From owner-freebsd-stable@FreeBSD.ORG Tue Sep 30 10:40:28 2008 Return-Path: Delivered-To: freebsd-stable@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 13ECB106568A; Tue, 30 Sep 2008 10:40:27 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id E340F8FC17; Tue, 30 Sep 2008 10:40:26 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [65.122.17.41]) by cyrus.watson.org (Postfix) with ESMTP id 91FAD46B03; Tue, 30 Sep 2008 06:40:26 -0400 (EDT) Date: Tue, 30 Sep 2008 11:40:26 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Gavin Atkinson In-Reply-To: <1222770746.29968.6.camel@buffy.york.ac.uk> Message-ID: References: <20080929221408.54e6a03a.lehmann@ans-netz.de> <1222770746.29968.6.camel@buffy.york.ac.uk> User-Agent: Alpine 1.10 (BSF 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Cc: freebsd-stable@FreeBSD.org, Oliver Lehmann Subject: Re: system hangup - I'm lost X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Sep 2008 10:40:28 -0000 On Tue, 30 Sep 2008, Gavin Atkinson wrote: > On Mon, 2008-09-29 at 22:14 +0200, Oliver Lehmann wrote: > >> Any idea what I could do to shed some more light on this behaviour? >> Why it is happening and what really is causing it? >> Would enabling the kernel debugger really help here? I mean the system >> is really hanging up - except ping response it is not responding to >> anything except the reset switch ;) > > If it's responding to ping, you should be able to get into the debugger. > Compile it in, along with "options WITNESS" and "options WITNESS_SKIPSPIN", > and press ctrl-alt-escape when the machine next hangs. > > From there, it should hopefully be possible to get more info. It's been a > long time since I've used the debugger under 6.x so some of the more useful > commands may not exist, but the output of at least "sh locks", "sh alllocks" > and "bt" on any processes that seem to be holding locks. Also "sh pcpu" and > "ps" will help to determine exactly what was running at the time. "show lockedvnods" is also quite useful if the problem originates in the file system, as it lists vnodes that have been locked, and by which threads. Robert N M Watson Computer Laboratory University of Cambridge