Commit a2d910f0 authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

tracing: Have function_graph selftest call cond_resched() 

When all kernel debugging is enabled (lockdep, KSAN, etc), the function
graph enabling and disabling can take several seconds to complete. The
function_graph selftest enables and disables function graph tracing
several times. With full debugging enabled, the soft lockup watchdog was
triggering because the selftest was running without ever scheduling.

Add cond_resched() throughout the test to make sure it does not trigger
the soft lockup detector.

Link: https://lkml.kernel.org/r/20230528051742.1325503-6-rostedt@goodmis.org



Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent ac9d2cb1

kernel/trace/trace_selftest.c

+10 −0
Original line number Diff line number Diff line
@@ -848,6 +848,12 @@ trace_selftest_startup_function_graph(struct tracer *trace, 
	}



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

	/*

	 * These tests can take some time to run. Make sure on non PREEMPT

	 * kernels, we do not trigger the softlockup detector.

	 */

	cond_resched();



	tracing_reset_online_cpus(&tr->array_buffer);

	set_graph_array(tr);
@@ -869,6 +875,8 @@ trace_selftest_startup_function_graph(struct tracer *trace, 
	if (ret)

		goto out;



	cond_resched();



	ret = register_ftrace_graph(&fgraph_ops);

	if (ret) {

		warn_failed_init_tracer(trace, ret);
@@ -891,6 +899,8 @@ trace_selftest_startup_function_graph(struct tracer *trace, 
	if (ret)

		goto out;



	cond_resched();



	tracing_start();



	if (!ret && !count) {