rcu: Additional information on RCU-tasks stall-warning messages
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index f86d1ae..9487b48 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -48,6 +48,7 @@
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/kthread.h>
+#include <linux/tick.h>
#define CREATE_TRACE_POINTS
@@ -461,6 +462,8 @@
static void check_holdout_task(struct task_struct *t,
bool needreport, bool *firstreport)
{
+ int cpu;
+
if (!ACCESS_ONCE(t->rcu_tasks_holdout) ||
t->rcu_tasks_nvcsw != ACCESS_ONCE(t->nvcsw) ||
!ACCESS_ONCE(t->on_rq) ||
@@ -477,6 +480,12 @@
pr_err("INFO: rcu_tasks detected stalls on tasks:\n");
*firstreport = false;
}
+ cpu = task_cpu(t);
+ pr_alert("%p: %c%c nvcsw: %lu/%lu holdout: %d idle_cpu: %d/%d\n",
+ t, ".I"[is_idle_task(t)],
+ "N."[cpu < 0 || !tick_nohz_full_cpu(cpu)],
+ t->rcu_tasks_nvcsw, t->nvcsw, t->rcu_tasks_holdout,
+ t->rcu_tasks_idle_cpu, cpu);
sched_show_task(t);
}