On Wed, 2017-10-04 at 14:08 -0400, Steven Rostedt wrote:
> 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?
>
Yeah, I think that makes sense, will change..
Thanks,
Tom
> -- Steve
>
>
> > + ret = remove_synth_event(event);
> > + if (!ret)
> > + free_synth_event(event);
> > + }
> > + out:
> > + mutex_unlock(&synth_event_mutex);
> > +
> > + return ret;
> > +}
> > +
> > +
