leaks: Fix SIGSEGV detecting object type.

G_IS_OBJECT & GST_IS_OBJECT work by following pointers which is unsafe
on certain architectures. GstMiniObject detection however does a lookup
to see if it's a valid type derived from G_TYPE_BOXED.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/791>

diff --git a/plugins/tracers/gstleaks.c b/plugins/tracers/gstleaks.c
index 30bdc2d..b32c7d5 100644 (file)
--- a/plugins/tracers/gstleaks.c
+++ b/plugins/tracers/gstleaks.c
@@ -315,6 +315,13 @@ typedef struct
   const gchar *type_name;
 } ObjectLog;
 
+static inline gboolean
+object_is_gst_mini_object (gpointer obj)
+{
+  return (G_TYPE_IS_DERIVED (GST_MINI_OBJECT_TYPE (obj)) &&
+      G_TYPE_FUNDAMENTAL (GST_MINI_OBJECT_TYPE (obj)) == G_TYPE_BOXED);
+}
+
 static ObjectLog *
 object_log_new (gpointer obj)
 {
@@ -322,10 +329,10 @@ object_log_new (gpointer obj)
 
   o->object = obj;
 
-  if (G_IS_OBJECT (obj))
-    o->type_name = G_OBJECT_TYPE_NAME (obj);
-  else
+  if (object_is_gst_mini_object (obj))
     o->type_name = g_type_name (GST_MINI_OBJECT_TYPE (obj));
+  else
+    o->type_name = G_OBJECT_TYPE_NAME (obj);
 
   return o;
 }
@@ -594,18 +601,18 @@ create_leaks_list (GstLeaksTracer * self)
     GType type;
     guint ref_count;
 
-    if (GST_IS_OBJECT (obj)) {
-      if (GST_OBJECT_FLAG_IS_SET (obj, GST_OBJECT_FLAG_MAY_BE_LEAKED))
-        continue;
-
-      type = G_OBJECT_TYPE (obj);
-      ref_count = ((GObject *) obj)->ref_count;
-    } else {
+    if (object_is_gst_mini_object (obj)) {
       if (GST_MINI_OBJECT_FLAG_IS_SET (obj, GST_MINI_OBJECT_FLAG_MAY_BE_LEAKED))
         continue;
 
       type = GST_MINI_OBJECT_TYPE (obj);
       ref_count = ((GstMiniObject *) obj)->refcount;
+    } else {
+      if (GST_OBJECT_FLAG_IS_SET (obj, GST_OBJECT_FLAG_MAY_BE_LEAKED))
+        continue;
+
+      type = G_OBJECT_TYPE (obj);
+      ref_count = ((GObject *) obj)->ref_count;
     }
 
     l = g_list_prepend (l, leak_new (obj, type, ref_count, infos));
@@ -639,11 +646,10 @@ process_leak (Leak * leak, GValue * ret_leaks)
     /* for leaked objects, we take ownership of the object instead of
      * reffing ("collecting") it to avoid deadlocks */
     g_value_init (&obj_value, leak->type);
-    if (GST_IS_OBJECT (leak->obj))
-      g_value_take_object (&obj_value, leak->obj);
-    else
-      /* mini objects */
+    if (object_is_gst_mini_object (leak->obj))
       g_value_take_boxed (&obj_value, leak->obj);
+    else
+      g_value_take_object (&obj_value, leak->obj);
     s = gst_structure_new_empty ("object-alive");
     gst_structure_take_value (s, "object", &obj_value);
     gst_structure_set (s, "ref-count", G_TYPE_UINT, leak->ref_count,
@@ -734,11 +740,11 @@ gst_leaks_tracer_finalize (GObject * object)
   /* Remove weak references */
   g_hash_table_iter_init (&iter, self->objects);
   while (g_hash_table_iter_next (&iter, &obj, NULL)) {
-    if (GST_IS_OBJECT (obj))
-      g_object_weak_unref (obj, object_weak_cb, self);
-    else
+    if (object_is_gst_mini_object (obj))
       gst_mini_object_weak_unref (GST_MINI_OBJECT_CAST (obj),
           mini_object_weak_cb, self);
+    else
+      g_object_weak_unref (obj, object_weak_cb, self);
   }
 
   g_clear_pointer (&self->objects, g_hash_table_unref);