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Commit 9ea21c1e authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
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tracing/events: perform function tracing in event selftests 



We can find some bugs in the trace events if we stress the writes as well.
The function tracer is a good way to stress the events.

[ Impact: extend scope of event tracer self-tests ]

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090416161746.604786131@goodmis.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 69abe6a5

kernel/trace/trace_events.c

+72 −6
Original line number Diff line number Diff line
@@ -1017,7 +1017,7 @@ static __init void event_test_stuff(void) 
 * For every trace event defined, we will test each trace point separately,

 * and then by groups, and finally all trace points.

 */

static __init int event_trace_self_tests(void)

static __init void event_trace_self_tests(void)

{

	struct ftrace_event_call *call;

	struct event_subsystem *system;
@@ -1071,7 +1071,7 @@ static __init int event_trace_self_tests(void) 
		sysname = kstrdup(system->name, GFP_KERNEL);

		if (WARN_ON(!sysname)) {

			pr_warning("Can't allocate memory, giving up!\n");

			return 0;

			return;

		}

		ret = ftrace_set_clr_event(sysname, 1);

		kfree(sysname);
@@ -1086,7 +1086,7 @@ static __init int event_trace_self_tests(void) 
		sysname = kstrdup(system->name, GFP_KERNEL);

		if (WARN_ON(!sysname)) {

			pr_warning("Can't allocate memory, giving up!\n");

			return 0;

			return;

		}

		ret = ftrace_set_clr_event(sysname, 0);

		kfree(sysname);
@@ -1106,14 +1106,14 @@ static __init int event_trace_self_tests(void) 
	sysname = kmalloc(4, GFP_KERNEL);

	if (WARN_ON(!sysname)) {

		pr_warning("Can't allocate memory, giving up!\n");

		return 0;

		return;

	}

	memcpy(sysname, "*:*", 4);

	ret = ftrace_set_clr_event(sysname, 1);

	if (WARN_ON_ONCE(ret)) {

		kfree(sysname);

		pr_warning("error enabling all events\n");

		return 0;

		return;

	}



	event_test_stuff();
@@ -1125,10 +1125,76 @@ static __init int event_trace_self_tests(void) 


	if (WARN_ON_ONCE(ret)) {

		pr_warning("error disabling all events\n");

		return 0;

		return;

	}



	pr_cont("OK\n");

}



#ifdef CONFIG_FUNCTION_TRACER



static DEFINE_PER_CPU(atomic_t, test_event_disable);



static void

function_test_events_call(unsigned long ip, unsigned long parent_ip)

{

	struct ring_buffer_event *event;

	struct ftrace_entry *entry;

	unsigned long flags;

	long disabled;

	int resched;

	int cpu;

	int pc;



	pc = preempt_count();

	resched = ftrace_preempt_disable();

	cpu = raw_smp_processor_id();

	disabled = atomic_inc_return(&per_cpu(test_event_disable, cpu));



	if (disabled != 1)

		goto out;



	local_save_flags(flags);



	event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),

						  flags, pc);

	if (!event)

		goto out;

	entry	= ring_buffer_event_data(event);

	entry->ip			= ip;

	entry->parent_ip		= parent_ip;



	trace_current_buffer_unlock_commit(event, flags, pc);



 out:

	atomic_dec(&per_cpu(test_event_disable, cpu));

	ftrace_preempt_enable(resched);

}



static struct ftrace_ops trace_ops __initdata  =

{

	.func = function_test_events_call,

};



static __init void event_trace_self_test_with_function(void)

{

	register_ftrace_function(&trace_ops);

	pr_info("Running tests again, along with the function tracer\n");

	event_trace_self_tests();

	unregister_ftrace_function(&trace_ops);

}

#else

static __init void event_trace_self_test_with_function(void)

{

}

#endif



static __init int event_trace_self_tests_init(void)

{



	event_trace_self_tests();



	event_trace_self_test_with_function();



	return 0;

}