From owner-freebsd-current@FreeBSD.ORG Tue Oct 5 21:34:00 2004 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 EC97916A4CE; Tue, 5 Oct 2004 21:34:00 +0000 (GMT) Received: from spxau01.smeglobalnet.net (spxau01.smeglobalnet.net [203.57.65.8]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2F1AF43D1F; Tue, 5 Oct 2004 21:33:58 +0000 (GMT) (envelope-from andy@bradfieldprichard.com.au) Received: from bpgate.speednet.com.au ([203.41.15.9]) by spxau01.smeglobalnet.net with Microsoft SMTPSVC(5.0.2195.6713); Wed, 6 Oct 2004 07:12:28 +1000 Received: from bpgate.speednet.com.au (localhost [127.0.0.1]) i95LCRRx035594; Wed, 6 Oct 2004 07:12:28 +1000 (EST) (envelope-from andy@bradfieldprichard.com.au) Received: from localhost (andy@localhost)i95LCRLj035591; Wed, 6 Oct 2004 07:12:27 +1000 (EST) (envelope-from andy@bradfieldprichard.com.au) X-Authentication-Warning: bpgate.speednet.com.au: andy owned process doing -bs Date: Wed, 6 Oct 2004 07:12:27 +1000 (EST) From: Andy Farkas X-X-Sender: andy@bpgate.speednet.com.au To: Brian Fundakowski Feldman In-Reply-To: <20041003075303.GG1034@green.homeunix.org> Message-ID: <20041006064726.W35438@bpgate.speednet.com.au> References: <20040924230425.GB1164@green.homeunix.org> <200409271635.44017.jhb@FreeBSD.org> <20041003075303.GG1034@green.homeunix.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-OriginalArrivalTime: 05 Oct 2004 21:12:29.0037 (UTC) FILETIME=[055B01D0:01C4AB20] cc: freebsd-current@freebsd.org Subject: Re: panic: APIC: Previous IPI is stuck 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, 05 Oct 2004 21:34:01 -0000 On Sun, 3 Oct 2004, Brian Fundakowski Feldman wrote: > On Sat, Oct 02, 2004 at 02:02:01AM -0400, Brian Fundakowski Feldman wrote: >> Okay, I just got another one of these, exactly the same as that one but >> for the fact that the softclock() interrupt was specifically locking >> Giant instead of the interrupt thread loop. So the other CPU owned >> Giant at the time and the scheduling CPU is trying to acquire it and >> interrupted by needing to run the statclock(). >> >> This is way too coincidental to ignore. >> >> SCHED_ULE is far too complex for me to understand much of right now; >> what prevents sched_clock() from calling kseq_assign() multiple times >> per CPU? Are we _absolutely_100%_certain_ that functionality works >> correctly? > > Ping... adding Jeff... I really wish I understood SCHED_ULE, because it > seems entirely plausible it's trying to send two IPIs, the first of > which would get blocked waiting for the held sched_lock, and the second > of which would never have its interrupt serviced because the first one > blocked on sched_lock would have interrupts disabled and would remain > unable to respond to an IPI... I can confirm that 5.3-BETA7 with SCHED_4BSD is rock solid, but with SCHED_ULE a panic is easily triggered (by make -j4 buildworld). -andyf