[virt-tools-list] [virt-viewer 2/2] session: Don't hold VirtViewerDisplay refs on channel destroy
Marc-André Lureau
mlureau at redhat.com
Tue Nov 19 21:19:25 UTC 2013
----- Original Message -----
> VirtViewerSessionSpice creates a reference-holding VirtViewerDisplay
> array and associates it with the display SpiceChannel with
> g_object_set_data(channel, "virt-viewer-displays").
>
> When virt_viewer_session_spice_channel_destroy() is called and the display
> channel is being destroyed, we should ensure these VirtViewerDisplay
> references are dropped or the displays could outlive the session.
Should't it unref when the channel is disposed?
> In my testing (start qemu with a f20 live cd, connect to it, when the
> kernel has started booting and qxl is initialized (4 displays listed in the
> display submenu), kill qemu), I was getting "invalid unclassed pointer in
> cast to 'VirtViewerSessionSpice'" warnings through
>
> #0 0x00000035bac504e9 in g_logv (log_domain=0x35bb039aa4 "GLib-GObject",
> log_level=G_LOG_LEVEL_WARNING, format=<optimized out>,
> args=args at entry=0x7fffffffc7c0) at gmessages.c:989
> #1 0x00000035bac5063f in g_log (
> log_domain=log_domain at entry=0x35bb039aa4 "GLib-GObject",
> log_level=log_level at entry=G_LOG_LEVEL_WARNING,
> format=format at entry=0x35bb041010 "invalid unclassed pointer in cast
> to '%s'")
> at gmessages.c:1025
> #2 0x00000035bb032e09 in g_type_check_instance_cast
> (type_instance=0x665580,
> iface_type=<optimized out>) at gtype.c:4025
> #3 0x0000000000426e9f in get_main (self=0x894190) at
> virt-viewer-display-spice.c:92
> #4 0x0000000000426ece in show_hint_changed (self=0x894190)
> at virt-viewer-display-spice.c:100
> #5 0x00000035bb010298 in g_closure_invoke (closure=0x9f47c0,
> return_value=return_value at entry=0x0, n_param_values=2,
> param_values=param_values at entry=0x7fffffffcad0,
> invocation_hint=invocation_hint at entry=0x7fffffffca70) at
> gclosure.c:777
> #6 0x00000035bb02235d in signal_emit_unlocked_R
> (node=node at entry=0x651f60,
> detail=detail at entry=1782, instance=instance at entry=0x894190,
> emission_return=emission_return at entry=0x0,
> instance_and_params=instance_and_params at entry=0x7fffffffcad0) at
> gsignal.c:3586
> #7 0x00000035bb02a0f2 in g_signal_emit_valist (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>,
> var_args=var_args at entry=0x7fffffffcc60) at gsignal.c:3330
> #8 0x00000035bb02a3af in g_signal_emit (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3386
> #9 0x00000035bb014945 in g_object_dispatch_properties_changed
> (object=0x894190,
> n_pspecs=92, pspecs=0x0) at gobject.c:1047
> #10 0x00000035bb017019 in g_object_notify_by_spec_internal
> (pspec=<optimized out>,
> object=0x894190) at gobject.c:1141
> #11 g_object_notify (object=0x894190, property_name=<optimized out>) at
> gobject.c:1183
> #12 0x000000000041b617 in virt_viewer_display_set_show_hint
> (self=0x894190, mask=1,
> enable=0) at virt-viewer-display.c:659
> #13 0x000000000042712c in update_display_ready (self=0x894190)
> at virt-viewer-display-spice.c:156
> #14 0x00000035bb010298 in g_closure_invoke (closure=0x6ba480,
> return_value=return_value at entry=0x0, n_param_values=2,
> param_values=param_values at entry=0x7fffffffcfb0,
> invocation_hint=invocation_hint at entry=0x7fffffffcf50) at
> gclosure.c:777
> #15 0x00000035bb02235d in signal_emit_unlocked_R
> (node=node at entry=0x651f60,
> detail=detail at entry=1798, instance=instance at entry=0xa2c250,
> emission_return=emission_return at entry=0x0,
> instance_and_params=instance_and_params at entry=0x7fffffffcfb0) at
> gsignal.c:3586
> #16 0x00000035bb02a0f2 in g_signal_emit_valist (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>,
