From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gavin McCullagh Subject: possible bug in tcp_probe Date: Tue, 13 Nov 2007 11:26:15 +0000 Message-ID: <20071113112615.GA7491@nuim.ie> Reply-To: Gavin McCullagh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT To: netdev@vger.kernel.org Return-path: Received: from banyan.nuim.ie ([149.157.1.4]:59512 "EHLO mango.nuim.ie" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751834AbXKMM0J (ORCPT ); Tue, 13 Nov 2007 07:26:09 -0500 Content-disposition: inline Received: from boing.hamilton.local ([149.157.192.252]) by mango.nuim.ie (Sun Java(tm) System Messaging Server 6.3-4.01 (built Aug 3 2007; 32bit)) with ESMTP id <0JRF00NN5ZRI2T70@mango.nuim.ie> for netdev@vger.kernel.org; Tue, 13 Nov 2007 11:26:06 +0000 (GMT) Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hi, I'm using linux v2.6.22.6 and tcp_probe with a couple of small modifications[1]. Even with moderately large numbers of flows (16 on the one machine) and increasingly as I monitor more flows than that, I get strange overflow problems such as this one: 74.259589763 192.168.2.1 36988 192.168.3.5 5001 0x679c23dc 0x679bc3b4 18 13 9114624 78 76 10000 0 64 74.260590660 192.168.2.1 44261 192.168.3.5 5006 0x573bb3ed 0x573b700d 13 9 5254144 155 127 10000 0 64 74.261607478 192.168.2.1 44261 192.168.3.5 5006 0x588.066586741 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cf577 2 3 13090816 443 15818 10000 0 64 88.066690797 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cfb1f 3 3 13092864 2365 15818 10000 0 64 88.067625714 192.168.2.1 59385 192.168.3.5 5012 0x411c1090 0x411bd258 12 9 14578688 2807 15812 10000 0 64 As you can see the third line has been truncated as well as the next roughly 14 seconds of data after which data continues writing as usual. I don't think my small changes are causing this but perhaps I'm wrong. Does anyone know what might be causing the above? Many thanks for any ideas, Gavin [1] I have slightly modified tcp_probe to print out information for a range of ports (instead of one port or all) and to print info from the congestion avoidance inet_csk_ca struct. This adds a couple of extra fields to the end. If either of these are of interest as patches I'll happily submit them.