From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261544AbVFEKCg (ORCPT ); Sun, 5 Jun 2005 06:02:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261545AbVFEKCg (ORCPT ); Sun, 5 Jun 2005 06:02:36 -0400 Received: from ms.iem.uni-duisburg-essen.de ([132.252.150.1]:43683 "EHLO pilz.exp-math.uni-essen.de") by vger.kernel.org with ESMTP id S261544AbVFEKCb convert rfc822-to-8bit (ORCPT ); Sun, 5 Jun 2005 06:02:31 -0400 Subject: IRQ exception upon networking with many vifs/bridges (using Xen) From: Birger =?ISO-8859-1?Q?T=F6dtmann?= To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Date: Sun, 05 Jun 2005 11:38:43 +0200 Message-Id: <1117964324.2494.15.camel@lomin> Mime-Version: 1.0 X-Mailer: Evolution 2.2.1.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, (- this is sort of crossposting from Xen mailing lists, because I do not know whether this is very Xen specific as the domain0 linux kernel is crashing with a 'fatal exception in interrupt' - see below for details.) I try to build experimental networks with Linux and Xen and stumbled over the problem that for many bridge/vif devices, there are not as much NR_IRQS available as needed (relevant posting on Xen mailling lists here: http://lists.xensource.com/archives/html/xen-users/2005-04/msg00447.html) Fortunately, Xen-3.0-devel increased NR_PIRQS and NR_DYNIRQS. It is now possible to get a virtual test network up and running with 20 nodes and approx. 120 interfaces, without problems at first. The vifs are wired to ~60 bridge interfaces, 2 vifs each. Kernel version is 2.6.11, Xen version is xen-unstable (a.k.a 3.0-devel) as of May 31. The problem: when allowing free packet delivery within the network by issueing a sysctl -w net.bridge.bridge-nf-call-iptables=0 (which was until then set to 1 and my iptables rules blocked all traffic), the whole machine freezes after a very short time (immediately to 2-3 seconds), apparently when the first packet is traveling through the network. No output, kernel oops, nothing to see, and magic sysrq gone as well(!). This behaviour is deterministic. I had quite some difficulties getting more information - what I finally did was to set the sysctl *before* starting the domUs. Funnily, nothing happend after starting the first 10-12 nodes, but after "xm create"ing one or two more nodes, the system oopsed with at least some info, but sysrq gone as well. So I wrote it down on a peace of paper ;-) , hopefully someone can make sense of it. I'd happily debug this further but need some hints on where to begin... Stack: 00000000 d06cea20 2f001020 c8b04780 c0403f1c c028cbfa 0002f001 0000000d ffffffff 08b78020 00000052 00000001 00000028 0000005e 00008b85 d21fe000 00000006 c0457824 0000011d c0453240 00283d58 e01c3a6e c0403cec da6bccd0 Call Trace: [] show_stack+0x80/0x96 [] show_registers+0x15a/0x1d1 [] die+0x106/0x1c4 [] do_invalid_op+0xb5/0xbf [] error_code+0x2b/0x30 [] net_rx_action+0x484/0x4df [] tasklet_action+0x7b/0xe0 [] __do_softirq+0x6f/0xef [] do_softirq+0x7f/0x97 [] irq_exit+0x3a/0x3c [] do_IRQ+0x25/0x2c [] evtchn_do_upcall+0x62/0x82 [] hypervisor_callback+0x2c/0x34 [] cpu_idle+0x33/0x41 [] start_kernel+0x196/0x1e8 [] 0xc010006c Code: 08 a8 75 30 83 c4 5b 5e 5f 5d c3 bb 01 00 00 00 31 f6 b8 0c 00 00 00 bf f0 7f 00 00 8d 4d 08 89 da cd 82 83 e8 01 2e 74 8e <0f> 0b 66 00 2c 7a 35 c0 eb 84 e8 f8 b1 09 00 eb c9 e8 f6 98 e7 <0>Kernel panic - not syncing: Fatal exception in interrupt System data: * gcc-Version 3.4.3-20050110 (Gentoo Linux 3.4.3.20050110-r2, ssp-3.4.3.20050110-0, pie-8.7.7) * Pentium 4 Mobile CPU 1.60GHz GenuineIntel GNU/Linux (Dell Inspiron 8200) Thanks for some suggestions & regards, -- Birger Tödtmann Technik der Rechnernetze, Institut für Experimentelle Mathematik Universität Duisburg-Essen, Campus Essen email:btoedtmann@iem.uni-due.de skype:birger.toedtmann pgp:0x6FB166C9