Commit ee41106a authored Jul 28, 2023 by Steven Rostedt (Google)

tracing: Require all trace events to have a TRACE_SYSTEM

The creation of the trace event directory requires that a TRACE_SYSTEM is
defined that the trace event directory is added within the system it was
defined in.

The code handled the case where a TRACE_SYSTEM was not added, and would
then add the event at the events directory. But nothing should be doing
this. This code also prevents the implementation of creating dynamic
dentrys for the eventfs system.

As this path has never been hit on correct code, remove it. If it does get
hit, issues a WARN_ON_ONCE() and return ENODEV.

Link: https://lkml.kernel.org/r/1690568452-46553-2-git-send-email-akaher@vmware.com



Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

parent 6d98a0f2

kernel/trace/trace_events.c

+8 −7

Original line number	Diff line number	Diff line
		@@ -2420,14 +2420,15 @@ event_create_dir(struct dentry parent, struct trace_event_file file)

		/*
		* If the trace point header did not define TRACE_SYSTEM
		* then the system would be called "TRACE_SYSTEM".
		* then the system would be called "TRACE_SYSTEM". This should
		* never happen.
		*/
		if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
		if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0))
		return -ENODEV;

		d_events = event_subsystem_dir(tr, call->class->system, file, parent);
		if (!d_events)
		return -ENOMEM;
		} else
		d_events = parent;

		name = trace_event_name(call);
		file->dir = tracefs_create_dir(name, d_events);