rcu: Make rcutorture emit online failures if verbose

Although rcutorture counts CPU-hotplug online failures, it does
not explicitly record which CPUs were having trouble coming online.
This commit therefore emits a console message when online failure occurs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 20ce3b6f9aa6..be63101c6175 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1434,7 +1434,13 @@ rcu_torture_onoff(void *arg)
                                          torture_type, cpu);
                         starttime = jiffies;
                         n_online_attempts++;
-                        if (cpu_up(cpu) == 0) {
+                        ret = cpu_up(cpu);
+                        if (ret) {
+                                if (verbose)
+                                        pr_alert("%s" TORTURE_FLAG
+                                                 "rcu_torture_onoff task: online %d failed: errno %d\n",
+                                                 torture_type, cpu, ret);
+                        } else {
                                 if (verbose)
                                         pr_alert("%s" TORTURE_FLAG
                                                  "rcu_torture_onoff task: onlined %d\n",