From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752281Ab0DSHzg (ORCPT ); Mon, 19 Apr 2010 03:55:36 -0400 Received: from hera.kernel.org ([140.211.167.34]:53108 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018Ab0DSHzf (ORCPT ); Mon, 19 Apr 2010 03:55:35 -0400 Date: Mon, 19 Apr 2010 07:54:41 GMT From: "tip-bot for Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, davem@davemloft.net, paulmck@linux.vnet.ibm.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, davem@davemloft.net, paulmck@linux.vnet.ibm.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20100415195039.GA22623@linux.vnet.ibm.com> References: <20100415195039.GA22623@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] rcu: Make RCU lockdep check the lockdep_recursion variable Message-ID: Git-Commit-ID: bc293d62b26ec590afc90a9e0a31c45d355b7bd8 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Mon, 19 Apr 2010 07:54:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bc293d62b26ec590afc90a9e0a31c45d355b7bd8 Gitweb: http://git.kernel.org/tip/bc293d62b26ec590afc90a9e0a31c45d355b7bd8 Author: Paul E. McKenney AuthorDate: Thu, 15 Apr 2010 12:50:39 -0700 Committer: Ingo Molnar CommitDate: Mon, 19 Apr 2010 08:37:19 +0200 rcu: Make RCU lockdep check the lockdep_recursion variable The lockdep facility temporarily disables lockdep checking by incrementing the current->lockdep_recursion variable. Such disabling happens in NMIs and in other situations where lockdep might expect to recurse on itself. This patch therefore checks current->lockdep_recursion, disabling RCU lockdep splats when this variable is non-zero. In addition, this patch removes the "likely()", as suggested by Lai Jiangshan. Reported-by: Frederic Weisbecker Reported-by: David Miller Tested-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: eric.dumazet@gmail.com LKML-Reference: <20100415195039.GA22623@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 5 +---- kernel/rcupdate.c | 7 +++++++ 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 9f1ddfe..07db2fe 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -101,10 +101,7 @@ extern struct lockdep_map rcu_sched_lock_map; # define rcu_read_release_sched() \ lock_release(&rcu_sched_lock_map, 1, _THIS_IP_) -static inline int debug_lockdep_rcu_enabled(void) -{ - return likely(rcu_scheduler_active && debug_locks); -} +extern int debug_lockdep_rcu_enabled(void); /** * rcu_read_lock_held - might we be in RCU read-side critical section? diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 63fe254..03a7ea1 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -69,6 +69,13 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); #ifdef CONFIG_DEBUG_LOCK_ALLOC +int debug_lockdep_rcu_enabled(void) +{ + return rcu_scheduler_active && debug_locks && + current->lockdep_recursion == 0; +} +EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled); + /** * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section? *