Re: Need help in debugging glib crash

[Tristan Van Berkom <tristan upstairslabs com>]

On Mon, 2015-05-25 at 16:42 +0300, Alexander Pyhalov wrote:
> On 05/25/2015 15:33, Alexander Pyhalov wrote:
> > Hello.
>
> > Here the program crashed.
> > So, we see that emit_in_idle() was called after entering to
> > g_file_monitor_dispose() function, which if I understand this correctly
> > lead to crash. Perhaps, some additional handling is necessary in
> > g_file_monitor_dispose() so that we don't try to emit signal to
> > "disposing" object ?  Do you have some thoughts on how to debug further
> > and fix this issue?
>
>
> Now I'm looking on the following patch:

Hi Alexander,

Since the introduction of GIO and async routines; occurrences where
an object fails to cancel one of it's ongoing operations in dispose()
have not been entirely uncommon.

The best would be to start with filing a bug in bugzilla and attaching
a test case which reproduces the crash.

Also, it's possible that the crash you're seeing might be reproducible
already with this existing test case[0].

Cheers,
    -Tristan

[0]:https://git.gnome.org/browse/gtk
+/tree/testsuite/gtk/objects-finalize.c


> --- gfilemonitor.c      2015-05-25 16:15:05.066580976 +0300
> +++ glib-2.43.4/gio/gfilemonitor.c      2015-05-25 16:15:49.053863042 +0300
> @@ -442,7 +442,7 @@
>     change->event_type = event_type;
>
>     g_mutex_lock (&monitor->priv->mutex);
> -  if (!priv->pending_file_change_source)
> +  if (!priv->pending_file_change_source && !priv->cancelled)
>       {
>         source = g_idle_source_new ();
>         priv->pending_file_change_source = source;
>
> Does it make sense? The idea is to avoid calling emit_cb after 
> g_file_monitor_dispose has already been called. I'm not sure if it's 
> correct approach, as we can not be sure that g_file_monitor_dispose will 
> work atomically.