From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Jens Axboe <axboe@kernel.dk>
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 13:23:44 -0700 [thread overview]
Message-ID: <20170511202344.GL3956@linux.vnet.ibm.com> (raw)
In-Reply-To: <0b857dd2-8579-5657-f9c7-3b98645d8f0c@kernel.dk>
On Thu, May 11, 2017 at 02:12:39PM -0600, Jens Axboe wrote:
> 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.
Thank you, Jens! I will test it this evening, Pacific Time.
Thanx, Paul
next prev parent reply other threads:[~2017-05-11 20:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-10 22:34 Lockdep splat involving all_q_mutex 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
2017-05-11 20:23 ` Paul E. McKenney [this message]
2017-05-12 5:02 ` Paul E. McKenney
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170511202344.GL3956@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=axboe@kernel.dk \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox