public inbox for netdev@vger.kernel.org 
 help / color / mirror / Atom feed
From: Alexander Holler <holler@ahsoftware•de>
To: Lennert Buytenhek <buytenh@wantstofly•org>
Cc: Lubomir Rintel <lkundrak@v3•sk>,
	netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
	Lubomir Rintel <lubo.rintel@gooddata•com>
Subject: Re: [PATCH] mv643xx_eth: Fix a possible deadlock upon ifdown
Date: Fri, 01 Mar 2013 18:30:13 +0100	[thread overview]
Message-ID: <5130E5A5.90303@ahsoftware.de> (raw)
In-Reply-To: <20130104202509.GX27530@wantstofly.org>

Am 04.01.2013 21:25, schrieb Lennert Buytenhek:
> On Fri, Jan 04, 2013 at 03:07:02PM +0100, Lubomir Rintel wrote:
>
>> From: Lubomir Rintel <lubo.rintel@gooddata•com>
>>
>> =================================
>> [ INFO: inconsistent lock state ]
>> 3.7.0-6.luboskovo.fc19.armv5tel.kirkwood #1 Tainted: G        W
>> ---------------------------------
>> inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
>> NetworkManager/337 [HC0[0]:SC0[0]:HE1:SE1] takes:
>>   (_xmit_ETHER#2){+.?...}, at: [<bf07adfc>] txq_reclaim+0x54/0x264 [mv643xx_eth]

I get the same annoying warning when the MTU gets changed (through dhcp).

>
> Maybe I'm not reading it right, but I doubt that this is an actual
> deadlock or that the patch is needed.
>
> txq_reclaim() indeed doesn't disable BHs, but that's because it's
> always called in BH context.  Almost always -- the only exception is
> txq_deinit(), called from ->ndo_stop(), but by that time we've
> already napi_disable()'d and netif_carrier_off()'d and free_irq()'d.

Agreed. I've just read me through that too and don't think a deadlock is 
possible.

>
> How to explain that to lockdep, though, I don't know.

The patch helps with that. ;)

Regards,

Alexander

  reply	other threads:[~2013-03-01 17:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-04 14:07 [PATCH] mv643xx_eth: Fix a possible deadlock upon ifdown Lubomir Rintel
2013-01-04 14:17 ` Lubomir Rintel
2013-01-04 23:20   ` David Miller
2013-01-04 20:25 ` Lennert Buytenhek
2013-03-01 17:30   ` Alexander Holler [this message]
2013-03-12  2:49     ` Lennert Buytenhek
2013-03-12  9:04       ` Alexander Holler
2013-03-12 11:36         ` Alexander Holler

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=5130E5A5.90303@ahsoftware.de \
    --to=holler@ahsoftware$(echo .)de \
    --cc=buytenh@wantstofly$(echo .)org \
    --cc=linux-kernel@vger$(echo .)kernel.org \
    --cc=lkundrak@v3$(echo .)sk \
    --cc=lubo.rintel@gooddata$(echo .)com \
    --cc=netdev@vger$(echo .)kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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