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From: Larry Finger <Larry.Finger@lwfinger.net>
To: "Michael Büsch" <m@bues.ch>
Cc: "Rafał Miłecki" <zajec5@gmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	b43-dev <b43-dev@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Lockdep splat when unloading b43
Date: Sun, 24 Feb 2013 12:53:11 -0600	[thread overview]
Message-ID: <512A6197.2000908@lwfinger.net> (raw)
In-Reply-To: <20130224193239.3517e6ac@milhouse>

On 02/24/2013 12:32 PM, Michael B?sch wrote:
> On Sun, 24 Feb 2013 11:31:47 -0600
> Larry Finger <Larry.Finger@lwfinger.net> wrote:
>
>> With the current wireless-testing tree, unloading b43 produces the lockdep log
>> splat copied below. My understanding of locking is deficient, and I would like
>> to learn. Any help on understanding this problem is appreciated.
>
> A few questions:
> Is there any reason for using the global workqueue and not mac80211's workqueue?

My original thought was that we needed the firmware load queue before mac80211 
was running for b43; however, I now realize that my thinking was wrong.

> Why is the workqueue cancelled in the core_stop callback? Wouldn't it make more
> sense to cancel it in bcma_remove/ssb_remove?

It certainly would.

> This would probably fix the circular dependency. But I'm not entirely sure, because
> I'm not that familiar with the code anymore.

I know that a lot has changed, but your instincts are still good.

Thanks,

Larry

WARNING: multiple messages have this Message-ID (diff)
From: Larry Finger <Larry.Finger@lwfinger.net>
To: "Michael Büsch" <m@bues.ch>
Cc: "Rafał Miłecki" <zajec5@gmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	b43-dev <b43-dev@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Lockdep splat when unloading b43
Date: Sun, 24 Feb 2013 12:53:11 -0600	[thread overview]
Message-ID: <512A6197.2000908@lwfinger.net> (raw)
In-Reply-To: <20130224193239.3517e6ac@milhouse>

On 02/24/2013 12:32 PM, Michael Büsch wrote:
> On Sun, 24 Feb 2013 11:31:47 -0600
> Larry Finger <Larry.Finger@lwfinger.net> wrote:
>
>> With the current wireless-testing tree, unloading b43 produces the lockdep log
>> splat copied below. My understanding of locking is deficient, and I would like
>> to learn. Any help on understanding this problem is appreciated.
>
> A few questions:
> Is there any reason for using the global workqueue and not mac80211's workqueue?

My original thought was that we needed the firmware load queue before mac80211 
was running for b43; however, I now realize that my thinking was wrong.

> Why is the workqueue cancelled in the core_stop callback? Wouldn't it make more
> sense to cancel it in bcma_remove/ssb_remove?

It certainly would.

> This would probably fix the circular dependency. But I'm not entirely sure, because
> I'm not that familiar with the code anymore.

I know that a lot has changed, but your instincts are still good.

Thanks,

Larry




  reply	other threads:[~2013-02-24 18:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-24 17:31 Lockdep splat when unloading b43 Larry Finger
2013-02-24 18:14 ` Johannes Berg
2013-02-24 18:14   ` Johannes Berg
2013-02-24 19:38   ` Larry Finger
2013-02-24 19:38     ` Larry Finger
2013-02-24 18:32 ` Michael Büsch
2013-02-24 18:32   ` Michael Büsch
2013-02-24 18:53   ` Larry Finger [this message]
2013-02-24 18:53     ` Larry Finger

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