From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966400Ab0CPOsV (ORCPT ); Tue, 16 Mar 2010 10:48:21 -0400 Received: from hera.kernel.org ([140.211.167.34]:44597 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966383Ab0CPOsN (ORCPT ); Tue, 16 Mar 2010 10:48:13 -0400 Date: Tue, 16 Mar 2010 14:47:20 GMT From: tip-bot for Lai Jiangshan Cc: linux-kernel@vger.kernel.org, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, mingo@redhat.com, paulmck@linux.vnet.ibm.com, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com, mingo@elte.hu Reply-To: paulmck@linux.vnet.ibm.com, mingo@redhat.com, hpa@zytor.com, mathieu.desnoyers@polymtl.ca, linux-kernel@vger.kernel.org, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com, mingo@elte.hu In-Reply-To: <4B9F48AD.4000404@cn.fujitsu.com> References: <4B9F48AD.4000404@cn.fujitsu.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] rcu: Fix tracepoints & lockdep false positive Message-ID: Git-Commit-ID: 7f5b774275df8c76a959eae7488128b637fcbfc8 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]); Tue, 16 Mar 2010 14:47:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 7f5b774275df8c76a959eae7488128b637fcbfc8 Gitweb: http://git.kernel.org/tip/7f5b774275df8c76a959eae7488128b637fcbfc8 Author: Lai Jiangshan AuthorDate: Tue, 16 Mar 2010 17:00:29 +0800 Committer: Ingo Molnar CommitDate: Tue, 16 Mar 2010 10:10:40 +0100 rcu: Fix tracepoints & lockdep false positive tracepoint.h uses rcu_dereference(), which triggers this warning: [ 0.701161] =================================================== [ 0.702211] [ INFO: suspicious rcu_dereference_check() usage. ] [ 0.702716] --------------------------------------------------- [ 0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection! [ 0.703971] [ 0.703990] other info that might help us debug this: [ 0.703993] [ 0.705590] [ 0.705604] rcu_scheduler_active = 1, debug_locks = 0 [ 0.706712] 1 lock held by swapper/1: [ 0.707229] #0: (cpu_add_remove_lock){+.+.+.}, at: [] cpu_maps_update_begin+0x14/0x20 [ 0.710097] [ 0.710106] stack backtrace: [ 0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168 [ 0.713231] Call Trace: [ 0.713997] [] lockdep_rcu_dereference+0x9d/0xb0 [ 0.714746] [] create_workqueue_thread+0x107/0x110 [ 0.715353] [] ? worker_thread+0x0/0x340 [ 0.715845] [] __create_workqueue_key+0x138/0x240 [ 0.716427] [] ? cpu_maps_update_done+0x12/0x20 [ 0.717012] [] init_workqueues+0x6f/0x80 [ 0.717530] [] kernel_init+0x102/0x1f0 [ 0.717570] [] ? kernel_init+0x0/0x1f0 [ 0.718944] [] kernel_thread_helper+0x6/0x10 Signed-off-by: Lai Jiangshan Cc: Paul E. McKenney Cc: Mathieu Desnoyers Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4B9F48AD.4000404@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- include/linux/tracepoint.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index f59604e..78b4bd3 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -49,7 +49,7 @@ struct tracepoint { void **it_func; \ \ rcu_read_lock_sched_notrace(); \ - it_func = rcu_dereference((tp)->funcs); \ + it_func = rcu_dereference_sched((tp)->funcs); \ if (it_func) { \ do { \ ((void(*)(proto))(*it_func))(args); \