From owner-freebsd-current@FreeBSD.ORG Fri Jan 24 14:52:06 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 643B6DF5 for ; Fri, 24 Jan 2014 14:52:06 +0000 (UTC) Received: from mail-ve0-x236.google.com (mail-ve0-x236.google.com [IPv6:2607:f8b0:400c:c01::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 1F41E1470 for ; Fri, 24 Jan 2014 14:52:06 +0000 (UTC) Received: by mail-ve0-f182.google.com with SMTP id jy13so1984761veb.41 for ; Fri, 24 Jan 2014 06:52:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=+7T7Gfalg1fhZpOXrgMunDzTQjR90U9NC2jI6haDSNE=; b=G7l3XwOnhPp3vSgn6d0doLMPxIoI74x+XIkSZQYFz1WtGOPU/BH5rnVAw78tG70kYB IiSPzzYVSZunuQfZeRYXFhG28SQgS8w+k8woOQMypA2ufktcHAiSeX6Hx+eyAGr8JxS8 9W5FDFHJwvayIeO1WIq/pLTYyK28wJsFRh/0/ChEBRxyCD9FNQLW6bZYk5iMG7IiC7La qd+OEe2zmI+Ub84dCNtgU93IGL92rsYYkJslbfcxw5HmxG7dbWeLoqMqcFvBZDNcuu1+ QP9wifGlR6Gp3R/8Ehgk1yCYOzNdsV6AFdLy819f2SGoHSNfL35MH6rnd+JZ1Otbakq6 Rn2Q== MIME-Version: 1.0 X-Received: by 10.220.139.136 with SMTP id e8mr4910238vcu.34.1390575125226; Fri, 24 Jan 2014 06:52:05 -0800 (PST) Received: by 10.220.168.135 with HTTP; Fri, 24 Jan 2014 06:52:05 -0800 (PST) In-Reply-To: References: Date: Fri, 24 Jan 2014 09:52:05 -0500 Message-ID: Subject: Re: lock order reversals w/ backtrace From: Thomas Hoffmann To: freebsd-current Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: Hans Petter Selasky X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.17 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: Fri, 24 Jan 2014 14:52:06 -0000 On Thu, Jan 23, 2014 at 11:49 AM, Hans Petter Selasky < hans.petter.selasky@bitfrost.no> wrote: > Hi, > > Can you see if you can snap some keywords of the backtraces, like usb_xxx usbdx_xxx cam scsi or something like that. > > Else I believe there are some sysctl options to prevent the final reboot somehow so that you can write down the messages. > > --HPS > > > -----Original message----- > > From:Thomas Hoffmann > > Sent: Thursday 23rd January 2014 17:15 > > To: freebsd-current > > Subject: lock order reversals w/ backtrace > > > > A few days ago I started running 11.0-CURRENT at r260971 for the first time. > > > > The last couple of times I shutdown my system I noticed 2 or 3 short "lock > > order reversal" messages with accompanying backtraces scroll by. Do these > > messages represent a problem that I should report or can I ignore them as > > debug in nature? If I should report them, how or where do these messages > > get logged? I can find no reference to them in syslog or anywhere else upon > > my subsequent reboot. > > > > I also had a couple of these messages pop up the other day while > > mounting/umounting USB thumb drives. I did not think anything of them at > > the time as the mounts/umounts completed successfully. > > > > Please advise. Thanks. > > > > -Tom > > I managed to snap a photo of my screen during shutdown. Here is the full text of the first of two lock order reversals I got last night during system shutdown, both of which are zfs-related to (it appears?) unmounts. A few lines got chopped as they were out-of-frame when I took the photo: shutting down local daemons: lock order reversal: 1st 0xfffff801194f67c8 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1237 2nd 0xfffff801194f6420 syncer (syncer) @ /usr/src/sys/kern/vfs_subr.c:22[..chopped...] KDB: stack backtrace: db_trace_self_wrapper() at db_trace_delf_wrapper+0x2b/frame 0xfffffe01ac78[...chopped...] kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe01ac784650 witness_checkorder() at witness_checkorder+0xd23/frame 0xfffffe01ac7846e0 __lockmgr_args() __lockmgr_args+0x878/frame 0xfffffe01ac784810 vop_stdlock() at vop_stdlock+0x3c/frame 0xfffffe01ac784830 VOP_LOCK1_APV() at VOP_LOCK1_APV+0xf5/frame 0xfffffe01ac784860 _vn_lock() at _vn_lock+0xab/frame 0xfffffe01ac7848d0 vputx() at vputx+0x240/frame 0xfffffe01ac784930 dounmount at dounmount+0x327/frame 0xfffffe01ac7849b0 sys_unmount() at sys_unmount+0x356/frame 0xfffffe01ac784ac0 amd64_syscall() at amd64_syscall+0x265/frame 0xfffffe01ac784bf0 Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe01ac784bf0 --- syscall (22, FreeBSD ELF64, sys_unmount, rip = 0x80191c72a, rsp[...chopped...] I have a zpool on an external USB HDD that I export at shutdown via rc.shutdown.local. Don't know if that is contributing to this or not. When I get a chance to bring down the system I will manually export it before shutdown to see if that makes any difference.