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

From: Frederic Weisbecker
Date: Thu Jun 23 2011 - 19:14:02 EST

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

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
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");
printk("\nstack backtrace:\n");

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