From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Tue, 3 Sep 2019 17:44:24 +0000 (-0400)
Subject: bin: Fix minor race when adding to a bin
X-Git-Tag: 1.16.2~22
X-Git-Url: http://review.tizen.org/git/?p=platform%2Fupstream%2Fgstreamer.git;a=commitdiff_plain;h=94ba1cea88788fd3ad72fadcc2ceb7884ed6df50;ds=sidebyside

bin: Fix minor race when adding to a bin

This patch simply add a null check around a case where a child may have
been unparented concurrently to the deep_add_remove operation. This was
found by accident in the form of an "IS_GST_OBJECT" assertion, but had
no other known side effect in that test.
---

diff --git a/gst/gstbin.c b/gst/gstbin.c
index e5d4ecd..8e43d3f 100644
--- a/gst/gstbin.c
+++ b/gst/gstbin.c
@@ -1122,11 +1122,15 @@ gst_bin_do_deep_add_remove (GstBin * bin, gint sig_id, const gchar * sig_name,
       while ((e = g_queue_pop_head (&elements))) {
         GstObject *parent = gst_object_get_parent (GST_OBJECT_CAST (e));
 
-        GST_LOG_OBJECT (bin, "calling %s for element %" GST_PTR_FORMAT
-            " in bin %" GST_PTR_FORMAT, sig_name, e, parent);
-        g_signal_emit (bin, sig_id, 0, parent, e);
-        gst_object_unref (parent);
-        g_object_unref (e);
+        /* an element could have removed some of its internal elements
+         * meanwhile, so protect against that */
+        if (parent) {
+          GST_LOG_OBJECT (bin, "calling %s for element %" GST_PTR_FORMAT
+              " in bin %" GST_PTR_FORMAT, sig_name, e, parent);
+          g_signal_emit (bin, sig_id, 0, parent, e);
+          gst_object_unref (parent);
+          g_object_unref (e);
+        }
       }
     }
     gst_iterator_free (it);