playbin3: Avoid group deactivation deadlock.

Change locking around group deactivation to avoid deadlocks
when shutting down exactly as a buffering message arrives.

The PLAYBIN3_LOCK now protects the active field of the
source group. Everything else is still protected by the
source-group-lock.

Also properly protect group switching operations with
the PLAYBIN3_LOCK everywhere.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1049>
This commit is contained in:
Jan Schmidt 2021-10-05 05:43:13 +11:00 committed by GStreamer Marge Bot
parent 1fa1b18a24
commit 33ad1cdc5e

View file

@ -2505,16 +2505,23 @@ gst_play_bin3_handle_message (GstBin * bin, GstMessage * msg)
GstSourceGroup *group;
/* Only post buffering messages for group which is currently playing */
GST_PLAY_BIN3_LOCK (playbin);
group = find_source_group_owner (playbin, msg->src);
GST_SOURCE_GROUP_LOCK (group);
if (!group->playing) {
GST_DEBUG_OBJECT (playbin, "Storing buffering message from pending group "
"%p %" GST_PTR_FORMAT, group, msg);
gst_message_replace (&group->pending_buffering_msg, msg);
gst_message_unref (msg);
msg = NULL;
if (group->active) {
GST_SOURCE_GROUP_LOCK (group);
GST_PLAY_BIN3_UNLOCK (playbin);
if (!group->playing) {
GST_DEBUG_OBJECT (playbin,
"Storing buffering message from pending group " "%p %"
GST_PTR_FORMAT, group, msg);
gst_message_replace (&group->pending_buffering_msg, msg);
gst_message_unref (msg);
msg = NULL;
}
GST_SOURCE_GROUP_UNLOCK (group);
} else {
GST_PLAY_BIN3_UNLOCK (playbin);
}
GST_SOURCE_GROUP_UNLOCK (group);
} else if (GST_MESSAGE_TYPE (msg) == GST_MESSAGE_STREAM_COLLECTION) {
GstStreamCollection *collection = NULL;
@ -4636,7 +4643,8 @@ error_cleanup:
}
}
/* must be called with PLAY_BIN_LOCK */
/* must be called with PLAY_BIN_LOCK, which is dropped temporarily
* if changing states */
static gboolean
deactivate_group (GstPlayBin3 * playbin, GstSourceGroup * group)
{
@ -4692,8 +4700,10 @@ deactivate_group (GstPlayBin3 * playbin, GstSourceGroup * group)
REMOVE_SIGNAL (group->uridecodebin, group->source_setup_id);
REMOVE_SIGNAL (group->uridecodebin, group->about_to_finish_id);
GST_PLAY_BIN3_UNLOCK (playbin);
gst_element_set_state (group->uridecodebin, GST_STATE_NULL);
gst_bin_remove (GST_BIN_CAST (playbin), group->uridecodebin);
GST_PLAY_BIN3_LOCK (playbin);
REMOVE_SIGNAL (group->uridecodebin, group->pad_added_id);
REMOVE_SIGNAL (group->uridecodebin, group->pad_removed_id);
@ -4766,6 +4776,7 @@ static gboolean
save_current_group (GstPlayBin3 * playbin)
{
GstSourceGroup *curr_group;
gboolean swapped = FALSE;
GST_DEBUG_OBJECT (playbin, "save current group");
@ -4773,12 +4784,16 @@ save_current_group (GstPlayBin3 * playbin)
GST_PLAY_BIN3_LOCK (playbin);
curr_group = playbin->curr_group;
if (curr_group && curr_group->valid && curr_group->active) {
/* unlink our pads with the sink */
deactivate_group (playbin, curr_group);
swapped = TRUE;
}
/* swap old and new */
playbin->curr_group = playbin->next_group;
playbin->next_group = curr_group;
if (swapped) {
/* unlink our pads with the sink */
deactivate_group (playbin, curr_group);
}
GST_PLAY_BIN3_UNLOCK (playbin);
return TRUE;
@ -4979,6 +4994,7 @@ gst_play_bin3_change_state (GstElement * element, GstStateChange transition)
if (do_save)
save_current_group (playbin);
/* Deactivate the groups, set uridecodebin to NULL and unref it */
GST_PLAY_BIN3_LOCK (playbin);
for (i = 0; i < 2; i++) {
if (playbin->groups[i].active && playbin->groups[i].valid) {
deactivate_group (playbin, &playbin->groups[i]);
@ -4993,6 +5009,7 @@ gst_play_bin3_change_state (GstElement * element, GstStateChange transition)
}
}
GST_PLAY_BIN3_UNLOCK (playbin);
/* Set our sinks back to NULL, they might not be child of playbin */
if (playbin->audio_sink)
@ -5034,6 +5051,8 @@ failure:
if (transition == GST_STATE_CHANGE_READY_TO_PAUSED) {
GstSourceGroup *curr_group;
GST_PLAY_BIN3_LOCK (playbin);
curr_group = playbin->curr_group;
if (curr_group) {
if (curr_group->active && curr_group->valid) {
@ -5046,6 +5065,8 @@ failure:
/* Swap current and next group back */
playbin->curr_group = playbin->next_group;
playbin->next_group = curr_group;
GST_PLAY_BIN3_UNLOCK (playbin);
}
return ret;
}