From owner-freebsd-current@FreeBSD.ORG Tue Feb 22 22:18:11 2005 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 897BA16A4E7 for ; Tue, 22 Feb 2005 22:18:11 +0000 (GMT) Received: from mail25.sea5.speakeasy.net (mail25.sea5.speakeasy.net [69.17.117.27]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4183D43D53 for ; Tue, 22 Feb 2005 22:18:11 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: (qmail 24043 invoked from network); 22 Feb 2005 22:18:11 -0000 Received: from server.baldwin.cx ([216.27.160.63]) (envelope-sender )AES256-SHA encrypted SMTP for ; 22 Feb 2005 22:18:10 -0000 Received: from [10.50.40.202] (gw1.twc.weather.com [216.133.140.1]) (authenticated bits=0) by server.baldwin.cx (8.13.1/8.13.1) with ESMTP id j1MMHvg8017494; Tue, 22 Feb 2005 17:18:05 -0500 (EST) (envelope-from jhb@FreeBSD.org) From: John Baldwin To: freebsd-current@FreeBSD.org Date: Tue, 22 Feb 2005 15:52:37 -0500 User-Agent: KMail/1.6.2 References: <20050206134113.GA77071@peter.osted.lan> <200502081448.43759.jhb@FreeBSD.org> <20050208201437.GA46141@peter.osted.lan> In-Reply-To: <20050208201437.GA46141@peter.osted.lan> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200502221552.37300.jhb@FreeBSD.org> X-Spam-Status: No, score=-102.8 required=4.2 tests=ALL_TRUSTED, USER_IN_WHITELIST autolearn=failed version=3.0.2 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on server.baldwin.cx Subject: Re: Deadlock with option FULL_PREEMPTION X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Feb 2005 22:18:11 -0000 On Tuesday 08 February 2005 03:14 pm, Peter Holm wrote: > On Tue, Feb 08, 2005 at 02:48:43PM -0500, John Baldwin wrote: > > On Tuesday 08 February 2005 02:08 pm, Peter Holm wrote: > > > On Tue, Feb 08, 2005 at 01:17:40PM -0500, John Baldwin wrote: > > > > On Sunday 06 February 2005 08:41 am, Peter Holm wrote: > > > > > With GENERIC HEAD from Feb 5 09:19 UTC + FULL_PREEMPTION + > > > > > mpsafe_vfs = 1 I ran into what appears to be the same deadlock > > > > > twice. This is the first one: > > > > > http://www.holm.cc/stress/log/cons114.html > > > > > > > > What is the deadlock exactly? > > > > > > top froze, console login froze after giving login name, but I > > > could ping the box. > > > > So it could be livelock rather than deadlock if interrupt processing > > still works (ping). > > > > > > It looks like lots of threads banging on fork() > > > > and that they are all waiting on an exclusive lock of allproc_lock > > > > while holding a shared lock of proctree_lock (except for the 1 thread > > > > currently doing a fork that is on a run queue because it was > > > > preempted by IRQ 0 which kicked off softclock). Can you get 'ps' > > > > output? > > > > > > Yes: > > > > Well, kmail butchered this in my reply so I won't quote any of it, but it > > does seem that the process everyone is waiting on is runnable. I'm not > > sure if there's anything you can do to recover from the livelock, but the > > livelock is holding up all the forks so you can't get a login process to > > fork a shell, etc. (At least not quickly apparently). > > Oh, recovery is not an issue. I'm stress testing, but this > problem does seem to prevent finding other kernel problems > with FULL_PREEMPTION. I'll just go back to testing without this > option. Thanx for looking at this. Can you try doing this but with machdep.cpu_idle_hlt set to off as per my other posting to current@ several days ago? -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org