From: Jens Axboe <axboe@kernel.dk>
To: David Zarzycki <dave@znu.io>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: Hard LOCKUP on 4.15-rc9 + 'blkmq/for-next' branch
Date: Tue, 23 Jan 2018 11:00:06 -0700 [thread overview]
Message-ID: <07497a18-f638-d764-140a-c0de762571c2@kernel.dk> (raw)
In-Reply-To: <5103A5A8-E737-4ADC-939E-ACE84AD7DB70@znu.io>
On 1/23/18 10:54 AM, David Zarzycki wrote:
> Hi Jens,
>
> The bug still reproduces with this change. How confident are we that
> kernel objects are properly reference counted while they are
> throttled?
I would be surprised if it made a change, thanks for checking. Since
you're not pulling devices out of your system, is really nothing that
needs ref counting here. You don't have something running turning wbt
on/off during the run, I assume?
The whole thing is very odd. You do have lots of processes exiting with
segfaults and similar. The only thing I can think of is the wait queue
entry becoming invalid since it's on the stack, but I don't see how that
can happen. We should exit the wait path normally and remove ourselves
from the list.
--
Jens Axboe
next prev parent reply other threads:[~2018-01-23 18:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-22 23:31 Hard LOCKUP on 4.15-rc9 + 'blkmq/for-next' branch David Zarzycki
2018-01-22 23:34 ` Jens Axboe
2018-01-23 1:05 ` David Zarzycki
2018-01-23 1:20 ` Jens Axboe
2018-01-23 13:48 ` David Zarzycki
2018-01-23 15:34 ` Jens Axboe
2018-01-23 17:54 ` David Zarzycki
2018-01-23 18:00 ` Jens Axboe [this message]
2018-01-23 18:12 ` David Zarzycki
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