Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEAD

doc.2015.07.15a: Documentation updates.
torture.2015.07.15a: Torture-test updates.

Documentation/RCU/rcu_dereference.txt

@@ -28,7 +28,7 @@ o	You must use one of the rcu_dereference() family of primitives
 o	Avoid cancellation when using the "+" and "-" infix arithmetic
 	operators.  For example, for a given variable "x", avoid
 	"(x-x)".  There are similar arithmetic pitfalls from other
-	arithmetic operatiors, such as "(x*0)", "(x/(x+1))" or "(x%1)".
+	arithmetic operators, such as "(x*0)", "(x/(x+1))" or "(x%1)".
 	The compiler is within its rights to substitute zero for all of
 	these expressions, so that subsequent accesses no longer depend
 	on the rcu_dereference(), again possibly resulting in bugs due

Documentation/kernel-parameters.txt

@@ -3135,22 +3135,35 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			in a given burst of a callback-flood test.
 
 	rcutorture.fqs_duration= [KNL]
-			Set duration of force_quiescent_state bursts.
+			Set duration of force_quiescent_state bursts
+			in microseconds.
 
 	rcutorture.fqs_holdoff= [KNL]
-			Set holdoff time within force_quiescent_state bursts.
+			Set holdoff time within force_quiescent_state bursts
+			in microseconds.
 
 	rcutorture.fqs_stutter= [KNL]
-			Set wait time between force_quiescent_state bursts.
+			Set wait time between force_quiescent_state bursts
+			in seconds.
+
+	rcutorture.gp_cond= [KNL]
+			Use conditional/asynchronous update-side
+			primitives, if available.
 
 	rcutorture.gp_exp= [KNL]
-			Use expedited update-side primitives.
+			Use expedited update-side primitives, if available.
 
 	rcutorture.gp_normal= [KNL]
-			Use normal (non-expedited) update-side primitives.
-			If both gp_exp and gp_normal are set, do both.
-			If neither gp_exp nor gp_normal are set, still
-			do both.
+			Use normal (non-expedited) asynchronous
+			update-side primitives, if available.
+
+	rcutorture.gp_sync= [KNL]
+			Use normal (non-expedited) synchronous
+			update-side primitives, if available.  If all
+			of rcutorture.gp_cond=, rcutorture.gp_exp=,
+			rcutorture.gp_normal=, and rcutorture.gp_sync=
+			are zero, rcutorture acts as if is interpreted
+			they are all non-zero.
 
 	rcutorture.n_barrier_cbs= [KNL]
 			Set callbacks/threads for rcu_barrier() testing.
@@ -3177,9 +3190,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Set time (s) between CPU-hotplug operations, or
 			zero to disable CPU-hotplug testing.
 
-	rcutorture.torture_runnable= [BOOT]
-			Start rcutorture running at boot time.
-
 	rcutorture.shuffle_interval= [KNL]
 			Set task-shuffle interval (s).  Shuffling tasks
 			allows some CPUs to go into dyntick-idle mode
@@ -3220,6 +3230,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Test RCU's dyntick-idle handling.  See also the
 			rcutorture.shuffle_interval parameter.
 
+	rcutorture.torture_runnable= [BOOT]
+			Start rcutorture running at boot time.
+
 	rcutorture.torture_type= [KNL]
 			Specify the RCU implementation to test.
 

kernel/rcu/rcutorture.c

@@ -686,10 +686,20 @@ static struct rcu_torture_ops tasks_ops = {
 
 #define RCUTORTURE_TASKS_OPS &tasks_ops,
 
+static bool __maybe_unused torturing_tasks(void)
+{
+	return cur_ops == &tasks_ops;
+}
+
 #else /* #ifdef CONFIG_TASKS_RCU */
 
 #define RCUTORTURE_TASKS_OPS
 
+static bool torturing_tasks(void)
+{
+	return false;
+}
+
 #endif /* #else #ifdef CONFIG_TASKS_RCU */
 
