Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: Fedora 32 rpc.gssd misbehavior
To:     Chuck Lever <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@redhat.com>,
        Bruce Fields <bfields@fieldses.org>
Cc:     Simo Sorce <simo@redhat.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
References: <83856C49-309A-4AD6-9B27-9F93FDDE00DF@oracle.com>
 <48B9E144-41CA-4DF0-A88D-2F6652A0EBF1@oracle.com>
From:   Steve Dickson <SteveD@RedHat.com>
Message-ID: <fb14b95f-a0fd-5fae-29db-15ad8ab6066a@RedHat.com>
Date:   Thu, 30 Jul 2020 10:43:07 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.5.0
MIME-Version: 1.0
In-Reply-To: <48B9E144-41CA-4DF0-A88D-2F6652A0EBF1@oracle.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk


On 7/29/20 2:27 PM, Chuck Lever wrote:
> 
> 
>> On Jul 29, 2020, at 1:19 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
>>
>> Hi!
>>
>> I recently updated my test systems from EL7 to Fedora 32, and
>> NFSv4.0 with Kerberos has stopped working.
>>
>> I mount with "klimt.ib" as before. The client workload stops
>> dead when the server tries to perform its first CB_RECALL.
>>
>> I added some client instrumentation:
>>
>>   kernel: NFSv4: Callback principal (nfs@klimt.ib.1015granger.net) does not match acceptor (nfs@klimt.ib).
>>   kernel: NFS: NFSv4 callback contains invalid cred
>>
>> I boosted gssd verbosity, and it says:
>>
>>   rpc.gssd[986]: doing downcall: lifetime_rec=72226 acceptor=nfs@klimt.ib
>>
>> But it knows the full hostname for the server:
>>
>>   rpc.gssd[986]: Full hostname for 'klimt.ib' is 'klimt.ib.1015granger.net'
>>
>>
>> The acceptor appears to come from the Kerberos library. Shouldn't
>> it be canonicalized? If so, should the Kerberos library do it, or
>> should gssd? Since this behavior appeared after an upgrade, I
>> suspect a Kerberos library regression. But it could be config-
>> related, since both systems were re-imaged from the ground up.
>>
>> Also noticing some other problems on the server (missing hostname
>> strings in debug messages, sssd_kcm infinite loops, and gssd
>> sending garbage to the client after the NULL request that
>> establishes the callback context).
>>
>> But let's look at the client acceptor problem first.
> 
> I believe I found the problem.
> 
> 8bffe8c5ec1a ("gssd: add /etc/nfs.conf support") added a number of gssd config
> options to /etc/nfs.conf, including "avoid-dns". The default setting of avoid-
> dns is 1. When I set this option on my client system explicitly to 0, NFSv4.0
> with Kerberos works again.
Strange... What is failing in rpc.gssd when it is set to 1?
Maybe it has something to do with your DNS setup?

> 
> Is there a reason the default setting is 1?
Looking back... It's always bee set to 1. So no good reason ;-) 

steved.
> n
> 
> --
> Chuck Lever
> 
> 
>