Re: [PATCH] tracing/filters: add filter_mutex to protect filter predicates

[Ingo Molnar <mingo@elte.hu>]

* Li Zefan <lizf@cn.fujitsu.com> wrote:

> Tom Zanussi wrote:
> > This patch adds a filter_mutex to prevent the filter predicates from
> > being accessed concurrently by various external functions.
> > 
> > It's based on a previous patch by Li Zefan:
> >         "[PATCH 7/7] tracing/filters: make filter preds RCU safe"
> > 
> > but any problems with it were added by me. ;-)
> > 
> > Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
> > 
> 
> Reviewed-and-tested-by: Li Zefan <lizf@cn.fujitsu.com>
> 
> except:
> 
> > @@ -348,17 +399,15 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
> >  		if (strcmp(call->system, system->name))
> >  			continue;
> >  
> > -		if (!find_event_field(call, pred->field_name))
> > -			continue;
> > -
> > -		err = filter_add_pred(call, pred);
> > +		err = __filter_add_pred(call, pred);
> >  		if (err == -ENOMEM) {
> >  			system->preds[system->n_preds] = NULL;
> > -			return err;
> > +			system->n_preds--;
> > +			break;
> 
> now we return 0 but not ENOMEM in this failure case.

ok - i'll wait for this fix.

	Ingo