From: Jens Axboe <axboe@fb.com>
To: Tejun Heo <tj@kernel.org>, kernel test robot <xiaolong.ye@intel.com>
Cc: <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 13:25:54 -0600 [thread overview]
Message-ID: <6046dded-a2a6-b6e2-8c2c-0cf13accf1e9@fb.com> (raw)
In-Reply-To: <20160907164103.GA1375@htj.duckdns.org>
On 09/07/2016 10:41 AM, Tejun Heo wrote:
> 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?
I've been getting them for a while. I just updated the branch to -rc5
this morning, so if it does reproduce, the same mail would likely show
up again. I'll keep you posted :-)
The command line was in the original email:
$ qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M
And agree, in general it'd be nice if there was a link to the image as
well, so that folks can reproduce.
--
Jens Axboe
next prev parent reply other threads:[~2016-09-07 19:26 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
2016-09-07 19:25 ` Jens Axboe [this message]
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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