[PATCH 1/8] rcu: add a warn to rcu_preempt_note_context_switch()

From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>,
	Dipankar Sarma <dipankar@in.ibm.com>
Subject: [PATCH 1/8] rcu: add a warn to rcu_preempt_note_context_switch()
Date: Wed, 7 Aug 2013 18:24:57 +0800	[thread overview]
Message-ID: <1375871104-10688-2-git-send-email-laijs@cn.fujitsu.com> (raw)
In-Reply-To: <1375871104-10688-1-git-send-email-laijs@cn.fujitsu.com>

It is expected that _nesting == INT_MIN if _nesting < 0.
Add a warning to it if something unexpected happen.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 kernel/rcutree_plugin.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 63098a5..8fd947e 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -243,6 +243,7 @@ static void rcu_preempt_note_context_switch(int cpu)
 				       : rnp->gpnum + 1);
 		raw_spin_unlock_irqrestore(&rnp->lock, flags);
 	} else if (t->rcu_read_lock_nesting < 0 &&
+		   !WARN_ON_ONCE(t->rcu_read_lock_nesting != INT_MIN) &&
 		   t->rcu_read_unlock_special) {
 
 		/*
-- 
1.7.4.4

