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From: Tejun Heo <tj@kernel.org>
To: kernel test robot <xiaolong.ye@intel.com>
Cc: Jens Axboe <axboe@fb.com>,
	lkp@01.org, Jens Axboe <axboe@kernel.dk>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [writeback]  8bc4ad9498: INFO: suspicious RCU usage. ]
Date: Wed, 7 Sep 2016 12:41:03 -0400	[thread overview]
Message-ID: <20160907164103.GA1375@htj.duckdns.org> (raw)
In-Reply-To: <57c8012a.zlFYe5dba5wTaKD+%xiaolong.ye@intel.com>

On Thu, Sep 01, 2016 at 06:21:30PM +0800, kernel test robot wrote:
> 
> FYI, we noticed the following commit:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git wb-buf-throttle
> commit 8bc4ad9498f81d6689da42457615db0989e720d3 ("writeback: throttle buffered writeback")
> 
> in testcase: boot
> 
> on test machine: qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M
> 
> caused below changes:
> 
> 
> +--------------------------------------+------------+------------+
> |                                      | b2e4e4e34d | 8bc4ad9498 |
> +--------------------------------------+------------+------------+
> | boot_successes                       | 6          | 0          |
> | boot_failures                        | 0          | 8          |
> | INFO:suspicious_RCU_usage            | 0          | 8          |
> | message:INFO:suspicious_RCU_usage    | 0          | 0.0        |
> | pattern:INFO:suspicious_RCU_usage    | 0          | 0          |
> | calltrace:disk_events_workfn         | 0          | 8          |
> | message:calltrace:disk_events_workfn | 0          | 0.0        |
> | pattern:calltrace:disk_events_workfn | 0          | 0          |
> +--------------------------------------+------------+------------+
> 
> 
> 
> [    7.389264] stack backtrace:
> [    7.391300] CPU: 0 PID: 19 Comm: kworker/0:1 Not tainted 4.8.0-rc4-00008-g8bc4ad9 #1
> [    7.395279] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
> [    7.398012] Workqueue: events_freezable_power_ disk_events_workfn
> [    7.399933]  0000000000000000 ffff88003db1f8e8 ffffffff8178ed3b ffff88003db184c0
> [    7.404348]  0000000000000001 ffff88003db1f918 ffffffff81123472 ffff88003db184c0
> [    7.407158]  ffffffff84091180 0000000000000003 ffff880039d4c400 ffff88003db1f938
> [    7.410074] Call Trace:
> [    7.411328]  [<ffffffff8178ed3b>] dump_stack+0x82/0xb8
> [    7.413982]  [<ffffffff81123472>] lockdep_rcu_suspicious+0xf7/0x100
> [    7.415828]  [<ffffffff817873f4>] bio_blkcg+0x89/0x93
> [    7.417336]  [<ffffffff817891f0>] check_blkcg_changed+0x58/0x1b8

Hmm... can't reproduce here on qemu with v4.8-rc5 and the same kernel
config.  Can you please check whether it reproduces on v4.8-rc5?  If
so, is there any way I can get the qemu image and command line used?

Thanks.

-- 
tejun

  parent reply	other threads:[~2016-09-07 16:41 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
2016-09-07 16:41 ` Tejun Heo [this message]
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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