tracing: Fix use-after-free in hist_register_trigger()

This fixes a use-after-free case flagged by KASAN; make sure the test
happens before the potential free in this case.

Link: http://lkml.kernel.org/r/48f[e-mail]

Signed-off-by: Tom Zanussi <[e-mail]>
Signed-off-by: Steven Rostedt <[e-mail]>

kernel/trace/trace_events_hist.c

···
 		goto out;
 	}
 
+	if (hist_data->attrs->pause)
+		data->paused = true;
+
 	if (named_data) {
 		destroy_hist_data(data->private_data);
 		data->private_data = named_data->private_data;
 		set_named_trigger_data(data, named_data);
 		data->ops = &event_hist_trigger_named_ops;
 	}
-
-	if (hist_data->attrs->pause)
-		data->paused = true;
 
 	if (data->ops->init) {
 		ret = data->ops->init(data->ops, data);