[PATCH v2 14/20] node_device_udev: nodeStateShutdownPrepare: Disconnect the signals explicitly

The documentation of gobject signals reads: "If you are connecting handlers to signals and using a GObject instance as your signal handler user data, you should remember to pair calls to g_signal_connect() with calls to g_signal_handler_disconnect() or g_signal_handlers_disconnect_by_func(). While signal handlers are automatically disconnected when the object emitting the signal is finalised..." [1] This means that the signal handlers are automatically disconnected as soon as the `priv->mdevCtlMonitors` are finalised/released by `udevEventDataDispose`. But this also means that it's possible that new work is tried to be scheduled for the workerpool by the `mdevctlEventHandleCallback` (main thread context) even if the workerpool has already been stopped by `nodeStateShutdownWait`. To fully understand this, it's important to know that the main loop of the main thread is still running for some time even after `nodeStateShutdownPrepare` has been called. Let's avoid this situation by explicitly disconnect the signals during `nodeStateShutdownPrepare`, which is called in the main thread, so that no new work is attempted to be scheduled for the worker pool. [1] https://docs.gtk.org/gobject/signals.html#memory-management-of-signal-han... Reviewed-by: Jonathon Jongsma <jjongsma(a)redhat.com&gt; Reviewed-by: Boris Fiuczynski <fiuczy(a)linux.ibm.com&gt; Signed-off-by: Marc Hartmayer <mhartmay(a)linux.ibm.com&gt; --- src/node_device/node_device_udev.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c index b2c5d11acbdf..2c9c7466da4a 100644 --- a/src/node_device/node_device_udev.c +++ b/src/node_device/node_device_udev.c @@ -2226,6 +2226,12 @@ nodeStateShutdownPrepare(void) if (!priv) return 0; + VIR_WITH_MUTEX_LOCK_GUARD(&priv->mdevctlLock) { + GList *tmp; + for (tmp = priv->mdevctlMonitors; tmp; tmp = tmp->next) + g_signal_handlers_disconnect_by_data(tmp->data, priv); + } + VIR_WITH_OBJECT_LOCK_GUARD(priv) { if (priv->mdevctlTimeout != -1) { virEventRemoveTimeout(priv->mdevctlTimeout); -- 2.34.1