gmain: Close race condition in _g_main_wake_up_all_contexts()

Running gthread/tests/spawn-multithreaded in a loop, I very easily hit:

GLib-CRITICAL **: g_main_context_wakeup: assertion `g_atomic_int_get (&context->ref_count) > 0' failed

Testing the refcount still left a window where we would fall into the
assertion.  Fix this by just locking the context.

diff --git a/glib/gmain.c b/glib/gmain.c
index c84d7b9..47b26cc 100644 (file)
--- a/glib/gmain.c
+++ b/glib/gmain.c
@@ -3774,16 +3774,11 @@ _g_main_wake_up_all_contexts (void)
   G_LOCK (main_context_list);
   for (list = main_context_list; list; list = list->next)
     {
-      GMainContext *context;
-
-      context = list->data;
-      if (g_atomic_int_get (&context->ref_count) > 0)
-       /* Due to racing conditions we can find ref_count == 0, in
-        * that case, however, the context is still not destroyed
-        * and no poll can be active, otherwise the ref_count
-        * wouldn't be 0
-        */
-       g_main_context_wakeup (context);
+      GMainContext *context = list->data;
+
+      LOCK_CONTEXT (context);
+      g_main_context_wakeup_unlocked (context);
+      UNLOCK_CONTEXT (context);
     }
   G_UNLOCK (main_context_list);
 }
@@ -4635,8 +4630,6 @@ unix_signal_helper_thread (gpointer data)
        deliver_unix_signal (SIGINT);
       if (sighup_received)
        deliver_unix_signal (SIGHUP);
-      if (sigchld_received)
-       deliver_sigchld ();
       _g_main_wake_up_all_contexts ();
     }
 }