From: Ben Greear <greearb@candelatech.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: 3.9.5+: Crash in tcp_input.c:4810.
Date: Mon, 08 Jul 2013 12:59:08 -0700 [thread overview]
Message-ID: <51DB1A0C.3080807@candelatech.com> (raw)
In-Reply-To: <1373310119.4979.119.camel@edumazet-glaptop>
On 07/08/2013 12:01 PM, Eric Dumazet wrote:
> On Mon, 2013-07-08 at 11:30 -0700, Ben Greear wrote:
>> On 07/08/2013 11:21 AM, Eric Dumazet wrote:
>>> On Mon, 2013-07-08 at 10:23 -0700, Ben Greear wrote:
>>>
>>>> We ran a 5+ day test using un-modified 3.10 kernel and did not trigger
>>>> the bug.
>>>
>>> Using wired ethernet only, or any kind of adapters, including ath9k ?
>>
>> Exact same hardware and configuration:
>>
>> ath9k, around 240 wifi
>> stations trying to connect to APs that can handle a bit less
>> than 240 total, starting TCP traffic when stations are connected.
>> It appears that the constant churn of stations going up and down
>> is key, but of course that is par for the course, especially in
>> the wifi stack.
>>
>> Some of our local wifi patches make the system work considerably faster when
>> we have hundreds of wifi stations, so timing will be different on upstream
>> kernels, and of course we could have bugs :)
>
> There is this thing in ath9k about aggregating two frags
>
> drivers/net/wireless/ath/ath9k/recv.c line 1298 contains :
>
> RX_STAT_INC(rx_frags);
>
> Could you check these stats (I do not know if they are reported by
> ethtool -S or another debugging facility) and check if rx_frags is ever
> increasing ?
They are in debugfs, and they appear to increase fairly often, for
instance:
[root@lec2010-ath9k-1 lanforge]# cat /debug/ieee80211/wiphy0/ath9k/recv|tail -5
RX-Pkts-All : 288009442
RX-Bytes-All : 4067932166
RX-Beacons : 14826735
RX-Frags : 3944
RX-Spectral : 0
I don't have the stats from the system that reproduced the bug
(it has been rebooted), but if I do see the bug again, I'll
grab the rx-frags and other stats just in case it shows
some anomaly.
Thanks,
Ben
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
next prev parent reply other threads:[~2013-07-08 19:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-17 18:08 3.9.5+: Crash in tcp_input.c:4810 Ben Greear
2013-06-17 18:17 ` Eric Dumazet
2013-06-21 19:26 ` Ben Greear
2013-07-01 18:10 ` Ben Greear
2013-07-03 1:04 ` Eric Dumazet
2013-07-03 3:21 ` Ben Greear
2013-07-03 4:41 ` Eric Dumazet
2013-07-03 4:49 ` Ben Greear
2013-07-03 5:02 ` Eric Dumazet
2013-07-08 17:23 ` Ben Greear
2013-07-08 18:21 ` Eric Dumazet
2013-07-08 18:30 ` Ben Greear
2013-07-08 19:01 ` Eric Dumazet
2013-07-08 19:59 ` Ben Greear [this message]
2013-07-08 20:10 ` Eric Dumazet
2013-07-08 20:17 ` Ben Greear
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