[Spice-devel] [spice-gtk] Don't call channel_connect from channel_disconnect in SWITCHING state

[Christophe Fergeau]

commit 26b7767 changed channel_disconnect() to call channel_connect()
instead of spice_channel_connect() when the channel state is
SPICE_CHANNEL_STATE_SWITCHING. However spice_channel_connect()
returns early when c->state >= SPICE_CHANNEL_STATE_CONNECTING without
doing anything, so calling channel_connect() instead is a significant
change of behaviour (SPICE_CHANNEL_STATE_SWITCHING int value is 4 while
SPICE_CHANNEL_STATE_CONNECTING is 2).

This is actually causing issues when a migration is cancelled.
If channel_disconnect is called from coroutine context when state is
SPICE_CHANNEL_STATE_SWITCHING:
- channel_connect() is called and queues an idle which will call
  connect_delayed()
- then spice_session_set_migration_state() is called and will call
  g_coroutine_object_notify(), which will queue an idle to emit the
  notification, and yield to the main context
- connect_delayed() gets called in an idle, resets the current
  coroutine, and then yield back to the coroutine context
- g_coroutine_object_notify() resumes and is confused as the
  notification did not happen.

This can be triggered by adding a g_usleep(10000000); at the beginning
of spice_session_start_migrating(), and by migrating a VM after
connecting to it.
---
 gtk/spice-channel.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/gtk/spice-channel.c b/gtk/spice-channel.c
index eec63b1..99c6748 100644
--- a/gtk/spice-channel.c
+++ b/gtk/spice-channel.c
@@ -2654,7 +2654,6 @@ static void channel_disconnect(SpiceChannel *channel)
     g_return_if_fail(SPICE_IS_CHANNEL(channel));
 
     if (c->state == SPICE_CHANNEL_STATE_SWITCHING) {
-        channel_connect(channel, c->tls);
         spice_session_set_migration_state(spice_channel_get_session(channel),
                                           SPICE_SESSION_MIGRATION_NONE);
     }
-- 
2.1.0