From owner-freebsd-current@freebsd.org Mon Feb 26 06:42:19 2018 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 252D4F2EF15 for ; Mon, 26 Feb 2018 06:42:19 +0000 (UTC) (envelope-from agapon@gmail.com) Received: from mail-lf0-f44.google.com (mail-lf0-f44.google.com [209.85.215.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 91F8485E03 for ; Mon, 26 Feb 2018 06:42:18 +0000 (UTC) (envelope-from agapon@gmail.com) Received: by mail-lf0-f44.google.com with SMTP id f75so15546203lfg.6 for ; Sun, 25 Feb 2018 22:42:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=iBMl6yFRmby7Y9SNFKdc18/hc1DkEW5PKKkryEvP3qg=; b=BDjc65WaADqBaa+iGJgSaVUiHucYLYyz34RQB7AxfN6KycUTXYhcQPfEswFhMwzvOT B/wM9un1UW29nU4qEQbO9JmfhnouKH0RNjxlkv7b1bqBFwZLp5dn40I1NsSeFU1Mt74P +iIgwj7+Dx1Xul+9apS8EgylOluzTdW9zLXDY0XZbBwh0+0Lfqz8aP5qDPST/+nTwaOr 3IkPpdacnqjve4Yf+k5hR4xqF0GEVo1x86gdbFQhEUSIKuI7t5BsvltWnARNnqQVYAdp /S9gyiPoPdEW+SKtRKYg7LAFihBexQJRB+fke4zCPGh88axmztI9TZQaLH5lir/ZiUTx nIww== X-Gm-Message-State: APf1xPCf4Lfpe+p4LHnkAjTuSsf4895PrmnxlKbISugw5ISR/4gSDcNy LFMuzefqdC+zWcxSzBPY5ifpOEhd X-Google-Smtp-Source: AG47ELtUfXb4HmyVwI4bscv6QPj97J2caTe9vPcM8uM69GXqCa4IBpflZJTbQFs6Ap0a+AaDTJcy1g== X-Received: by 10.25.150.78 with SMTP id y75mr6999798lfd.81.1519627336609; Sun, 25 Feb 2018 22:42:16 -0800 (PST) Received: from [192.168.0.88] (east.meadow.volia.net. [93.72.151.96]) by smtp.googlemail.com with ESMTPSA id a189sm1820083lfb.32.2018.02.25.22.42.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 25 Feb 2018 22:42:15 -0800 (PST) Subject: Re: lock order reversal To: Jon Brawn , FreeBSD current References: From: Andriy Gapon Message-ID: <244ca590-bd28-154c-84f3-4cda50ccd8e6@FreeBSD.org> Date: Mon, 26 Feb 2018 08:42:14 +0200 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.25 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: Mon, 26 Feb 2018 06:42:19 -0000 On 26/02/2018 07:18, Jon Brawn wrote: > Wotcha! > > So, I’ve been using FreeBSD 12-CURRENT at various svn releases for a while now, and I get quite a few “lock order reversal” dumps. The one I’ve got on my screen at the moment is for ufs / bufwait / ufs: > > root@brax:/usr/src/stand # lock order reversal: > 1st 0xfffffd0003ec17e8 ufs (ufs) @ /usr/src/sys/kern/vfs_subr.c:2602 > 2nd 0xffff0000410efa20 bufwait (bufwait) @ /usr/src/sys/ufs/ffs/ffs_vnops.c:282 > 3rd 0xfffffd00b83ca7e8 ufs (ufs) @ /usr/src/sys/kern/vfs_subr.c:2602 > stack backtrace: > #0 0xffff0000003b59d4 at witness_debugger+0x64 > #1 0xffff00000032bd34 at __lockmgr_args+0x6ac > #2 0xffff0000005c6af0 at ffs_lock+0x88 > #3 0xffff000000679eb0 at VOP_LOCK1_APV+0xac > #4 0xffff000000426fa8 at _vn_lock+0x64 > #5 0xffff000000417550 at vget+0x78 > #6 0xffff000000409fdc at vfs_hash_get+0xec > #7 0xffff0000005c2b94 at ffs_vgetf+0x44 > #8 0xffff0000005b96a8 at softdep_sync_buf+0x9f4 > #9 0xffff0000005c7834 at ffs_syncvnode+0x26c > #10 0xffff0000005a1b5c at ffs_truncate+0x6b0 > #11 0xffff0000005ce3cc at ufs_direnter+0x778 > #12 0xffff0000005d64bc at ufs_makeinode+0x4b8 > #13 0xffff0000005d2b90 at ufs_create+0x38 > #14 0xffff000000677168 at VOP_CREATE_APV+0xac > #15 0xffff00000042691c at vn_open_cred+0x264 > #16 0xffff00000041fc84 at kern_openat+0x208 > #17 0xffff00000064b59c at do_el0_sync+0x8bc > > Is there something I should be doing to help debug these? IMO, no. Please ignore LORs involving "bufwait", "filedesc structure", "syncer" unless you experience any real problem (like a lock up). -- Andriy Gapon