From owner-freebsd-current Mon Sep 24 12:34:23 2001 Delivered-To: freebsd-current@freebsd.org Received: from mail.wrs.com (unknown-1-11.windriver.com [147.11.1.11]) by hub.freebsd.org (Postfix) with ESMTP id 2ADA037B408 for ; Mon, 24 Sep 2001 12:34:05 -0700 (PDT) Received: from laptop.baldwin.cx ([147.11.46.209]) by mail.wrs.com (8.9.3/8.9.1) with ESMTP id MAA02033; Mon, 24 Sep 2001 12:33:50 -0700 (PDT) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <20010923204929.A11867@freebie.xs4all.nl> Date: Mon, 24 Sep 2001 12:33:32 -0700 (PDT) From: John Baldwin To: Wilko Bulte Subject: Re: Seen this lock order reversal? Cc: Garrett Wollman , current@FreeBSD.org Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 23-Sep-01 Wilko Bulte wrote: > On Thu, Sep 20, 2001 at 07:40:52PM +0200, Wilko Bulte wrote: >> On Wed, Sep 19, 2001 at 01:32:28PM -0700, John Baldwin wrote: >> > >> > On 19-Sep-01 Wilko Bulte wrote: >> > > On Tue, Sep 18, 2001 at 03:01:25PM -0700, John Baldwin wrote: >> >> ... >> >> > >> p_flag to p_sflag which changed its locking semantics.) >> > > >> > > Another one, on a -current from yesterday, on -alpha: >> > > >> > > lock order reversal >> > > 1st 0xfffffc00007fcef0 clk @ ../../../alpha/alpha/clock.c:702 >> > > 2nd 0xfffffc00007f65d8 callout @ ../../../kern/kern_timeout.c:225 >> > > ds10# >> > >> > Hmm, ok, that one is new and is a problem. Can you turn on WITNESS_DDB >> > (it's >> > available as the debug.witness_ddb sysctl and loader variableas well) and >> > then >> > get me a traceback in ddb? >> >> I built a GENERIC with WITNESS_DDB. Sofar (of course... :-/ ) no >> reproduction of the problem. I'm running buildworlds, any other good >> suggestions to help trigger it are welcome > > Bah. I cannot reproduce this on my DS10. > > Is there any reason to assume that specifying CPUTYPE ev56 has any > influence on the lock order reversal? By default world is built with > ev4, but I have gone to ev56 now. Rumor has it that results in 'less > buggy' code. No. Hmmm. You didn't have any KTR traces enabled did you? Hmm, that first one is in sysbeep() (the clk one) Ah! if (!beeping) { /* enable counter2 output to speaker */ if (pitch) outb(IO_PPI, inb(IO_PPI) | 3); beeping = period; timeout(sysbeepstop, (void *)NULL, period); } This is the problem code. Hmmm. The i386 code seems b0rked. It doesn't have enough locks! Eck. hmm, the pc98 code doesn't even _use_ the mutex but still depends on disable/enable intr. Eek. I'll work at this later on today. -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message