[Spice-devel] [PATCH spice-gtk v2 19/19] session: disconnect in idle

[Christophe Fergeau]

On Fri, Nov 14, 2014 at 12:32:42AM +0100, Marc-André Lureau wrote:
> This is a workaround for existing clients such as virt-viewer that do
> not hold a reference to their sessions when calling
> spice_session_disconnect() and crash now that channels are removed from
> session during the call. They expect disconnection events to be deferred
> instead, let's defer actual disconnection to idle time for public
> disconnect API for compatibility reasons (it is still recommended to fix
> client code, for eventual future iterations)

I'm afraid these changes are causing more issues. For example,
virt-viewer --reconnect + virsh destroy expects the session to stay
alive long enough, I needed this in order to fix it

commit 78a45c4236fee24eeaf4638cc00ea5fda4e22318
Author: Christophe Fergeau <cfergeau at redhat.com>
Date:   Tue Nov 18 15:38:33 2014 +0100

    keep session alive

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);

Then, I've also hit some issues with spice_channel_recv_link_hdr() if the guest
is destroyed while the input channel waits to receive the link messages. When this
happens, SpiceChannel::session is set to NULL in
spice_session_channel_destroy(). spice_channel_recv_link_hdr() will jump to error: and attempt
g_object_set(c->session, "protocol", 1, NULL); causing a critical as c->session is now NULL.

I suspect these are not the only places which could be impacted by such issues :(

Christophe
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