rcutorture: Dump # online CPUs on insufficient cb-flood laundering

This commit adds the number of online CPUs to the state dump following
an unsuccesful callback-flood test.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

kernel/rcu/rcutorture.c

@@ -2833,12 +2833,12 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
 	if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
 	    !shutdown_time_arrived()) {
 		WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
-		pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
+		pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld #online %u\n",
 			 __func__,
 			 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
 			 n_launders + n_max_cbs - n_launders_cb_snap,
 			 n_launders, n_launders_sa,
-			 n_max_gps, n_max_cbs, cver, gps);
+			 n_max_gps, n_max_cbs, cver, gps, num_online_cpus());
 		atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
 		mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
 		rcu_torture_fwd_cb_hist(rfp);