On Fri, 22 Sep 2017 15:00:01 -0500
Tom Zanussi <tom.zanu...@linux.intel.com> wrote:
> +/* This function releases synth_event_mutex */
> +static int unregister_synth_event(struct synth_event *event)
> +{
> + struct trace_event_call *call = &event->call;
> + int ret;
> +
> + mutex_unlock(&synth_event_mutex);
> + ret = trace_remove_event_call(call);
> + mutex_lock(&synth_event_mutex);
> +
> + return ret;
> +}
> +
> +static int remove_synth_event(struct synth_event *event)
> +{
> + int ret = unregister_synth_event(event);
> +
> + if (!ret)
> + list_del(&event->list);
> +
> + return ret;
> +}
> +
> +/* This function releases synth_event_mutex */
> +static int release_all_synth_events(void)
> +{
> + struct synth_event *event, *e;
> + int ret = 0;
> +
> + mutex_lock(&synth_event_mutex);
> +
> + list_for_each_entry(event, &synth_event_list, list) {
> + if (event->ref) {
> + ret = -EBUSY;
> + goto out;
> + }
> + }
> +
> + list_for_each_entry_safe(event, e, &synth_event_list, list) {
remove_synth_event() releases synth_event_mutex, which is racy, as more
than one instance can do the deletion.
Perhaps we should remove all the events off the synth_event_list under
the lock, release the lock, and then remove the trace events attached
to them?
-- Steve
> + ret = remove_synth_event(event);
> + if (!ret)
> + free_synth_event(event);
> + }
> + out:
> + mutex_unlock(&synth_event_mutex);
> +
> + return ret;
> +}
> +
> +
