Re: [uml-devel] Issues with a rather unusual configured NFS server

[Richard Weinberger <richard@nod.at>]

[-- Attachment #1: Type: text/plain, Size: 3402 bytes --]

Am 01.09.2013 18:09, schrieb Toralf Förster:
> On 08/30/2013 04:36 PM, Richard Weinberger wrote:
>> Am 30.08.2013 16:10, schrieb Toralf Förster:
>>> On 08/29/2013 03:30 PM, J. Bruce Fields wrote:
>>>> On Thu, Aug 29, 2013 at 11:57:45AM +0200, richard -rw- weinberger wrote:
>>>>> On Wed, Aug 28, 2013 at 7:21 PM, Toralf Förster <toralf.foerster@gmx.de> 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 Förster 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 fuzzy 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 via loop device
>>>>>>>>>>    - and the NFS server is forced to umount the NFS share
>>>>>>>>>>    - and the server forced to restart the NSF service afterwards
>>>>>>>>>>    - and trinity is used
>>>>>>>>>>
>>>>>>>>>> I could find a scenario for an automated bisect. 2 times it brought this commit
>>>>>>>>>> commit 68a3396178e6688ad7367202cdf0af8ed03c8727
>>>>>>>>>> Author: J. Bruce Fields <bfields@redhat.com>
>>>>>>>>>> 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 commit
>>>>>>>> nfs4_set_delegation() failures result in nfs4_put_delegation being
>>>>>>>> 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 top
>>>> of my head, but I may have forgotten others.
>>>>
>>>
>>> well, 7255e71 and 3c50ba8 I'd say.
>>>
>>>>> Or are these bugs just more likely to hit on UML?
>>>
>>> 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.
>>>
>>>
>>>> That's also possible.
>>>>
>>>>> This is not the first NFS issue found by Toralf using UML and Trinity.
>>>>
>>>> Yep.  The testing is definitely appreciated.
>>>
>>> Thx - in the mean while although my UML bisect scripts are working fine
>>> and trinity is stable enough even in UML environments to be trust worth.
>>
>> That's good to know.
>> Thanks you and trinity we got rid of some nasty UML bugs.
> 
> yeah, but there's (among others) one of them still in the wild:
> If I start an UML and resize the terminal (KDE Konsole) during the boot
> phase then it just crashes sometimes.

Does the attached patch fix the problem?

Thanks,
//richard


[-- Attachment #2: winch_irq.diff --]
[-- Type: text/x-patch, Size: 345 bytes --]

diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 36e12f0..e7d1983 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -337,6 +337,7 @@ static struct irq_chip normal_irq_type = {
 	.irq_disable = dummy,
 	.irq_enable = dummy,
 	.irq_ack = dummy,
+	.irq_mask = dummy,
 };
 
 static struct irq_chip SIGVTALRM_irq_type = {

[-- Attachment #3: Type: text/plain, Size: 433 bytes --]

------------------------------------------------------------------------------
Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more!
Discover the easy way to master current and previous Microsoft technologies
and advance your career. Get an incredible 1,500+ hours of step-by-step
tutorial videos with LearnDevNow. Subscribe today and save!
http://pubads.g.doubleclick.net/gampad/clk?id=58040911&iu=/4140/ostg.clktrk

[-- Attachment #4: Type: text/plain, Size: 194 bytes --]

_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel