tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
Now that some trace events can be protected by srcu_read_lock(tracepoint_srcu),
we need to make sure all locations that depend on this are also protected.
There were many places that did a synchronize_sched() thinking that it was
enough to protect againts access to trace events. This use to be the case,
but now that we use SRCU for _rcuidle() trace events, they may not be
protected by synchronize_sched(), as they may be called in paths that RCU is
not watching for preempt disable.
Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 58d21fd..750044e 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -34,7 +34,9 @@ void trigger_data_free(struct event_trigger_data *data)
if (data->cmd_ops->set_filter)
data->cmd_ops->set_filter(NULL, data, NULL);
- synchronize_sched(); /* make sure current triggers exit before free */
+ /* make sure current triggers exit before free */
+ tracepoint_synchronize_unregister();
+
kfree(data);
}
@@ -752,7 +754,7 @@ int set_trigger_filter(char *filter_str,
if (tmp) {
/* Make sure the call is done with the filter */
- synchronize_sched();
+ tracepoint_synchronize_unregister();
free_event_filter(tmp);
}