From owner-freebsd-current@FreeBSD.ORG Fri Jul 31 15:55:26 2009 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 B49EE1065670; Fri, 31 Jul 2009 15:55:26 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 856128FC1B; Fri, 31 Jul 2009 15:55:26 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 039AE46B17; Fri, 31 Jul 2009 11:55:26 -0400 (EDT) Received: from jhbbsd.hudson-trading.com (unknown [209.249.190.8]) by bigwig.baldwin.cx (Postfix) with ESMTPA id 4141D8A0A2; Fri, 31 Jul 2009 11:55:25 -0400 (EDT) From: John Baldwin To: Attilio Rao Date: Fri, 31 Jul 2009 10:27:16 -0400 User-Agent: KMail/1.9.7 References: <152E0401-8750-4363-85D8-F058BD87C150@mac.com> <200907310853.52946.jhb@freebsd.org> <3bbf2fe10907310711v4ed3ba48jac84ea99d863d0a9@mail.gmail.com> In-Reply-To: <3bbf2fe10907310711v4ed3ba48jac84ea99d863d0a9@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200907311027.16492.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Fri, 31 Jul 2009 11:55:25 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,RDNS_NONE autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: freebsd-current@freebsd.org, pjd@freebsd.org Subject: Re: panic: mutex Giant owned at .../base/head/sys/kern/kern_exit.c:131 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: Fri, 31 Jul 2009 15:55:27 -0000 On Friday 31 July 2009 10:11:25 am Attilio Rao wrote: > 2009/7/31 John Baldwin : > > On Friday 31 July 2009 2:36:46 am Marcel Moolenaar wrote: > >> All, > >> > >> I got the following panic after I had to import my ZFS file system on > >> ia64. > >> The following panic happened when executing "zpool import": > >> > >> panic: mutex Giant owned at /nfs/freebsd/base/head/sys/kern/ > >> kern_exit.c:131 > >> cpuid = 0 > >> KDB: enter: panic > > > > It looks like ZFS doesn't actually ever check if any of the namei lookups it > > does internally return with Giant locked. For example, it doesn't check > > NDHASGIANT() in lookupnameat(). Fixing this may be a bit of work as I'm not > > sure it is safe to drop Giant right after the namei(). If it is because the > > end vnode's returned are always MPSAFE then that fix is easy. If not, then > > Giant needs to be held until the code stops frobbing the vnode returned from > > the lookup. > > NDHASGIANT() reflects the locking of the mountpoint where the vnode is > on so you need to size it in regard of what the namei() consumer is > going to expect in terms of locking with such vnode/mountpoint. True, but in this case the Giant lock that is leaked is locked in namei(). If you have LOCKPARENT set and you lookup your / then the parent vnode may be from a different !MPSAFE filesystem even if your filesystem is safe, yes? -- John Baldwin