From owner-freebsd-current@FreeBSD.ORG Thu Aug 18 03:15:18 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1C8E31065673; Thu, 18 Aug 2011 03:15:18 +0000 (UTC) (envelope-from kaduk@mit.edu) Received: from dmz-mailsec-scanner-5.mit.edu (DMZ-MAILSEC-SCANNER-5.MIT.EDU [18.7.68.34]) by mx1.freebsd.org (Postfix) with ESMTP id B321B8FC0A; Thu, 18 Aug 2011 03:15:17 +0000 (UTC) X-AuditID: 12074422-b7ba7ae000000a14-99-4e4c803872bb Received: from mailhub-auth-2.mit.edu ( [18.7.62.36]) by dmz-mailsec-scanner-5.mit.edu (Symantec Messaging Gateway) with SMTP id 55.C9.02580.8308C4E4; Wed, 17 Aug 2011 23:00:08 -0400 (EDT) Received: from outgoing.mit.edu (OUTGOING-AUTH.MIT.EDU [18.7.22.103]) by mailhub-auth-2.mit.edu (8.13.8/8.9.2) with ESMTP id p7I30Fm8011862; Wed, 17 Aug 2011 23:00:15 -0400 Received: from multics.mit.edu (MULTICS.MIT.EDU [18.187.1.73]) (authenticated bits=56) (User authenticated as kaduk@ATHENA.MIT.EDU) by outgoing.mit.edu (8.13.6/8.12.4) with ESMTP id p7I30DVZ001892 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 17 Aug 2011 23:00:15 -0400 (EDT) Received: (from kaduk@localhost) by multics.mit.edu (8.12.9.20060308) id p7I30Cva009453; Wed, 17 Aug 2011 23:00:12 -0400 (EDT) Date: Wed, 17 Aug 2011 23:00:12 -0400 (EDT) From: Benjamin Kaduk To: John In-Reply-To: <20110816040519.GA49864@FreeBSD.org> Message-ID: References: <20110816040519.GA49864@FreeBSD.org> User-Agent: Alpine 1.10 (GSO 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrLIsWRmVeSWpSXmKPExsUixG6nomvR4ONncK5Ly2LOmw9MFsce/2Sz WL/yDasDs8eMT/NZAhijuGxSUnMyy1KL9O0SuDKW3f3DWHCDu6Jz3w+mBsZXnF2MnBwSAiYS rX3/mSBsMYkL99azdTFycQgJ7GOUeLPwIpSzgVFi4rmpLBDOASaJM92n2CGcBkaJ7surWEH6 WQS0Jf7dPA42i01ARWLmm41sILaIgJTE0zmXWUBsZgFziacfloHVCAPVL305H6yGU8BQ4uvd bcxdjBwcvAIOEk/PRIKEhQQMJI6vWAhWIiqgI7F6/xSwMbwCghInZz6BGmkp8W/tL9YJjIKz kKRmIUktYGRaxSibklulm5uYmVOcmqxbnJyYl5dapGuql5tZopeaUrqJERyqLko7GH8eVDrE KMDBqMTDa/jK20+INbGsuDL3EKMkB5OSKO/eWh8/Ib6k/JTKjMTijPii0pzU4kOMEhzMSiK8 bQpAOd6UxMqq1KJ8mJQ0B4uSOC/XTgc/IYH0xJLU7NTUgtQimKwMB4eSBG9zHVCjYFFqempF WmZOCUKaiYMTZDgP0HC2KpDhxQWJucWZ6RD5U4yKUuK8nvVACQGQREZpHlwvLJW8YhQHekWY dy5IFQ8wDcF1vwIazAQ0+NYuD5DBJYkIKakGxi6TxNkzqvIW/uN6FKPW8KbM4sd+q93+mdpd fxcZaoZb5tVdlr13t9PJYPvTLoUnnh+mXNvWbMSZ0R+er5ARKcuV1nz5J8u97TlntnNMbtsv oz7DsuhekPMfy2ld22/wBz69Pl3+w2WhQ0cv6DZ2GLvN0H+d78q04uBBrukPJWK7iux+y6l4 KLEUZyQaajEXFScCAL6rYnwAAwAA Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org Subject: Re: Three LOR with latest -current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 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: Thu, 18 Aug 2011 03:15:18 -0000 Hello John, These seem to be well-known, per http://ipv4.sources.zabbadoz.net/freebsd/lor.html On Tue, 16 Aug 2011, John wrote: > Hi folks, > > I'm seeing 3 lock order reversals with an up-to-date -current > system. Stock system, GENERIC kernel. Let me know if this isn't > enough information. Just booting the system and the dmesg. > > Thanks, > John > > > lock order reversal: > 1st 0xfffffe0289627db8 ufs (ufs) @ /usr/src.2011-08-14_10.53pm_EDT/sys/ufs/ffs/ffs_snapshot.c:425 > 2nd 0xffffff9f0db49778 bufwait (bufwait) @ /usr/src.2011-08-14_10.53pm_EDT/sys/kern/vfs_bio.c:2658 > 3rd 0xfffffe00404a8098 ufs (ufs) @ /usr/src.2011-08-14_10.53pm_EDT/sys/ufs/ffs/ffs_snapshot.c:546 This looks like #285. > > > lock order reversal: > 1st 0xffffff9f0db49778 bufwait (bufwait) @ /usr/src.2011-08-14_10.53pm_EDT/sys/kern/vfs_bio.c:2658 > 2nd 0xfffffe004034dcb0 snaplk (snaplk) @ /usr/src.2011-08-14_10.53pm_EDT/sys/ufs/ffs/ffs_snapshot.c:818 The line numbers are a bit off, but this could be #269. > > > lock order reversal: > 1st 0xfffffe004034dcb0 snaplk (snaplk) @ /usr/src.2011-08-14_10.53pm_EDT/sys/kern/vfs_vnops.c:301 > 2nd 0xfffffe0289627db8 ufs (ufs) @ /usr/src.2011-08-14_10.53pm_EDT/sys/ufs/ffs/ffs_snapshot.c:1620 And this would be #240. Since they are so commonly reported (but no deadlocks have been attributed to them), it seems likely that they are harmless. Perhaps we should tell WITNESS to not warn about them ... -Ben Kaduk