From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leszek Urbanski Subject: BUG - qdev - partial loss of network connectivity Date: Wed, 22 Sep 2010 13:42:01 +0200 Message-ID: <20100922114201.GA25638@moo.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 To: kvm@vger.kernel.org Return-path: Received: from moo.pl ([217.149.240.132]:43273 "EHLO moo.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751703Ab0IVLtK (ORCPT ); Wed, 22 Sep 2010 07:49:10 -0400 Received: from localhost (localhost [127.0.0.1]) by moo.pl (Postfix) with ESMTP id 7A255183FB for ; Wed, 22 Sep 2010 13:42:08 +0200 (CEST) Received: from moo.pl ([127.0.0.1]) by localhost (moo.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id m8L5uUMH5t8B for ; Wed, 22 Sep 2010 13:42:02 +0200 (CEST) Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Hi, host and guest kernel: 2.6.32.22 arch: amd64 qemu-kvm: 0.12.5 and 0.13.0-rc1 How to reproduce: copy a large (few hundred MB) file to an NFS mount (guest is the client), using qdev syntax for virtio: -device virtio-net-pci,netdev=tap1,mac=ab:cd:ef:01:23:45 \ -netdev type=tap,id=tap1,ifname=tap1 all NFS mounts immediately stall and processes go into D state and are stuck on nfs_wait_bit_uninterruptible. There is no further communication between the client and the server. It occurs with UDP and TCP mounts. That same guest, when switched to the old -net/-net syntax: -net nic,vlan=0,model=virtio,name=eth0,macaddr=ab:cd:ef:01:23:45 \ -net tap,vlan=0,ifname=tap1 works fine. It also works fine on bare metal. I can reproduce the problem every time within 10 minutes with qdev. -- Leszek "Tygrys" Urbanski, SCSA, SCNA "Unix-to-Unix Copy Program;" said PDP-1. "You will never find a more wretched hive of bugs and flamers. We must be cautious." -- DECWARS http://cygnus.moo.pl/ -- Cygnus High Altitude Balloon