Commit 130c0806 authored by Jiri Olsa's avatar Jiri Olsa Committed by Steven Rostedt (VMware)
Browse files

tracing: Add trampoline/graph selftest 

Adding selftest for checking that direct trampoline can
co-exist together with graph tracer on same function.

This is supported for CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
config option, which is defined only for x86_64 for now.

Link: https://lkml.kernel.org/r/20211008091336.33616-5-jolsa@kernel.org



Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 0c0593b4

kernel/trace/trace_selftest.c

+53 −1
Original line number Diff line number Diff line
@@ -784,6 +784,8 @@ static struct fgraph_ops fgraph_ops __initdata = { 
	.retfunc		= &trace_graph_return,

};



noinline __noclone static void trace_direct_tramp(void) { }



/*

 * Pretty much the same than for the function tracer from which the selftest

 * has been borrowed.
@@ -794,6 +796,7 @@ trace_selftest_startup_function_graph(struct tracer *trace, 
{

	int ret;

	unsigned long count;

	char *func_name __maybe_unused;



#ifdef CONFIG_DYNAMIC_FTRACE

	if (ftrace_filter_param) {
@@ -842,8 +845,57 @@ trace_selftest_startup_function_graph(struct tracer *trace, 
		goto out;

	}



	/* Don't test dynamic tracing, the function tracer already did */

#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS

	tracing_reset_online_cpus(&tr->array_buffer);

	set_graph_array(tr);



	/*

	 * Some archs *cough*PowerPC*cough* add characters to the

	 * start of the function names. We simply put a '*' to

	 * accommodate them.

	 */

	func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);

	ftrace_set_global_filter(func_name, strlen(func_name), 1);



	/*

	 * Register direct function together with graph tracer

	 * and make sure we get graph trace.

	 */

	ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,

				     (unsigned long) trace_direct_tramp);

	if (ret)

		goto out;



	ret = register_ftrace_graph(&fgraph_ops);

	if (ret) {

		warn_failed_init_tracer(trace, ret);

		goto out;

	}



	DYN_FTRACE_TEST_NAME();



	count = 0;



	tracing_stop();

	/* check the trace buffer */

	ret = trace_test_buffer(&tr->array_buffer, &count);



	unregister_ftrace_graph(&fgraph_ops);



	ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,

				       (unsigned long) trace_direct_tramp);

	if (ret)

		goto out;



	tracing_start();



	if (!ret && !count) {

		ret = -1;

		goto out;

	}

#endif



	/* Don't test dynamic tracing, the function tracer already did */

out:

	/* Stop it if we failed */

	if (ret)