tracing: Check pid filtering when creating events

commit 6cb206508b621a9a0a2c35b60540e399225c8243 upstream.

When pid filtering is activated in an instance, all of the events trace
files for that instance has the PID_FILTER flag set. This determines
whether or not pid filtering needs to be done on the event, otherwise the
event is executed as normal.

If pid filtering is enabled when an event is created (via a dynamic event
or modules), its flag is not updated to reflect the current state, and the
events are not filtered properly.

Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ea43be6b9cc3c776c0b3b52e824b484935a83aac..1ca64a9296d0de634b92ecd93bc5038813e9f880 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2255,12 +2255,19 @@ static struct trace_event_file *
 trace_create_new_event(struct trace_event_call *call,
                       struct trace_array *tr)
 {
+       struct trace_pid_list *pid_list;
        struct trace_event_file *file;
 
        file = kmem_cache_alloc(file_cachep, GFP_TRACE);
        if (!file)
                return NULL;
 
+       pid_list = rcu_dereference_protected(tr->filtered_pids,
+                                            lockdep_is_held(&event_mutex));
+
+       if (pid_list)
+               file->flags |= EVENT_FILE_FL_PID_FILTER;
+
        file->event_call = call;
        file->tr = tr;
        atomic_set(&file->sm_ref, 0);