From: Jens Axboe <axboe@kernel.dk>
To: paulmck@linux.vnet.ibm.com
Cc: peterz@infradead.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, tglx@linutronix.de
Subject: Re: Lockdep splat involving all_q_mutex
Date: Thu, 11 May 2017 14:12:39 -0600 [thread overview]
Message-ID: <0b857dd2-8579-5657-f9c7-3b98645d8f0c@kernel.dk> (raw)
In-Reply-To: <20170511031354.GB3956@linux.vnet.ibm.com>
On 05/10/2017 09:13 PM, Paul E. McKenney wrote:
> On Wed, May 10, 2017 at 08:55:54PM -0600, Jens Axboe wrote:
>> On 05/10/2017 04:34 PM, Paul E. McKenney wrote:
>>> Hello!
>>>
>>> I got the lockdep splat shown below during some rcutorture testing (which
>>> does CPU hotplug operations) on mainline at commit dc9edaab90de ("Merge
>>> tag 'acpi-extra-4.12-rc1' of git://git.kernel.org/.../rafael/linux-pm").
>>> My kneejerk reaction was just to reverse the "mutex_lock(&all_q_mutex);"
>>> and "get_online_cpus();" in blk_mq_init_allocated_queue(), but then
>>> I noticed that commit eabe06595d62 ("block/mq: Cure cpu hotplug lock
>>> inversion") just got done moving these two statements in the other
>>> direction.
>>
>> The problem is that that patch got merged too early, as it only
>> fixes a lockdep splat with the cpu hotplug rework. Fix is coming Linus'
>> way, it's in my for-linus tree.
>
> Thank you for the update, looking forward to the fix.
It's upstream now.
--
Jens Axboe
next prev parent reply other threads:[~2017-05-11 20:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-10 22:34 Paul E. McKenney
2017-05-11 2:55 ` Jens Axboe
2017-05-11 3:13 ` Paul E. McKenney
2017-05-11 20:12 ` Jens Axboe [this message]
2017-05-11 20:23 ` Paul E. McKenney
2017-05-12 5:02 ` Paul E. McKenney
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