From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752835AbZHXQED (ORCPT ); Mon, 24 Aug 2009 12:04:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752776AbZHXQEB (ORCPT ); Mon, 24 Aug 2009 12:04:01 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:47152 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752630AbZHXQEA (ORCPT ); Mon, 24 Aug 2009 12:04:00 -0400 Date: Mon, 24 Aug 2009 09:03:59 -0700 From: "Paul E. McKenney" To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josht@linux.vnet.ibm.com, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org Subject: Re: [PATCH -tip] v3 Consolidate sparse and lockdep declarations in include/linux/rcupdate.h Message-ID: <20090824160359.GG6677@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20090727181401.GA14120@linux.vnet.ibm.com> <4A924296.3070308@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A924296.3070308@cn.fujitsu.com> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 24, 2009 at 03:34:46PM +0800, Lai Jiangshan wrote: > Paul E. McKenney wrote: > > From: Paul E. McKenney > > > > Signed-off-by: Paul E. McKenney > > --- [ . . . ] > > * rcu_read_lock_sched - mark the beginning of a RCU-classic critical section > > @@ -160,10 +190,14 @@ extern int rcu_scheduler_active; > > static inline void rcu_read_lock_sched(void) > > { > > preempt_disable(); > > + __acquire(RCU_SCHED); > > + rcu_read_acquire(); > > } > > static inline void rcu_read_lock_sched_notrace(void) > > It need be marked "notrace" too. I guess I just need to grep for "_notrace(" in my code. ;-) > > { > > preempt_disable_notrace(); > > + __acquire(RCU_SCHED); > > + rcu_read_acquire(); > > } > > It may cause infinity recursion. > rcu_read_acquire() calls rcu_read_lock_sched_notrace() > before current->lockdep_recursion is set to 1 when tracing in on, > thus infinity recursion occurs. That might explain Ingo's test results. Thank you again, good catch!!! Thanx, Paul