On Fri, 22 Sep 2017 15:00:01 -0500 Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> 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; > +} > + > + -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html