Date: Tue, 31 Jul 2001 15:11:38 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: Vincent Poy <vince@oahu.WURLDLINK.NET> Cc: current@FreeBSD.org, Kris Kennaway <kris@obsecurity.org>, Sheldon Hearn <sheldonh@starjuice.net> Subject: Re: -current lockups Message-ID: <XFMail.010731151138.jhb@FreeBSD.org> In-Reply-To: <20010731120618.A87252-100000@oahu.WURLDLINK.NET>
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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 <jhb@FreeBSD.org> -- 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
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