Message-ID: <5037ABE2.2020407@lwfinger.net> (sfid-20120824_182946_087349_5C5E2316)
Date: Fri, 24 Aug 2012 11:29:22 -0500
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: Eric Dumazet <eric.dumazet@gmail.com>
CC: Neal Cardwell <ncardwell@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	John W Linville <linville@tuxdriver.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Regression associated with commit c8628155ece3 - "tcp: reduce
 out_of_order memory use"
References: <50345B12.1050600@lwfinger.net>  <1345612503.5158.566.camel@edumazet-glaptop>  <50355021.7000408@lwfinger.net> <1345694593.5904.87.camel@edumazet-glaptop>  <50369925.3050705@lwfinger.net>  <1345757200.5904.1890.camel@edumazet-glaptop> <50378B35.80307@lwfinger.net>  <1345820142.4824.1.camel@edumazet-laptop> <5037A292.1020801@lwfinger.net> <1345824094.19483.9.camel@edumazet-glaptop>
In-Reply-To: <1345824094.19483.9.camel@edumazet-glaptop>
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Sender: linux-wireless-owner@vger.kernel.org

On 08/24/2012 11:01 AM, Eric Dumazet wrote:
> On Fri, 2012-08-24 at 10:49 -0500, Larry Finger wrote:
>
>> There is nothing in kernel log when it happens. The file STRACE is attached.
>>
>
> So there is indeed a corruption. What was the driver you used in this
> case ?

The only driver that shows this problem is r8712u. One thought that I just had 
is that this driver does not use mac80211, which is why it is in staging. 
Instead it uses a Realtek soft MAC layer derived from the obsolete softmac 
driver that was in the kernel in the 2.6.20 time frame. That means that none of 
the skbs have ever been cloned by any part of the wireless code.

Larry