> var_args=var_args at entry=0x7fffffffd140) at gsignal.c:3330
> #17 0x00000035bb02a3af in g_signal_emit (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3386
> #18 0x00000035bb014945 in g_object_dispatch_properties_changed
> (object=0xa2c250,
> n_pspecs=92, pspecs=0x0) at gobject.c:1047
> #19 0x00000035bb017019 in g_object_notify_by_spec_internal
> (pspec=<optimized out>,
> object=0xa2c250) at gobject.c:1141
> #20 g_object_notify (object=0xa2c250, property_name=<optimized out>) at
> gobject.c:1183
> #21 0x00007ffff7044d9a in update_ready (display=0xa2c250) at
> spice-widget.c:257
> #22 0x00007ffff7044df0 in set_monitor_ready (self=0xa2c250, ready=0)
> at spice-widget.c:265
> #23 0x00007ffff7049bb3 in primary_destroy (channel=0x9f40b0,
> data=0xa2c250)
> at spice-widget.c:2131
> #24 0x00007ffff704afd5 in channel_destroy (s=0x892880, channel=0x9f40b0,
> data=0xa2c250)
> at spice-widget.c:2444
> #25 0x00000035bb010298 in g_closure_invoke (closure=0xa27850,
> return_value=return_value at entry=0x0, n_param_values=2,
> param_values=param_values at entry=0x7fffffffd570,
> invocation_hint=invocation_hint at entry=0x7fffffffd510) at
> gclosure.c:777
> #26 0x00000035bb02235d in signal_emit_unlocked_R
> (node=node at entry=0x7cf600,
> detail=detail at entry=0, instance=instance at entry=0x892880,
> emission_return=emission_return at entry=0x0,
> instance_and_params=instance_and_params at entry=0x7fffffffd570) at
> gsignal.c:3586
> #27 0x00000035bb02a0f2 in g_signal_emit_valist (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>,
> var_args=var_args at entry=0x7fffffffd700) at gsignal.c:3330
> #28 0x00000035bb02a3af in g_signal_emit (instance=<optimized out>,
> signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3386
> #29 0x00007ffff6ceba87 in spice_session_channel_destroy
> (session=0x892880,
> channel=0x9f40b0) at spice-session.c:1923
> #30 0x00007ffff6cecf05 in spice_channel_dispose (gobject=0x9f40b0)
> at spice-channel.c:149
> #31 0x00007ffff6cf912c in spice_display_channel_dispose (object=0x9f40b0)
> at channel-display.c:136
> #32 0x00000035bb014ee8 in g_object_unref (_object=0x9f40b0) at
> gobject.c:3160
> #33 0x00007ffff6cf300c in spice_channel_delayed_unref (data=0x9f40b0)
> at spice-channel.c:2135
> #34 0x00000035bac492a6 in g_main_dispatch (context=0x67a6b0) at
> gmain.c:3066
> #35 g_main_context_dispatch (context=context at entry=0x67a6b0) at
> gmain.c:3642
> #36 0x00000035bac49628 in g_main_context_iterate (context=0x67a6b0,
> block=block at entry=1, dispatch=dispatch at entry=1, self=<optimized out>)
> at gmain.c:3713
> #37 0x00000035bac49a3a in g_main_loop_run (loop=0x7baf60) at gmain.c:3907
> #38 0x00000035bfdaa2d5 in gtk_main () at gtkmain.c:1158
> #39 0x000000000042caf1 in main (argc=1, argv=0x7fffffffdc78) at
> remote-viewer-main.c:179
>
> In that backtrace, the last ref to the VirtViewerDisplay instances is held by
> the
> SpiceChannel:virt-viewer-displays object data which will only be released
> after
> completion of spice_display_channel_dispose()
> ---
> src/virt-viewer-session-spice.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/src/virt-viewer-session-spice.c
> b/src/virt-viewer-session-spice.c
> index 3c9e765..25a7f8c 100644
> --- a/src/virt-viewer-session-spice.c
> +++ b/src/virt-viewer-session-spice.c
> @@ -776,6 +776,7 @@ virt_viewer_session_spice_channel_destroy(G_GNUC_UNUSED
> SpiceSession *s,
>
> if (SPICE_IS_DISPLAY_CHANNEL(channel)) {
> DEBUG_LOG("zap display channel (#%d)", id);
> + g_object_set_data(G_OBJECT(channel), "virt-viewer-displays", NULL);
> }
ack anyway
> if (SPICE_IS_PLAYBACK_CHANNEL(channel) && self->priv->audio) {
> --
> 1.8.4.2
>
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