rcutorture: Add torture tests for RCU Tasks Trace

This commit adds the definitions required to torture the tracing flavor
of RCU tasks.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/Kconfig.debug

@@ -30,6 +30,7 @@ config RCU_PERF_TEST
 	select SRCU
 	select TASKS_RCU
 	select TASKS_RUDE_RCU
+	select TASKS_TRACE_RCU
 	default n
 	help
 	  This option provides a kernel module that runs performance
@@ -48,6 +49,7 @@ config RCU_TORTURE_TEST
 	select SRCU
 	select TASKS_RCU
 	select TASKS_RUDE_RCU
+	select TASKS_TRACE_RCU
 	default n
 	help
 	  This option provides a kernel module that runs torture tests

kernel/rcu/rcu.h

@@ -442,6 +442,7 @@ enum rcutorture_type {
 	RCU_FLAVOR,
 	RCU_TASKS_FLAVOR,
 	RCU_TASKS_RUDE_FLAVOR,
+	RCU_TASKS_TRACING_FLAVOR,
 	RCU_TRIVIAL_FLAVOR,
 	SRCU_FLAVOR,
 	INVALID_RCU_FLAVOR

kernel/rcu/rcutorture.c

@@ -45,6 +45,7 @@
 #include <linux/sched/sysctl.h>
 #include <linux/oom.h>
 #include <linux/tick.h>
+#include <linux/rcupdate_trace.h>
 
 #include "rcu.h"
 
@@ -757,6 +758,45 @@ static struct rcu_torture_ops tasks_rude_ops = {
 	.name		= "tasks-rude"
 };
 
+/*
+ * Definitions for tracing RCU-tasks torture testing.
+ */
+
+static int tasks_tracing_torture_read_lock(void)
+{
+	rcu_read_lock_trace();
+	return 0;
+}
+
+static void tasks_tracing_torture_read_unlock(int idx)
+{
+	rcu_read_unlock_trace();
+}
+
+static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops tasks_tracing_ops = {
+	.ttype		= RCU_TASKS_TRACING_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= tasks_tracing_torture_read_lock,
+	.read_delay	= srcu_read_delay,  /* just reuse srcu's version. */
+	.readunlock	= tasks_tracing_torture_read_unlock,
+	.get_gp_seq	= rcu_no_completed,
+	.deferred_free	= rcu_tasks_tracing_torture_deferred_free,
+	.sync		= synchronize_rcu_tasks_trace,
+	.exp_sync	= synchronize_rcu_tasks_trace,
+	.call		= call_rcu_tasks_trace,
+	.cb_barrier	= rcu_barrier_tasks_trace,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.slow_gps	= 1,
+	.name		= "tasks-tracing"
+};
+
 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
 {
 	if (!cur_ops->gp_diff)
@@ -1323,6 +1363,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp)
 				  rcu_read_lock_bh_held() ||
 				  rcu_read_lock_sched_held() ||
 				  srcu_read_lock_held(srcu_ctlp) ||
+				  rcu_read_lock_trace_held() ||
 				  torturing_tasks());
 	if (p == NULL) {
 		/* Wait for rcu_torture_writer to get underway */
@@ -2440,7 +2481,8 @@ rcu_torture_init(void)
 	int firsterr = 0;
 	static struct rcu_torture_ops *torture_ops[] = {
 		&rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
-		&busted_srcud_ops, &tasks_ops, &tasks_rude_ops, &trivial_ops,
+		&busted_srcud_ops, &tasks_ops, &tasks_rude_ops,
+		&tasks_tracing_ops, &trivial_ops,
 	};
 
 	if (!torture_init_begin(torture_type, verbose))

tools/testing/selftests/rcutorture/configs/rcu/CFLIST

@@ -15,3 +15,4 @@ TASKS01
 TASKS02
 TASKS03
 RUDE01
+TRACE01

tools/testing/selftests/rcutorture/configs/rcu/TRACE01

@@ -0,0 +1,10 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=4
+CONFIG_HOTPLUG_CPU=y
+CONFIG_PREEMPT_NONE=y
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=n
+CONFIG_DEBUG_LOCK_ALLOC=y
+CONFIG_PROVE_LOCKING=y
+#CHECK#CONFIG_PROVE_RCU=y
+CONFIG_RCU_EXPERT=y

tools/testing/selftests/rcutorture/configs/rcu/TRACE01.boot

@@ -0,0 +1 @@
+rcutorture.torture_type=tasks-tracing