From owner-freebsd-current@FreeBSD.ORG Tue Oct 11 16:07:16 2005 Return-Path: X-Original-To: current@FreeBSD.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 973E416A42F; Tue, 11 Oct 2005 16:07:16 +0000 (GMT) (envelope-from brdavis@odin.ac.hmc.edu) Received: from odin.ac.hmc.edu (Odin.AC.HMC.Edu [134.173.32.75]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1C8A743D48; Tue, 11 Oct 2005 16:07:16 +0000 (GMT) (envelope-from brdavis@odin.ac.hmc.edu) Received: from odin.ac.hmc.edu (localhost.localdomain [127.0.0.1]) by odin.ac.hmc.edu (8.13.0/8.13.0) with ESMTP id j9BG7FiN002926; Tue, 11 Oct 2005 09:07:15 -0700 Received: (from brdavis@localhost) by odin.ac.hmc.edu (8.13.0/8.13.0/Submit) id j9BG7FgR002925; Tue, 11 Oct 2005 09:07:15 -0700 Date: Tue, 11 Oct 2005 09:07:15 -0700 From: Brooks Davis To: Pawel Jakub Dawidek Message-ID: <20051011160715.GA2264@odin.ac.hmc.edu> References: <20051005024903.GA72743@heff.fud.org.nz> <20051005203639.GA20552@garage.freebsd.pl> <20051005205515.GA30350@odin.ac.hmc.edu> <20051011064014.GA76710@garage.freebsd.pl> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7JfCtLOvnd9MIVvH" Content-Disposition: inline In-Reply-To: <20051011064014.GA76710@garage.freebsd.pl> User-Agent: Mutt/1.4.1i X-Virus-Scanned: by amavisd-new X-Spam-Status: No, hits=0.0 required=8.0 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on odin.ac.hmc.edu Cc: Brooks Davis , FreeBSD Current , Andrew Thompson Subject: Re: panic: ifc_free_unit: bit is already cleared 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: Tue, 11 Oct 2005 16:07:16 -0000 --7JfCtLOvnd9MIVvH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 11, 2005 at 08:41:16AM +0200, Pawel Jakub Dawidek wrote: > On Wed, Oct 05, 2005 at 01:55:15PM -0700, Brooks Davis wrote: > +> On Wed, Oct 05, 2005 at 10:36:39PM +0200, Pawel Jakub Dawidek wrote: > +> > On Wed, Oct 05, 2005 at 03:49:03PM +1300, Andrew Thompson wrote: > +> > +> Hi, > +> > +>=20 > +> > +> I have found a repeatable panic with network device cloning, unfo= rtunatly I am > +> > +> unable to dump on this box. This is sparc64 with a 2 day old curr= ent. > +> >=20 > +> > The order is wrong in vlan_modevent(). > +> >=20 > +> > if_clone_detach() is freeing ifc_units field, so ifc_free_unit() sho= uld not > +> > be called after that. > +> >=20 > +> > This patch should fix the problem: > +> >=20 > +> > http://people.freebsd.org/~pjd/patches/if_vlan.c.patch > +>=20 > +> Yes. This does introduce a race in that a new interface could > +> be created between the vlan_clone_destroy loop and the call to > +> if_clone_detach. It's going to be hard to trigger, but it probably > +> should be fixed. Since cloning isn't performance critical, I think > +> adding a dead flag to the clone structure and failing all attempts once > +> the flag is set. >=20 > I think it is a low-risk patch and the race isn't really critical. > What do you guys think about going with this fix for 6.0? > I'm all for better fix (the one thompsa@ is working on) going to HEAD > and 6.1, but better fix - higher risk. > So what's your opinion? >=20 > Or maybe we will be able to create low-risk complete fix? The race is mostly a non-issue so I'd be OK with the low-risk fix. To hit the race you'd have to be trying (or forget that you are running some sort of interface management daemon). -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --7JfCtLOvnd9MIVvH Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFDS+MyXY6L6fI4GtQRAvY4AKCSq9kBz4+X42rna8XNSUvg/oXokACghTDP yqIVOFyo0fCnytwAu9/FaZ8= =NFiy -----END PGP SIGNATURE----- --7JfCtLOvnd9MIVvH--