From: Richard Weinberger Subject: Re: [uml-devel] Issues with a rather unusual configured NFS server Date: Fri, 30 Aug 2013 16:36:23 +0200 Message-ID: <5220ADE7.1010502@nod.at> References: <52075E01.7030506@gmx.de> <20130812143640.GF4596@quack.suse.cz> <20130813215313.GH17781@fieldses.org> <20130827180655.GE14809@fieldses.org> <521E318C.7040401@gmx.de> <20130829133010.GA14773@fieldses.org> <5220A7E2.1070704@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "J. Bruce Fields" , Linux NFS mailing list , "J. Bruce Fields" , "user-mode-linux-devel@lists.sourceforge.net" , Linux Kernel , Jan Kara , linux-ext4@vger.kernel.org To: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= Return-path: In-Reply-To: <5220A7E2.1070704@gmx.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Am 30.08.2013 16:10, schrieb Toralf F=C3=B6rster: > On 08/29/2013 03:30 PM, J. Bruce Fields wrote: >> On Thu, Aug 29, 2013 at 11:57:45AM +0200, richard -rw- weinberger wr= ote: >>> 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 = image) or at least its reboot functionality got broken >>>>>>>> - if the NFS server is hammered with scary NFS calls using a f= uzzy tool running at a remote NFS client under a non-privileged user id= =2E >>>>>>>> >>>>>>>> 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 v= ia loop device >>>>>>>> - and the NFS server is forced to umount the NFS share >>>>>>>> - and the server forced to restart the NSF service afterwar= ds >>>>>>>> - and trinity is used >>>>>>>> >>>>>>>> I could find a scenario for an automated bisect. 2 times it br= ought 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 co= mmit >>>>>> nfs4_set_delegation() failures result in nfs4_put_delegation bei= ng >>>>>> called, but nfs4_put_delegation doesn't free the nfs4_file that = has >>>>>> 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. >>> >>> BTW: Is nobody else fuzz testing NFS? >> >> I don't know. Toralf's reports are the only ones I recall off the t= op >> of my head, but I may have forgotten others. >> >=20 > well, 7255e71 and 3c50ba8 I'd say. >=20 >>> Or are these bugs just more likely to hit on UML? >=20 > This definitely not. I observed at a real system EXT4 corruptions/ > issues but reported them to the EXT4 mailing list. > It just took me a longer time to figure out a reliable configuration > with 2 UML machiens to automatic bisect it. >=20 >=20 >> That's also possible. >> >>> This is not the first NFS issue found by Toralf using UML and Trini= ty. >> >> Yep. The testing is definitely appreciated. >=20 > Thx - in the mean while although my UML bisect scripts are working fi= ne > and trinity is stable enough even in UML environments to be trust wor= th. That's good to know. Thanks you and trinity we got rid of some nasty UML bugs. Thanks, //richard