Re: 2.6.23-rc8-mm2 - tcp_fastretrans_alert() WARNING

From: Cedric Le Goater
Date: Sat Sep 29 2007 - 10:57:29 EST

Ilpo Järvinen wrote:
> On Fri, 28 Sep 2007, Ilpo Järvinen wrote:
>> On Fri, 28 Sep 2007, Cedric Le Goater wrote:
>>> I just found that warning in my logs. It seems that it's been
>>> happening since rc7-mm1 at least.
>>> WARNING: at /home/legoater/linux/2.6.23-rc8-mm2/net/ipv4/tcp_input.c:2314 tcp_fastretrans_alert()
>>> Call Trace:
>>> <IRQ> [<ffffffff8040fdc3>] tcp_ack+0xcd6/0x1894
>>> ...snip...
>> ...Thanks for the report, I'll have look what could still break
>> fackets_out...
> I think this one is now clear to me, tcp_fragment/collapse adjusts
> fackets_out (incorrectly) also for reno flow when there were some dupACKs
> that made sacked_out != 0. Could you please try if patch below proves all
> them to be of non-SACK origin... In case that's true, it's rather
> harmless, I'll send a fix on Monday or so (this would anyway be needed)...
> If you find out that them occur with SACK enabled flow, that would be
> more interesting and requires more digging...

I'm trying now to reproduce this WARNING.

It seems that the n/w behaves differently during the week ends. Probably
taking a break.

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