[tip:core/rcu] rcutorture: Print GP age upon forward-progress failure

["tip-bot for Paul E. McKenney" <tipbot@xxxxxxxxx>]

Commit-ID:  8dd3b54689d9a2103c0817f2b7adc51760a45551
Gitweb:     https://git.kernel.org/tip/8dd3b54689d9a2103c0817f2b7adc51760a45551
Author:     Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
AuthorDate: Wed, 3 Oct 2018 11:02:05 -0700
Committer:  Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
CommitDate: Sat, 1 Dec 2018 12:45:38 -0800

rcutorture: Print GP age upon forward-progress failure

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
 kernel/rcu/tree.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 90a67c75a447..f91631541965 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2682,6 +2682,8 @@ void rcu_fwd_progress_check(unsigned long j)
 	struct rcu_data *rdp;
 
 	if (rcu_gp_in_progress()) {
+		pr_info("%s: GP age %lu jiffies\n",
+			__func__, jiffies - rcu_state.gp_start);
 		show_rcu_gp_kthreads();
 	} else {
 		preempt_disable();