[virt-tools-list] [virt-viewer] VirtViewerDisplay: Keep a reference on VirtViewerDisplay::session

[Christophe Fergeau]

Hey,

For the record, I don't think this was ever committed, but I'm no longer
able to reproduce this issue with spice-gtk/virt-viewer from git master.

Christophe

On Tue, Nov 18, 2014 at 06:09:11PM +0100, Christophe Fergeau wrote:
> When using virt-viewer with --reconnect and a qemu+ssh libvirt
> connection, when killing the guest with 'virsh destroy', the
> VirtViewerSessionSpice instance would be destroyed when handling the
> SPICE_CHANNEL_ERROR_IO main channel event with
> virt_viewer_session_spice_main_channel_event, but the VirtViewerDisplay
> code would then try to use that just freed VirtViewerSessionSpice object
> as it has a reference to it:
> 
>     at virt-viewer-display-spice.c:79
>     at virt-viewer-display-spice.c:93
>     #5  0x0000003e1980fd35 in g_closure_invoke (closure=0xac6f00, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffc9d0, invocation_hint=invocation_hint at entry=0x7fffffffc970) at gclosure.c:768
>     #6  0x0000003e19821a42 in signal_emit_unlocked_R (node=node at entry=0x672eb0, detail=detail at entry=1769, instance=instance at entry=0x8a88b0, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffc9d0) at gsignal.c:3553
>     #7  0x0000003e1982a181 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffcb60) at gsignal.c:3309
>     at virt-viewer-display-spice.c:145
>     #14 0x0000003e1980fd35 in g_closure_invoke (closure=0xacaca0, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffcee0, invocation_hint=invocation_hint at entry=0x7fffffffce80) at gclosure.c:768
>     #15 0x0000003e19821a42 in signal_emit_unlocked_R (node=node at entry=0x672eb0, detail=detail at entry=1787, instance=instance at entry=0x89e5a0, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffcee0) at gsignal.c:3553
>     #16 0x0000003e1982a181 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffd070) at gsignal.c:3309
>     at gobject.c:1149
>     at spice-widget.c:244
>     at spice-widget.c:2132
> , signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3365
>     #25 0x0000003e1980fd35 in g_closure_invoke (closure=0xa96790, return_value=return_value at entry=0x0, n_param_values=2, param_values=param_values at entry=0x7fffffffd4d0, invocation_hint=invocation_hint at entry=0x7fffffffd470) at gclosure.c:768
>     #26 0x0000003e19821a42 in signal_emit_unlocked_R (node=node at entry=0x6ed870, detail=detail at entry=0, instance=instance at entry=0x8a8730, emission_return=emission_return at entry=0x0, instance_and_params=instance_and_params at entry=0x7fffffffd4d0) at gsignal.c:3553
>     #27 0x0000003e1982a181 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args at entry=0x7fffffffd660) at gsignal.c:3309
>     at spice-channel.c:156
>     at channel-display.c:134
> 
> The qemu+ssh case behaves differently from the local case as in the
> latter case, only a SPICE_CHANNEL_CLOSED event is received on the main
> channel when destroying the local guest.
> 
> This commit make VirtViewerDisplay take a reference on the
> VirtViewerSession object it uses so that it does not die early.
> ---
>  src/virt-viewer-display.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/src/virt-viewer-display.c b/src/virt-viewer-display.c
> index e6bc108..a42276e 100644
> --- a/src/virt-viewer-display.c
> +++ b/src/virt-viewer-display.c
> @@ -93,6 +93,16 @@ enum {
>  };
>  
>  static void
> +virt_viewer_display_finalize(GObject *obj)
> +{
> +    VirtViewerDisplay *display = VIRT_VIEWER_DISPLAY(obj);
> +    if (display->priv->session != NULL)
> +        g_clear_object(&display->priv->session);
> +
> +    G_OBJECT_CLASS(virt_viewer_display_parent_class)->finalize(obj);
> +}
> +
> +static void
>  virt_viewer_display_class_init(VirtViewerDisplayClass *class)
>  {
>      GObjectClass *object_class = G_OBJECT_CLASS(class);
> @@ -100,6 +110,7 @@ virt_viewer_display_class_init(VirtViewerDisplayClass *class)
>  
>      object_class->set_property = virt_viewer_display_set_property;
>      object_class->get_property = virt_viewer_display_get_property;
> +    object_class->finalize = virt_viewer_display_finalize;
>  
>  #if GTK_CHECK_VERSION(3, 0, 0)
>      widget_class->get_preferred_width = virt_viewer_display_get_preferred_width;
> @@ -316,7 +327,7 @@ virt_viewer_display_set_property(GObject *object,
>          break;
>      case PROP_SESSION:
>          g_warn_if_fail(priv->session == NULL);
> -        priv->session = g_value_get_object(value);
> +        priv->session = g_value_dup_object(value);
>          break;
>      case PROP_MONITOR:
>          priv->monitor = g_value_get_int(value);
> -- 
> 2.1.0
> 
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