From owner-freebsd-hackers@freebsd.org Thu Jul 7 00:12:29 2016 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E4B63B758D1; Thu, 7 Jul 2016 00:12:29 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 857D5126D; Thu, 7 Jul 2016 00:12:29 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id u670CLT1011655 (version=TLSv1 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Thu, 7 Jul 2016 03:12:21 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua u670CLT1011655 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id u670CIZE011654; Thu, 7 Jul 2016 03:12:18 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 7 Jul 2016 03:12:18 +0300 From: Konstantin Belousov To: David Cross Cc: freebsd-stable@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: Reproducable panic in FFS with softupdates and no journaling (10.3-RELEASE-pLATEST) Message-ID: <20160707001218.GI38613@kib.kiev.ua> References: <20160706151822.GC38613@kib.kiev.ua> <20160706173758.GF38613@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.1 (2016-04-27) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Jul 2016 00:12:30 -0000 On Wed, Jul 06, 2016 at 02:21:20PM -0400, David Cross wrote: > (kgdb) up 5 > #5 0xffffffff804aafa1 in brelse (bp=0xfffffe00f77457d0) at buf.h:428 > 428 (*bioops.io_deallocate)(bp); > Current language: auto; currently minimal > (kgdb) p/x *(struct buf *)0xfffffe00f77457d0 > $1 = {b_bufobj = 0xfffff80002e88480, b_bcount = 0x4000, b_caller1 = 0x0, > b_data = 0xfffffe00f857b000, b_error = 0x0, b_iocmd = 0x0, b_ioflags = > 0x0, > b_iooffset = 0x0, b_resid = 0x0, b_iodone = 0x0, b_blkno = 0x115d6400, > b_offset = 0x0, b_bobufs = {tqe_next = 0x0, tqe_prev = > 0xfffff80002e884d0}, > b_vflags = 0x0, b_freelist = {tqe_next = 0xfffffe00f7745a28, > tqe_prev = 0xffffffff80c2afc0}, b_qindex = 0x0, b_flags = 0x20402800, > b_xflags = 0x2, b_lock = {lock_object = {lo_name = 0xffffffff8075030b, > lo_flags = 0x6730000, lo_data = 0x0, lo_witness = > 0xfffffe0000602f00}, > lk_lock = 0xfffff800022e8000, lk_exslpfail = 0x0, lk_timo = 0x0, > lk_pri = 0x60}, b_bufsize = 0x4000, b_runningbufspace = 0x0, > b_kvabase = 0xfffffe00f857b000, b_kvaalloc = 0x0, b_kvasize = 0x4000, > b_lblkno = 0x0, b_vp = 0xfffff80002e883b0, b_dirtyoff = 0x0, > b_dirtyend = 0x0, b_rcred = 0x0, b_wcred = 0x0, b_saveaddr = 0x0, b_pager > = { > pg_reqpage = 0x0}, b_cluster = {cluster_head = {tqh_first = 0x0, > tqh_last = 0x0}, cluster_entry = {tqe_next = 0x0, tqe_prev = 0x0}}, > b_pages = {0xfffff800b99b30b0, 0xfffff800b99b3118, 0xfffff800b99b3180, > 0xfffff800b99b31e8, 0x0 }, b_npages = 0x4, b_dep = { > lh_first = 0xfffff800023d8c00}, b_fsprivate1 = 0x0, b_fsprivate2 = 0x0, > b_fsprivate3 = 0x0, b_pin_count = 0x0} > > > This is the freshly allocated buf that causes the panic; is this what is > needed? I "know" which vnode will cause the panic on vnlru cleanup, but I > don't know how to walk the memory list without a 'hook'.. as in, i can > setup the kernel in a state that I know will panic when the vnode is > cleaned up, I can force a panic 'early' (kill -9 1), and then I could get > that vnode.. if I could get the vnode list to walk. Was the state printed after the panic occured ? What is strange is that buffer was not even tried for i/o, AFAIS. Apart from empty b_error/b_iocmd, the b_lblkno is zero, which means that the buffer was never allocated on the disk. The b_blkno looks strangely high. Can you print *(bp->b_vp) ? If it is UFS vnode, do p *(struct inode)(->v_data). I am esp. interested in the vnode size. Can you reproduce the problem on HEAD ?