From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49998) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1djhdU-0001xB-Ev for qemu-devel@nongnu.org; Mon, 21 Aug 2017 04:00:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1djhdQ-00045T-81 for qemu-devel@nongnu.org; Mon, 21 Aug 2017 04:00:36 -0400 Received: from indium.canonical.com ([91.189.90.7]:52275) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1djhdQ-00045H-2H for qemu-devel@nongnu.org; Mon, 21 Aug 2017 04:00:32 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.76 #1 (Debian)) id 1djhdP-0000vm-3w for ; Mon, 21 Aug 2017 08:00:31 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 18B7E2E80C7 for ; Mon, 21 Aug 2017 08:00:31 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Mon, 21 Aug 2017 07:47:51 -0000 From: Thomas Huth <1054180@bugs.launchpad.net> Reply-To: Bug 1054180 <1054180@bugs.launchpad.net> Sender: bounces@canonical.com References: <20120921161324.22633.34633.malonedeb@chaenomeles.canonical.com> Message-Id: <150330167165.17444.7297182278064985891.malone@gac.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 1054180] Re: DNS activity in slirp (user networking) mode quickly depletes file descriptors and crashes qemu List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Triaging old bug tickets ... can you still reproduce this problem with the latest version of QEMU (currently v2.9 or a release candidate of 2.10)? ** Changed in: qemu Status: New =3D> Incomplete -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1054180 Title: DNS activity in slirp (user networking) mode quickly depletes file descriptors and crashes qemu Status in QEMU: Incomplete Bug description: Hi, we have encountered quite some trouble with filedescriptor depletion of the qemu process. We have figured out that it can be demonstrated easily by doing a lot of DNS queries inside the VM -- in our real world scenario this is caused by running centos network install with a fast mirror. This situation is further problematic because qemu can't handle fd deplet= ion very well: 1) if ulimit is 1024 then qemu hangs in infinite loop whenever it tries t= o open the 1025th fd 2) setting ulimit >1024 does not help that much because qemu uses select = and max. fd set size is 1024 per default =3D> qemu crashes because of buffe= r overflow in select() 3) setting ulimit > 1024 AND recompiling with large enough fd set size AN= D disabling gcc's fortify source seems to work, but that's really just a ho= t-fix The problem can be replicated quite easily by running something like while :; do echo >/dev/udp/10.0.2.3/53; done inside a Linux VM -- crash comes very soon. This problem is present in current qemu (1.2.0) and in earlier as well. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1054180/+subscriptions