Re: Possible BUG in IPv4 TCP window handling, all recent 2.4.x/2.6.x kernels

[Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>]

Hello!

> >Anyway, ignoring this puzzle, the following patch for 2.4 should help.
> >
> >
> >--- net/ipv4/tcp_input.c.orig	2003-02-20 20:38:39.000000000 +0300
> >+++ net/ipv4/tcp_input.c	2005-09-02 22:28:00.845952888 +0400
> >@@ -343,8 +343,6 @@
> >			app_win -= tp->ack.rcv_mss;
> >		app_win = max(app_win, 2U*tp->advmss);
> >
> >-		if (!ofo_win)
> >-			tp->window_clamp = min(tp->window_clamp, app_win);
> >		tp->rcv_ssthresh = min(tp->window_clamp, 2U*tp->advmss);
> >	}
> >}
> 
> I'm very happy to report that the above patch, applied to 2.6.12.6, seems 
> to have cured the TCP window problem we were experiencing.

Good. I think the patch is to be applied to all mainstream kernels.

The only obstacle is the second report by Guillaume Autran <gautran@mrv.com>,
which has some allied characteristics, but after analysis it is something
impossible, read, cryptic and severe bug. :-( I did not get a responce
to the last query, so the investigation stalled.

Alexey
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