[PATCH 2/2] rcu-tasks: add RCU-tasks self tests

From: Uladzislau Rezki (Sony)
Date: Wed Dec 09 2020 - 15:29:21 EST


Add self tests for checking of RCU-tasks API functionality.
It covers:
- wait API functions;
- invoking/completion call_rcu_tasks*().

Self-tests are run when CONFIG_PROVE_RCU kernel parameter is set.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/tasks.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 67a162949763..9407772780c1 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1225,6 +1225,16 @@ void show_rcu_tasks_gp_kthreads(void)
}
#endif /* #ifndef CONFIG_TINY_RCU */

+static struct rcu_head rhp;
+static int rcu_execurted_test_counter;
+static int rcu_run_test_counter;
+
+static void test_rcu_tasks_callback(struct rcu_head *r)
+{
+ pr_info("RCU-tasks test callback executed %d\n",
+ ++rcu_execurted_test_counter);
+}
+
void __init rcu_init_tasks_generic(void)
{
#ifdef CONFIG_TASKS_RCU
@@ -1238,7 +1248,41 @@ void __init rcu_init_tasks_generic(void)
#ifdef CONFIG_TASKS_TRACE_RCU
rcu_spawn_tasks_trace_kthread();
#endif
+
+ if (IS_ENABLED(CONFIG_PROVE_RCU)) {
+ pr_info("Running RCU-tasks wait API self tests\n");
+#ifdef CONFIG_TASKS_RCU
+ rcu_run_test_counter++;
+ call_rcu_tasks(&rhp, test_rcu_tasks_callback);
+ synchronize_rcu_tasks();
+#endif
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+ rcu_run_test_counter++;
+ call_rcu_tasks_trace(&rhp, test_rcu_tasks_callback);
+ synchronize_rcu_tasks_rude();
+#endif
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+ rcu_run_test_counter++;
+ call_rcu_tasks_trace(&rhp, test_rcu_tasks_callback);
+ synchronize_rcu_tasks_trace();
+#endif
+ }
+}
+
+static int rcu_tasks_verify_self_tests(void)
+{
+ int ret = 0;
+
+ if (rcu_run_test_counter != rcu_execurted_test_counter) {
+ WARN_ON(1);
+ ret = -1;
+ }
+
+ return ret;
}
+late_initcall(rcu_tasks_verify_self_tests);

#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
static inline void rcu_tasks_bootup_oddness(void) {}
--
2.20.1