tracing: Add preempt disable for filter self test

The self testing for event filters does not really need preemption
disabled as there are no races at the time of testing, but the functions
it calls uses rcu_dereference_sched() which will complain if preemption
is not disabled.

Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 6a642e278241..816d3d074979 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -2101,6 +2101,11 @@ static __init int ftrace_test_event_filter(void)
                         break;
                 }
 
+                /*
+                 * The preemption disabling is not really needed for self
+                 * tests, but the rcu dereference will complain without it.
+                 */
+                preempt_disable();
                 if (*d->not_visited)
                         walk_pred_tree(filter->preds, filter->root,
                                        test_walk_pred_cb,
@@ -2108,6 +2113,7 @@ static __init int ftrace_test_event_filter(void)
 
                 test_pred_visited = 0;
                 err = filter_match_preds(filter, &d->rec);
+                preempt_enable();
 
                 __free_filter(filter);