Re: [2.6.38-rc1] iwlagn lock misuse...

From: Daniel J Blueman
Date: Wed Jan 19 2011 - 05:11:19 EST


Hi Johannes,

On 19 January 2011 16:51, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote:
> On Wed, 2011-01-19 at 16:44 +0700, Daniel J Blueman wrote:
>> Booting an instrumented 2.6.38-rc1 kernel with an Intel WiFi Link 5300
>> card and associating with an access point, I see a lockdep warning
>> [attached].
>>
>> This is essentially (struct iwl_priv)->lock being taken with
>> interrupts disabled in iwl-agn-ict.c:152 [1] and the same lock taken
>> with interrupts enabled in rx.c:2476 [2] (confirmed via disassembly).
>>
>> It feels like this would have been introduced in this commit:
>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=6e8cc38d5b05bb812f89a35bd9bf52405e67d0df
>
> I think you're running into a lockdep false positive, it's not actually
> the same lock and lockdep confuses a few skb queue locks. Please apply
> this patch
> http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=commitdiff;h=53c16b8e752e8e58f4313f1155f3afadf78311bb
> and see if the problem persists.

Good move; it addresses the false-positive. I hope it can hit 2.6.38-rc2.

Thanks,
Daniel
--
Daniel J Blueman
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