 /*
@@ -825,9 +835,7 @@ rcu_torture_cbflood(void *arg)
 	}
 	if (err) {
 		VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
-		while (!torture_must_stop())
-			schedule_timeout_interruptible(HZ);
-		return 0;
+		goto wait_for_stop;
 	}
 	VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
 	do {
@@ -846,6 +854,7 @@ rcu_torture_cbflood(void *arg)
 		stutter_wait("rcu_torture_cbflood");
 	} while (!torture_must_stop());
 	vfree(rhp);
+wait_for_stop:
 	torture_kthread_stopping("rcu_torture_cbflood");
 	return 0;
 }
@@ -1090,7 +1099,8 @@ static void rcu_torture_timer(unsigned long unused)
 	p = rcu_dereference_check(rcu_torture_current,
 				  rcu_read_lock_bh_held() ||
 				  rcu_read_lock_sched_held() ||
-				  srcu_read_lock_held(srcu_ctlp));
+				  srcu_read_lock_held(srcu_ctlp) ||
+				  torturing_tasks());
 	if (p == NULL) {
 		/* Leave because rcu_torture_writer is not yet underway */
 		cur_ops->readunlock(idx);
@@ -1164,7 +1174,8 @@ rcu_torture_reader(void *arg)
 		p = rcu_dereference_check(rcu_torture_current,
 					  rcu_read_lock_bh_held() ||
 					  rcu_read_lock_sched_held() ||
-					  srcu_read_lock_held(srcu_ctlp));
+					  srcu_read_lock_held(srcu_ctlp) ||
+					  torturing_tasks());
 		if (p == NULL) {
 			/* Wait for rcu_torture_writer to get underway */
 			cur_ops->readunlock(idx);
@@ -1509,7 +1520,7 @@ static int rcu_torture_barrier_init(void)
 	int i;
 	int ret;
 
-	if (n_barrier_cbs == 0)
+	if (n_barrier_cbs <= 0)
 		return 0;
 	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
 		pr_alert("%s" TORTURE_FLAG
@@ -1788,12 +1799,15 @@ rcu_torture_init(void)
 					  writer_task);
 	if (firsterr)
 		goto unwind;
-	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
-				   GFP_KERNEL);
-	if (fakewriter_tasks == NULL) {
-		VERBOSE_TOROUT_ERRSTRING("out of memory");
-		firsterr = -ENOMEM;
-		goto unwind;
+	if (nfakewriters > 0) {
+		fakewriter_tasks = kzalloc(nfakewriters *
+					   sizeof(fakewriter_tasks[0]),
+					   GFP_KERNEL);
+		if (fakewriter_tasks == NULL) {
+			VERBOSE_TOROUT_ERRSTRING("out of memory");
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
 	}
 	for (i = 0; i < nfakewriters; i++) {
 		firsterr = torture_create_kthread(rcu_torture_fakewriter,
@@ -1820,7 +1834,7 @@ rcu_torture_init(void)
 		if (firsterr)
 			goto unwind;
 	}
-	if (test_no_idle_hz) {
+	if (test_no_idle_hz && shuffle_interval > 0) {
 		firsterr = torture_shuffle_init(shuffle_interval * HZ);
 		if (firsterr)
 			goto unwind;

tools/testing/selftests/rcutorture/configs/rcu/TASKS01

@@ -5,6 +5,6 @@ CONFIG_PREEMPT_NONE=n
 CONFIG_PREEMPT_VOLUNTARY=n
 CONFIG_PREEMPT=y
 CONFIG_DEBUG_LOCK_ALLOC=y
-CONFIG_PROVE_LOCKING=n
-#CHECK#CONFIG_PROVE_RCU=n
+CONFIG_PROVE_LOCKING=y
+#CHECK#CONFIG_PROVE_RCU=y
 CONFIG_RCU_EXPERT=y