rcu: Add grace-period information to RCU CPU stall warnings

This commit causes the last grace period started and completed to be
printed on RCU CPU stall warning messages in order to aid diagnosis.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e78538712df0..8f4de3a7c1f7 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -947,8 +947,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
         raw_spin_unlock_irqrestore(&rnp->lock, flags);
 
         print_cpu_stall_info_end();
-        printk(KERN_CONT "(detected by %d, t=%ld jiffies)\n",
-               smp_processor_id(), (long)(jiffies - rsp->gp_start));
+        pr_cont("(detected by %d, t=%ld jiffies, g=%lu, c=%lu)\n",
+               smp_processor_id(), (long)(jiffies - rsp->gp_start),
+               rsp->gpnum, rsp->completed);
         if (ndetected == 0)
                 printk(KERN_ERR "INFO: Stall ended before state dump start\n");
         else if (!trigger_all_cpu_backtrace())
@@ -975,7 +976,8 @@ static void print_cpu_stall(struct rcu_state *rsp)
         print_cpu_stall_info_begin();
         print_cpu_stall_info(rsp, smp_processor_id());
         print_cpu_stall_info_end();
-        printk(KERN_CONT " (t=%lu jiffies)\n", jiffies - rsp->gp_start);
+        pr_cont(" (t=%lu jiffies g=%lu c=%lu)\n",
+                jiffies - rsp->gp_start, rsp->gpnum, rsp->completed);
         if (!trigger_all_cpu_backtrace())
                 dump_stack();