rcu-tasks: Make show_rcu_tasks_generic_gp_kthread() check all CPUs

Currently, the show_rcu_tasks_generic_gp_kthread() function only looks
at CPU 0's callback lists.  Although this is not fatal, it can confuse
debugging efforts in cases where any of the Tasks RCU flavors are in
per-CPU queueing mode.  This commit therefore causes this function to
scan all CPUs' callback queues.

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

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 405614039515a250782e5f7f02999f1fa06a9344..3aad0dfbfaf49133d49d7c479e0d681c2e2c2655 100644 (file)
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -582,7 +582,17 @@ static void __init rcu_tasks_bootup_oddness(void)
 /* Dump out rcutorture-relevant state common to all RCU-tasks flavors. */
 static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
 {
-       struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, 0); // for_each...
+       int cpu;
+       bool havecbs = false;
+
+       for_each_possible_cpu(cpu) {
+               struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+               if (!data_race(rcu_segcblist_empty(&rtpcp->cblist))) {
+                       havecbs = true;
+                       break;
+               }
+       }
        pr_info("%s: %s(%d) since %lu g:%lu i:%lu/%lu %c%c %s\n",
                rtp->kname,
                tasks_gp_state_getname(rtp), data_race(rtp->gp_state),
@@ -590,7 +600,7 @@ static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
                data_race(rcu_seq_current(&rtp->tasks_gp_seq)),
                data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),
                ".k"[!!data_race(rtp->kthread_ptr)],
-               ".C"[!data_race(rcu_segcblist_empty(&rtpcp->cblist))],
+               ".C"[havecbs],
                s);
 }
 #endif // #ifndef CONFIG_TINY_RCU