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From: Tejun Heo <tj@kernel.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@fb.com>,
	kernel test robot <xiaolong.ye@intel.com>,
	lkp@01.org, Jens Axboe <axboe@kernel.dk>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ]
Date: Fri, 2 Sep 2016 14:00:51 -0400	[thread overview]
Message-ID: <20160902180051.GB18760@htj.duckdns.org> (raw)
In-Reply-To: <20160902170056.GN16261@linux.vnet.ibm.com>

Hello, Paul.

On Fri, Sep 02, 2016 at 10:00:56AM -0700, Paul E. McKenney wrote:
> Note that lockdep believes that the rcu_read_lock() has also been
> dropped, otherwise it would have listed it.

There isn't any actual code between rcu_read_lock() and the following
rcu deref.  That's the first thing which happens.  It looked
mysterious to me so I was wondering whether you knew any brekages on
rcu lockdep side.  Unfortunately, that doesn't seem to be the case.

> At this point, I have to suggest "git bisect"...

I'll try to reproduce it and see wth is going on.

Thanks!

-- 
tejun

  reply	other threads:[~2016-09-02 18:00 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-01 10:21 [writeback] 8bc4ad9498: INFO: suspicious RCU usage. ] kernel test robot
2016-09-01 20:13 ` Jens Axboe
2016-09-02 14:56   ` Tejun Heo
2016-09-02 15:36     ` Paul E. McKenney
2016-09-02 15:49       ` Jens Axboe
2016-09-02 17:00         ` Paul E. McKenney
2016-09-02 18:00           ` Tejun Heo [this message]
2016-09-07 16:41 ` Tejun Heo
2016-09-07 19:25   ` Jens Axboe
2016-09-08  1:43     ` [LKP] " Fengguang Wu
2016-09-08  2:04       ` Ye Xiaolong
2016-09-08 15:52         ` Jens Axboe
2016-09-09  0:46           ` Ye Xiaolong

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