From: "J. Bruce Fields" Subject: Re: [uml-devel] Issues with a rather unusual configured NFS server Date: Thu, 29 Aug 2013 09:30:10 -0400 Message-ID: <20130829133010.GA14773@fieldses.org> References: <52075E01.7030506@gmx.de> <20130812143640.GF4596@quack.suse.cz> <20130813215313.GH17781@fieldses.org> <20130827180655.GE14809@fieldses.org> <521E318C.7040401@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Toralf =?utf-8?Q?F=C3=B6rster?= , Linux NFS mailing list , "J. Bruce Fields" , "user-mode-linux-devel@lists.sourceforge.net" , Linux Kernel , Jan Kara , linux-ext4@vger.kernel.org To: richard -rw- weinberger Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Aug 29, 2013 at 11:57:45AM +0200, richard -rw- weinberger wrote= : > On Wed, Aug 28, 2013 at 7:21 PM, Toralf F=C3=B6rster wrote: > > On 08/27/2013 08:06 PM, J. Bruce Fields wrote: > >> On Tue, Aug 13, 2013 at 05:53:14PM -0400, bfields wrote: > >>> On Mon, Aug 12, 2013 at 04:36:40PM +0200, Jan Kara wrote: > >>>> On Sun 11-08-13 11:48:49, Toralf F=C3=B6rster wrote: > >>>>> so that the server either crashes (if it is a user mode linux i= mage) or at least its reboot functionality got broken > >>>>> - if the NFS server is hammered with scary NFS calls using a fu= zzy tool running at a remote NFS client under a non-privileged user id. > >>>>> > >>>>> It can re reproduced, if > >>>>> - the NFS share is an EXT3 or EXT4 directory > >>>>> - and it is created at file located at tempfs and mounted vi= a loop device > >>>>> - and the NFS server is forced to umount the NFS share > >>>>> - and the server forced to restart the NSF service afterward= s > >>>>> - and trinity is used > >>>>> > >>>>> I could find a scenario for an automated bisect. 2 times it bro= ught this commit > >>>>> commit 68a3396178e6688ad7367202cdf0af8ed03c8727 > >>>>> Author: J. Bruce Fields > >>>>> Date: Thu Mar 21 11:21:50 2013 -0400 > >>>>> > >>>>> nfsd4: shut down more of delegation earlier > >>> > >>> Thanks for the report. I think I see the problem--after this com= mit > >>> nfs4_set_delegation() failures result in nfs4_put_delegation bein= g > >>> called, but nfs4_put_delegation doesn't free the nfs4_file that h= as > >>> already been set by alloc_init_deleg(). > >>> > >>> Let me think about how to fix that.... > >> > >> Sorry for the slow response--can you check whether this fixes the > >> problem? > >> > > Yes. > > > > With the attached patch the problem can't be reproduced any longer = with > > the prepared test case and current git kernels. >=20 > BTW: Is nobody else fuzz testing NFS? I don't know. Toralf's reports are the only ones I recall off the top of my head, but I may have forgotten others. > Or are these bugs just more likely to hit on UML? That's also possible. > This is not the first NFS issue found by Toralf using UML and Trinity= =2E Yep. The testing is definitely appreciated. --b.