hlsdemux: Fix dereferencing of NULL pointer

On some live HLS streams, gst_hls_demux_switch_playlist causes
assertion failures because it tried to dereference a NULL fragment.
This is because g_queue_peek_tail sometimes was returning NULL and
this case was not being checked.

This patch does two things:
* move the g_queue_peek_tail inside the semaphore protection
* check if q_queue_peek_tail returns NULL

https://bugzilla.gnome.org/show_bug.cgi?id=708849

diff --git a/ext/hls/gsthlsdemux.c b/ext/hls/gsthlsdemux.c
index 235af1f..57f1043 100644 (file)
--- a/ext/hls/gsthlsdemux.c
+++ b/ext/hls/gsthlsdemux.c
@@ -1213,11 +1213,12 @@ gst_hls_demux_switch_playlist (GstHLSDemux * demux)
   GstClockTime diff;
   gsize size;
   gint bitrate;
-  GstFragment *fragment = g_queue_peek_tail (demux->queue);
+  GstFragment *fragment;
   GstBuffer *buffer;
 
   GST_M3U8_CLIENT_LOCK (demux->client);
-  if (!demux->client->main->lists) {
+  fragment = g_queue_peek_tail (demux->queue);
+  if (!demux->client->main->lists || !fragment) {
     GST_M3U8_CLIENT_UNLOCK (demux->client);
     return TRUE;
   }