From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750810AbXCDEHX (ORCPT ); Sat, 3 Mar 2007 23:07:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750910AbXCDEHX (ORCPT ); Sat, 3 Mar 2007 23:07:23 -0500 Received: from mcr-smtp-002.bulldogdsl.com ([212.158.248.8]:1465 "EHLO mcr-smtp-002.bulldogdsl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbXCDEHW (ORCPT ); Sat, 3 Mar 2007 23:07:22 -0500 X-Spam-Abuse: Please report all spam/abuse matters to abuse@bulldogdsl.com From: Alistair John Strachan To: linux-kernel@vger.kernel.org Subject: 2.6.20, Java, unresponsive userspace Date: Sun, 4 Mar 2007 04:07:07 +0000 User-Agent: KMail/1.9.5 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703040407.07234.s0348365@sms.ed.ac.uk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I've had some problems with 2.6.20 (but also with earlier kernels, like Debian's 2.6.18) where one of the users on our system, running a Java6 application, is somehow able to make the userspace on the machine totally unresponsive, denying all remote _and_ local access to the machine. - The AMD64 port of Linux and Java are in use - The process runs as an unprivileged user - The OOM killer doesn't kick in - No swap is enabled on the machine - I'm told that the program doesn't fork bomb (but I've not got a reproducible test case yet) - The program is able to deny service even to a getty login. If I SAK the machine, init respawns getty and everything is fine again. alistair@clarent:~$ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited max nice (-e) 0 file size (blocks, -f) unlimited pending signals (-i) unlimited max locked memory (kbytes, -l) 1000 max memory size (kbytes, -m) 1000 open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) unlimited max rt priority (-r) 0 stack size (kbytes, -s) 2048 cpu time (seconds, -t) unlimited max user processes (-u) 100 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited Any ideas with how to proceed for debugging this issue? -- Cheers, Alistair. Final year Computer Science undergraduate. 1F2 55 South Clerk Street, Edinburgh, UK.