_unref (urisrc);
-}
-
 void
 gst_uri_downloader_reset (GstUriDownloader * downloader)
 {
@@ -464,8 +429,35 @@ gst_uri_downloader_fetch_uri_with_range (GstUriDownloader * downloader,
 
 quit:
   {
-    gst_uri_downloader_stop (downloader);
-    GST_OBJECT_UNLOCK (downloader);
+    if (downloader->priv->urisrc) {
+      GstPad *pad;
+      GstElement *urisrc;
+
+      GST_DEBUG_OBJECT (downloader, "Stopping source element %s",
+          GST_ELEMENT_NAME (downloader->priv->urisrc));
+
+      /* remove the bus' sync handler */
+      gst_bus_set_sync_handler (downloader->priv->bus, NULL, NULL, NULL);
+      /* unlink the source element from the internal pad */
+      pad = gst_pad_get_peer (downloader->priv->pad);
+      if (pad) {
+        gst_pad_unlink (pad, downloader->priv->pad);
+        gst_object_unref (pad);
+      }
+      urisrc = downloader->priv->urisrc;
+      downloader->priv->urisrc = NULL;
+      GST_OBJECT_UNLOCK (downloader);
+
+      GST_DEBUG_OBJECT (downloader, "Stopping source element %s",
+          GST_ELEMENT_NAME (urisrc));
+
+      /* set the element state to NULL */
+      gst_bus_set_flushing (downloader->priv->bus, TRUE);
+      gst_element_set_state (urisrc, GST_STATE_NULL);
+      gst_element_get_state (urisrc, NULL, NULL, GST_CLOCK_TIME_NONE);
+      gst_element_set_bus (urisrc, NULL);
+      gst_object_unref (urisrc);
+    }
     g_mutex_unlock (&downloader->priv->download_lock);
     return download;
   }