tracing: Add rcu dereference annotation for filter->prog

ftrace_function_set_filter() referenences filter->prog without annotation and sparse complains about it. It needs a rcu_dereference_protected() wrapper. Reported-by: kbuild test robot <[email protected]> Fixes: 8076559 ("tracing: Rewrite filter logic to be simpler and faster") Signed-off-by: Steven Rostedt (VMware) <[email protected]>
ambv · Apr 6, 2018 · 1f3b0fa · 1f3b0fa
1 parent 5125eee
commit 1f3b0fa
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
@@ -1992,7 +1992,8 @@ static bool is_or(struct prog_entry *prog, int i)
 static int ftrace_function_set_filter(struct perf_event *event,
 				      struct event_filter *filter)
 {
-	struct prog_entry *prog = filter->prog;
+	struct prog_entry *prog = rcu_dereference_protected(filter->prog,
+						lockdep_is_held(&event_mutex));
 	struct function_filter_data data = {
 		.first_filter  = 1,
 		.first_notrace = 1,