DBusObjectTree: always access refcount atomically

Reviewed-by: Cosimo Alfarano <cosimo.alfarano@collabora.co.uk>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=38005

diff --git a/dbus/dbus-object-tree.c b/dbus/dbus-object-tree.c
index 28cfc8b..d244045 100644 (file)
--- a/dbus/dbus-object-tree.c
+++ b/dbus/dbus-object-tree.c
@@ -950,7 +950,7 @@ allocate_subtree_object (const char *name)
 
   len = strlen (name);
 
-  subtree = dbus_malloc (MAX (front_padding + (len + 1), sizeof (DBusObjectSubtree)));
+  subtree = dbus_malloc0 (MAX (front_padding + (len + 1), sizeof (DBusObjectSubtree)));
 
   if (subtree == NULL)
     return NULL;
@@ -987,7 +987,7 @@ _dbus_object_subtree_new (const char                  *name,
     }
 
   subtree->user_data = user_data;
-  subtree->refcount.value = 1;
+  _dbus_atomic_inc (&subtree->refcount);
   subtree->subtrees = NULL;
   subtree->n_subtrees = 0;
   subtree->max_subtrees = 0;
@@ -1002,8 +1002,14 @@ _dbus_object_subtree_new (const char                  *name,
 static DBusObjectSubtree *
 _dbus_object_subtree_ref (DBusObjectSubtree *subtree)
 {
-  _dbus_assert (subtree->refcount.value > 0);
+#ifdef DBUS_DISABLE_ASSERT
   _dbus_atomic_inc (&subtree->refcount);
+#else
+  dbus_int32_t old_value;
+
+  old_value = _dbus_atomic_inc (&subtree->refcount);
+  _dbus_assert (old_value > 0);
+#endif
 
   return subtree;
 }
@@ -1011,9 +1017,12 @@ _dbus_object_subtree_ref (DBusObjectSubtree *subtree)
 static void
 _dbus_object_subtree_unref (DBusObjectSubtree *subtree)
 {
-  _dbus_assert (subtree->refcount.value > 0);
+  dbus_int32_t old_value;
+
+  old_value = _dbus_atomic_dec (&subtree->refcount);
+  _dbus_assert (old_value > 0);
 
-  if (_dbus_atomic_dec (&subtree->refcount) == 1)
+  if (old_value == 1)
     {
       _dbus_assert (subtree->unregister_function == NULL);
       _dbus_assert (subtree->message_function == NULL);