[PATCH 2/3] rcu: Inform the user about dynticks idle mode on PROVE_RCU warning

[Frederic Weisbecker <fweisbec@gmail.com>]

Inform the user if we are in extended quiescent state when
an illegal use of rcu is detected.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 kernel/lockdep.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index df2ad37..e77de90 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -4008,6 +4008,10 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 	printk("%s:%d %s!\n", file, line, s);
 	printk("\nother info that might help us debug this:\n\n");
 	printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks);
+
+	if (rcu_check_extended_qs())
+		printk("rcu is in extended quiescent state!\n");
+
 	lockdep_print_held_locks(curr);
 	printk("\nstack backtrace:\n");
 	dump_stack();
-- 
1.7.5.4