tracing: Do not enable function event with enable

With the adding of function tracing event to perf, it caused a
side effect that produces the following warning when enabling all
events in ftrace:

 # echo 1 > /sys/kernel/debug/tracing/events/enable

[console]
event trace: Could not enable event function

This is because when enabling all events via the debugfs system
it ignores events that do not have a ->reg() function assigned.
This was to skip over the ftrace internal events (as they are
not TRACE_EVENTs). But as the ftrace function event now has
a ->reg() function attached to it for use with perf, it is no
longer ignored.

Worse yet, this ->reg() function is being called when it should
not be. It returns an error and causes the above warning to
be printed.

By adding a new event_call flag (TRACE_EVENT_FL_IGNORE_ENABLE)
and have all ftrace internel event structures have it set,
setting the events/enable will no longe try to incorrectly enable
the function event and does not warn.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 3dd15e8bc856..e039906b037d 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -180,6 +180,7 @@ struct ftrace_event_call __used event_##call = {			\
 	.event.type		= etype,				\
 	.class			= &event_class_ftrace_##call,		\
 	.print_fmt		= print,				\
+	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
 };									\
 struct ftrace_event_call __used						\
 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;