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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Eric Paris <eparis@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Miles Lane <miles.lane@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage
Date: Tue, 20 Apr 2010 06:28:39 -0700	[thread overview]
Message-ID: <20100420132839.GB2628@linux.vnet.ibm.com> (raw)
In-Reply-To: <1271766716.2972.16.camel@dhcp231-113.rdu.redhat.com>

On Tue, Apr 20, 2010 at 08:31:56AM -0400, Eric Paris wrote:
> On Tue, 2010-04-20 at 16:23 +0800, Lai Jiangshan wrote:
> 
> > [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage
> > 
> > When suspicious rcu_dereference_check() usage is detected, lockdep is still
> > available actually, so we should not call debug_locks_off() in
> > lockdep_rcu_dereference().
> > 
> > For get rid of too much "suspicious rcu_dereference_check() usage"
> > output when the "if(!debug_locks_off())" statement is removed. This patch uses
> > static variable '__warned's for very usage of "rcu_dereference*()".
> > 
> > One variable per usage, so, Now, we can get multiple complaint
> > when we detect multiple different suspicious rcu_dereference_check() usage.
> > 
> > Requested-by: Eric Paris <eparis@redhat.com>
> > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> 
> Although mine was a linux-next kernel and it doesn't appear that I have
> rcu_dereference_protected() at all, so I dropped that bit of the patch,
> it worked great!  I got 4 more complaints to harass people with.  Feel
> free to add my tested by if you care to.
> 
> Tested-by: Eric Paris <eparis@redhat.com>

Very nice!!!  Queued for urgent, thank you Lai and Eric!!!

							Thanx, Paul

  reply	other threads:[~2010-04-20 13:28 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-08  1:26 INFO: suspicious rcu_dereference_check() usage - include/linux/cgroup.h:492 invoked rcu_dereference_check() without protection! Miles Lane
2010-03-11  3:28 ` Paul E. McKenney
2010-04-12 18:44   ` Eric Paris
2010-04-12 18:47     ` Peter Zijlstra
2010-04-14 10:47       ` Peter Zijlstra
2010-04-15 15:47         ` Paul E. McKenney
2010-04-19  3:45           ` Lai Jiangshan
2010-04-19 18:26         ` Eric Paris
2010-04-19 23:01           ` Paul E. McKenney
2010-04-20  1:25             ` Eric Paris
2010-04-20  3:04               ` Paul E. McKenney
2010-04-20  7:21                 ` Peter Zijlstra
2010-04-20  8:23                 ` [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage Lai Jiangshan
2010-04-20  8:36                   ` Peter Zijlstra
2010-04-20 12:31                   ` Eric Paris
2010-04-20 13:28                     ` Paul E. McKenney [this message]
     [not found]                     ` <j2ya44ae5cd1004200545q6be4ec82o18ae99d93e8c29c7@mail.gmail.com>
2010-04-20 13:52                       ` Paul E. McKenney
2010-04-20 15:38                         ` Miles Lane
2010-04-21  6:04                           ` Borislav Petkov
2010-04-21 21:45                             ` Paul E. McKenney
2010-04-21 21:35                           ` Paul E. McKenney
2010-04-21 21:48                             ` Paul E. McKenney
2010-04-21 21:57                             ` Eric Dumazet
2010-04-21 22:14                               ` Paul E. McKenney
2010-04-21 23:26                                 ` Eric W. Biederman
2010-04-22 14:56                             ` Vivek Goyal
2010-04-22 16:01                               ` Paul E. McKenney
2010-04-23 12:50                                 ` Miles Lane
2010-04-23 19:42                                   ` Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 01/12] rcu: Fix RCU lockdep splat in set_task_cpu on fork path Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 02/12] rcu: fix RCU lockdep splat on freezer_fork path Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 03/12] rcu: leave lockdep enabled after RCU lockdep splat Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 04/12] NFSv4: Fix the locking in nfs_inode_reclaim_delegation() Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 05/12] NFS: Fix RCU issues in the NFSv4 delegation code Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 06/12] KEYS: Fix an RCU warning Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 07/12] KEYS: Fix an RCU warning in the reading of user keys Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 08/12] cgroup: Fix an RCU warning in cgroup_path() Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 09/12] cgroup: Fix an RCU warning in alloc_css_id() Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 10/12] sched: Fix an RCU warning in print_task() Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 11/12] cgroup: Check task_lock in task_subsys_state() Paul E. McKenney
2010-04-23 19:43                                     ` [PATCH v2.6.34-rc5 12/12] memcg: css_id() must be called under rcu_read_lock() Paul E. McKenney
2010-04-23 22:59                                     ` [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage Miles Lane
2010-04-24  5:35                                       ` Miles Lane
2010-04-25  2:36                                         ` Paul E. McKenney
2010-04-25  2:34                                       ` Paul E. McKenney
2010-04-25  7:45                                         ` Johannes Berg
2010-04-25  7:49                                           ` David Miller
2010-04-26  2:07                                             ` Paul E. McKenney
2010-04-25 15:49                                         ` Miles Lane
2010-04-25 20:20                                           ` Miles Lane
2010-04-26 16:09                                             ` Paul E. McKenney
2010-04-26 18:35                                               ` Eric W. Biederman
2010-04-27  4:27                                                 ` Paul E. McKenney
2010-04-27 16:22                                                   ` Paul E. McKenney
2010-04-27 16:33                                                     ` Eric Dumazet
2010-04-27 17:58                                                     ` Miles Lane
2010-04-27 23:31                                                       ` Paul E. McKenney
2010-04-27 23:42                                                         ` David Miller
2010-04-27 23:52                                                           ` Paul E. McKenney
     [not found]                                         ` <p2ka44ae5cd1004281358n86ce29d2tbece16b2fb974dab@mail.gmail.com>
2010-04-28 21:37                                           ` Paul E. McKenney
2010-05-01 17:26                         ` Miles Lane
2010-05-01 21:55                           ` Paul E. McKenney
2010-05-02  2:00                             ` Miles Lane
2010-05-02  4:11                               ` Paul E. McKenney
2010-04-21  1:05             ` INFO: suspicious rcu_dereference_check() usage - include/linux/cgroup.h:492 invoked rcu_dereference_check() without protection! Li Zefan
2010-04-21  3:14               ` Paul E. McKenney
2010-04-14 16:03     ` Paul E. McKenney
  -- strict thread matches above, loose matches on Subject: below --
2010-06-01 13:06 [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage Daniel J Blueman
2010-06-02 14:56 ` Paul E. McKenney
2010-06-02 15:24   ` Daniel J Blueman
2010-06-03  9:22   ` Li Zefan
2010-06-03 18:30     ` Paul E. McKenney
2010-06-04  2:44       ` Li Zefan
2010-06-04  4:10         ` Paul E. McKenney
2010-06-04  8:54           ` Daniel J Blueman

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