[for-next][PATCH 17/18] tracing: Add rcu dereference annotation for filter->prog

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>

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 <fengguang.wu@xxxxxxxxx>
Fixes: 80765597bc587 ("tracing: Rewrite filter logic to be simpler and faster")
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace_events_filter.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 703a416aa5c2..cf8460caa95c 100644
--- 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,
-- 
2.15.1