From owner-freebsd-current Tue Jul 31 15:11:50 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 33CBE37B406 for ; Tue, 31 Jul 2001 15:11:47 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: from laptop.baldwin.cx (john@[147.11.46.217]) by mail.wrs.com (8.9.3/8.9.1) with ESMTP id PAA07705; Tue, 31 Jul 2001 15:11:37 -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: <20010731120618.A87252-100000@oahu.WURLDLINK.NET> Date: Tue, 31 Jul 2001 15:11:38 -0700 (PDT) From: John Baldwin To: Vincent Poy Subject: Re: -current lockups Cc: current@FreeBSD.org, Kris Kennaway , Sheldon Hearn 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 31-Jul-01 Vincent Poy wrote: > On Tue, 31 Jul 2001, John Baldwin wrote: > >> >> On 31-Jul-01 Vincent Poy wrote: >> > On Tue, 31 Jul 2001, John Baldwin wrote: >> >> > root@pele [9:29pm][/usr/temp] >> >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: lock order reversal >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: lock order reversal >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: 1st 0xd92fea9c process lock @ >> >> > /usr/src/sys/vm/vm_glue.c:469 >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: 1st 0xd92fea9c process lock @ >> >> > /usr/src/sys/vm/vm_glue.c:469 >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: 2nd 0xc118dfb0 lockmgr >> >> > interlock >> >> > @ /usr/src/sys/kern/kern_lock.c:239 >> >> > Jul 28 21:29:40 pele /boot/kernel/kernel: 2nd 0xc118dfb0 lockmgr >> >> > interlock >> >> > @ /usr/src/sys/kern/kern_lock.c:239 >> >> >> >> This is due to the way that lockmgr locks are implemented unfortunately, >> >> and >> >> will be fixed when vm maps switch to sx locks instead of lockmgr locks. >> > >> > Interesting. Is there a workaround so it just reboots instead of >> > freezing? Also, I noticed that you committed some changes to the kernel, >> > is that supposed to help it any? >> >> There is currently not a workaround. The changes committed fix other >> things, >> but not this problem. I haven't actually seen this lock order cause a >> freeze >> before to be honest. > > Yeah, that's the weird part... I thought adding a DDB_UNATTENDED > as a option would atleast make it reboot or something... Well, since it is a lock order reversal, there is the chance of it resulting in a deadlock though the chances of that on a UP machine would be very, very rare indeed. The reversal in question is triggered when we swap a process out. -- 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