team: fix teamd startup code (rh #1184923)danw/team-rh1184923

Since 03a5a85d, NMDeviceTeam was trying to use priv->teamd_pid to
decide whether a teamd_dbus_vanished() call indicated "teamd hasn't
been started yet" or "teamd was previously started and has now
exited". But this resulted in a race condition, where at startup, a
device could call g_dbus_watch_name(), then launch teamd (causing
teamd_pid to get set), and then have gdbus report that teamd hasn't
been started yet before the newly-launched teamd managed to grab the
bus name. Since teamd_pid would already be set when
teamd_dbus_vanished() was called, it would decide that this meant
"teamd was previously started and has now exited", so it would call
teamd_cleanup(), killing the just-started teamd process.

Fix this by having teamd_dbus_vanished() check priv->tdc instead,
which doesn't get set until after the first teamd_dbus_appeared()
call.

1 files changed, 4 insertions, 7 deletions

diff --git a/src/devices/team/nm-device-team.c b/src/devices/team/nm-device-team.c
index a03ad3f98b..88b1d0cb01 100644
--- a/src/devices/team/nm-device-team.c
+++ b/src/devices/team/nm-device-team.c
@@ -351,14 +351,11 @@ teamd_dbus_vanished (GDBusConnection *connection,
 
 	g_return_if_fail (priv->teamd_dbus_watch);
 
-	if (!priv->teamd_pid) {
+	if (!priv->tdc) {
 		/* g_bus_watch_name will always raise an initial signal, to indicate whether the
-		 * name exists/not exists initially. Do not take this as a failure, until the
-		 * startup timeout is over.
-		 *
-		 * Note that g_bus_watch_name is guaranteed to alternate vanished/appeared signals,
-		 * so we won't hit this condition again (because the next signal is either 'appeared'
-		 * or 'timeout'). */
+		 * name exists/not exists initially. Do not take this as a failure if it hadn't
+		 * previously appeared.
+		 */
 		_LOGD (LOGD_TEAM, "teamd not on D-Bus (ignored)");
 		return;
 	}