Date: Tue, 31 Jul 2001 12:16:32 -1000 (HST) From: Vincent Poy <vince@oahu.WURLDLINK.NET> To: John Baldwin <jhb@FreeBSD.org> Cc: <current@FreeBSD.org>, Kris Kennaway <kris@obsecurity.org>, Sheldon Hearn <sheldonh@starjuice.net> Subject: Re: -current lockups Message-ID: <20010731121418.I87252-100000@oahu.WURLDLINK.NET> In-Reply-To: <XFMail.010731151138.jhb@FreeBSD.org>
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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. Yep, it's so rare that nothing can trigger it except for passwd and chpass after they successfully exit and do the following successfully... passwd: updating the database... passwd: done Even vipw doesn't trigger it which I thought it would as it would do all the users rather than just one. Cheers, Vince - vince@WURLDLINK.NET - Vice President ________ __ ____ Unix Networking Operations - FreeBSD-Real Unix for Free / / / / | / |[__ ] WurldLink Corporation / / / / | / | __] ] San Francisco - Honolulu - Hong Kong / / / / / |/ / | __] ] HongKong Stars/Gravis UltraSound Mailing Lists Admin /_/_/_/_/|___/|_|[____] Almighty1@IRC - oahu.DAL.NET Hawaii's DALnet IRC Network Server Admin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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