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From: "Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>
Date: Thu, 9 Aug 2012 15:14:23 -0700
Message-ID: <CAB=NE6UsqwuF2ZHSfSXaug=nRcKkzKbDuz7LU3v=TyOaf8vgZg@mail.gmail.com> (sfid-20120810_001449_908874_77FAFFCC)
Subject: Re: [PATCH v2] ath9k: decrypt_error flag issue
To: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Cc: linux-wireless@vger.kernel.org, Felix Fietkau <nbd@openwrt.org>,
	Pavel Roskin <proski@gnu.org>
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Sender: linux-wireless-owner@vger.kernel.org

On Thu, Aug 9, 2012 at 3:06 PM, Lorenzo Bianconi
<lorenzo.bianconi83@gmail.com> wrote:
>> On 2012-08-09 11:21 PM, Luis R. Rodriguez wrote:
>>> On Thu, Aug 9, 2012 at 2:07 PM, Pavel Roskin <proski@gnu.org> wrote:
>>>> On Thu, 9 Aug 2012 11:10:38 -0700
>>>> "Luis R. Rodriguez" <rodrigue@qca.qualcomm.com> wrote:
>>>>
>>>>> And this would lead to .. what? How did you realize this? Can you
>>>>> please resend and add all this information to the commit log message?
>>>>
>>>> Also please use a better subject.  For example:
>>>>
>>>> ath9k: fix decrypt_error initialization in ath_rx_tasklet()
>>>>
>>>> "issue" is too vague.
>>>
>>> Also -- what I was getting at is to evaluate whether or not this is an
>>> important fix or critical. To determine if its critical it helps to
>>> understand exactly what negative behavior was observed. If its
>>> critical it can go to stable but I have a feeling this is not
>>> critical. If its not critical and only important although it won't go
>>> to stable I'll still cherry pick it for the stable compat-wireless
>>> releases.
>> I think it's critical enough for stable. I think when using CCMP
>> encryption, high CPU load can get the connection stuck (because of CCMP
>> PN corruption when the issue occurs).
>>
>> - Felix
>>
>
>  I was using a two hop network encrypted with AES CCMP.
>
> STA <---f0---> Node A <---f0---> Node B   f0=2412GHz
>
> Node A and node B were running latest OpenWRT trunk, AR9280 chipset.
> I was injecting 30Mbps of UDP iperf traffic from STA to Node B.
> I was facing a connection stuck issue on Node B side because it
> reports a lot of decrypt errors
> and since decrypt_error flag sets to true, it tries to decrypt an
> already decrypted frame with ieee80211_aes_ccm_decrypt. Setting
> decrypt_error to false at beginning of ath_rx_tasklet cycle
> the connection is definitely more stable avoiding waste of CPU time.

Can you resubmit with all this information and also what Felix
mentioned and also also add:

Cc: stable@vger.kernel.org

as part of your commit log message (note: commit log, not e-mail).

  Luis