From 952f25210408239bdf8840f6126d4c9e1129fbd9 Mon Sep 17 00:00:00 2001
From: Philippe Normand <philn@igalia.com>
Date: Fri, 5 Jan 2024 12:13:49 +0000
Subject: [PATCH] decodebin3: Fix clean-up of EOS'd parsebin src pad

In `parse_chain_output_probe()` the corresponding input stream might receive EOS
and thus be removed before the actual pad is removed. So we cannot assert about
this in `parsebin_pad_removed_cb()`.

Also, driving-by, protect `find_input_stream_for_pad()` with the selection lock
similarly to other functions accessing the input streams list.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5887>
---
 .../gst/playback/gstdecodebin3-parse.c               | 12 ++++++++++--
 .../gst-plugins-base/gst/playback/gstdecodebin3.c    | 10 ++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3-parse.c b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3-parse.c
index 2b7ce7ac13..b380d86fad 100644
--- a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3-parse.c
+++ b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3-parse.c
@@ -545,6 +545,7 @@ parsebin_pad_added_cb (GstElement * demux, GstPad * pad, DecodebinInput * input)
   SELECTION_UNLOCK (dbin);
 }
 
+/* WITH SELECTION_LOCK TAKEN! */
 static DecodebinInputStream *
 find_input_stream_for_pad (GstDecodebin3 * dbin, GstPad * pad)
 {
@@ -568,16 +569,23 @@ parsebin_pad_removed_cb (GstElement * demux, GstPad * pad, DecodebinInput * inp)
   if (!GST_PAD_IS_SRC (pad))
     return;
 
+  SELECTION_LOCK (dbin);
+
   GST_DEBUG_OBJECT (pad, "removed");
   input = find_input_stream_for_pad (dbin, pad);
-  g_assert (input);
+
+  if (input == NULL) {
+    GST_DEBUG_OBJECT (pad,
+        "Input stream not found, it was cleaned-up earlier after receiving EOS");
+    SELECTION_UNLOCK (dbin);
+    return;
+  }
 
   /* If there are no pending pads, this means we will definitely not need this
    * stream anymore */
 
   GST_DEBUG_OBJECT (pad, "Remove input stream %p", input);
 
-  SELECTION_LOCK (dbin);
   slot = get_slot_for_input (dbin, input);
   remove_input_stream (dbin, input);
 
diff --git a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
index 974180b8bd..09acb65c99 100644
--- a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
+++ b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
@@ -1233,9 +1233,15 @@ reset_input (GstDecodebin3 * dbin, DecodebinInput * input)
   }
   if (input->identity) {
     GstPad *idpad = gst_element_get_static_pad (input->identity, "src");
-    DecodebinInputStream *stream = find_input_stream_for_pad (dbin, idpad);
-    gst_object_unref (idpad);
+    DecodebinInputStream *stream;
+
+    SELECTION_LOCK (dbin);
+    stream = find_input_stream_for_pad (dbin, idpad);
     remove_input_stream (dbin, stream);
+    SELECTION_UNLOCK (dbin);
+
+    gst_object_unref (idpad);
+
     gst_element_set_state (input->identity, GST_STATE_NULL);
     gst_bin_remove (GST_BIN (dbin), input->identity);
     gst_clear_object (&input->identity);