All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michael Ellerman <mpe@ellerman.id.au>
To: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
	Sachin Sant <sachinp@linux.vnet.ibm.com>,
	linuxppc-dev@ozlabs.org
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: WARN @lib/refcount.c:128 during hot unplug of I/O adapter.
Date: Tue, 11 Apr 2017 19:00:08 +1000	[thread overview]
Message-ID: <871sszwc87.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <89aec36c-e352-e055-5e80-1235449762ce@linux.vnet.ibm.com>

Tyrel Datwyler <tyreld@linux.vnet.ibm.com> writes:

> On 04/06/2017 09:04 PM, Michael Ellerman wrote:
>> Tyrel Datwyler <tyreld@linux.vnet.ibm.com> writes:
>> 
>>> On 04/06/2017 03:27 AM, Sachin Sant wrote:
>>>> On a POWER8 LPAR running 4.11.0-rc5, a hot unplug operation on
>>>> any I/O adapter results in the following warning
>>>>
>>>> This problem has been in the code for some time now. I had first seen this in
>>>> -next tree.
>>>>
>
> <snip>
>
>>>> Have attached the dmesg log from the system. Let me know if any additional
>>>> information is required to help debug this problem.
>>>
>>> I remember you mentioning this when the issue was brought up for CPUs. I
>>> assume the case is the same here where the issue is only seen with
>>> adapters that were hot-added after boot (ie. hot-remove of adapter
>>> present at boot doesn't trip the warning)?
>> 
>> So who's fixing this?
>
> I started looking at it when Bharata submitted a patch trying to fix the
> issue for CPUs, but got side tracked by other things. I suspect that
> this underflow has actually been an issue for quite some time, and we
> are just now becoming aware of it thanks to the recount_t patchset being
> merged.

Yes I agree. Which means it might be broken in existing distros.

> I'll look into it again this week.

Thanks.

cheers

  reply	other threads:[~2017-04-11  9:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-06 10:27 WARN @lib/refcount.c:128 during hot unplug of I/O adapter Sachin Sant
2017-04-06 20:44 ` Tyrel Datwyler
2017-04-07  4:04   ` Michael Ellerman
2017-04-07  4:04     ` Michael Ellerman
2017-04-10 17:53     ` Tyrel Datwyler
2017-04-11  9:00       ` Michael Ellerman [this message]
2017-04-11 17:14         ` Tyrel Datwyler
2017-04-12  2:10           ` Michael Ellerman
2017-04-12 19:41             ` Tyrel Datwyler
2017-04-07  4:38   ` Sachin Sant
2017-04-07  4:38     ` Sachin Sant

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=871sszwc87.fsf@concordia.ellerman.id.au \
    --to=mpe@ellerman.id.au \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=nfont@linux.vnet.ibm.com \
    --cc=sachinp@linux.vnet.ibm.com \
    --cc=tyreld@linux.vnet.ibm.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.