[15483] in athena10
Re: Debathena Fails to load AFS kernel modules
daemon@ATHENA.MIT.EDU (Benjamin Kaduk)
Tue Feb 27 21:16:22 2018
Date: Tue, 27 Feb 2018 20:15:55 -0600
From: Benjamin Kaduk <kaduk@mit.edu>
To: Anne Collin <acollin@mit.edu>
Cc: debathena@mit.edu
Message-ID: <20180228021555.GH50954@kduck.kaduk.org>
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In-Reply-To: <89813BAA-6781-433C-86A7-3613C0B50D5B@mit.edu>
[re-adding debathena@mit.edu to the cc list]
Hi Anne,
Thanks for the data. It looks like you're running the Ubuntu
"hardware enablement" kernel with the 14.04.5 release, as opposed to
the older linux kernel series that shipped with the original 14.04
release. With some help from another developer, we spotted a
potential issue with this setup, in that the kernel you're running
is compiled using a compiler feature called "retpoline", that was
introduced as a partial mitgiation for the "spectre" vulnerabilities
that have been in the news recently. This changes the contract for
interactions between kernel modules such as the one from OpenAFS,
and the main kernel, so that the kernel module in question would
need to use the same compiler as the main kernel. Unfortunately,
the updated compiler does not appear to be readily available on your
system, and so (if our hypothesis is right), the mismatch would
prevent openafs from working.
We could get one more data point to try to confirm if this is the
case, via:
sudo dmesg | grep openafs
In terms of possible workarounds, if you do not actually need the
"nardware enablement" kernel for the particular hardware in
question, you could try to downgrade to an older kernel; otherwise,
the simplest solution might be to upgrade the machine to a newer
Ubuntu release (e.g., 16.04 "Xenial", the source of the "hardware
enablement" kernel; the requisite compiler looks to be present on
Xenial systems).
This is all pretty complicated and confusing, so please ask for
clarification as needed.
-Ben
On Mon, Feb 26, 2018 at 04:07:46PM -0500, Anne Collin wrote:
> Sorry, the actual response to “lsb_release -a” is
>
> “No LSB modules are available.
> Distributor ID: Ubuntu
> Description: Ubuntu 14.04.5 LTS
> Release: 14.04
> Codename: trusty”
>
> Anne
>
> > On 26 Feb 2018, at 14:31, Anne Collin <acollin@mit.edu> wrote:
> >
> > Hi Ben,
> >
> > Thanks for the quick response, I'm attaching the screenshot of the terminal.
> >
> >
> > ________________________________________
> > De : Benjamin Kaduk [kaduk@mit.edu]
> > Envoyé : lundi 26 février 2018 13:53
> > À : Anne Collin
> > Cc : debathena
> > Objet : Re: Debathena Fails to load AFS kernel modules
> >
> > Hi Anne,
> >
> > On Mon, Feb 26, 2018 at 01:50:03PM -0500, Anne Collin wrote:
> >> Hi,
> >>
> >> For some reason I am not able to access AFS MIT user accounts (not just mine, several MIT students’) on our lab Debathena machine (used to work fine until last week). I logged with the local admin account, and tried to troubleshoot with these instructions http://kb.mit.edu/confluence/display/istcontrib/Troubleshooting+Debathena+installation <https://master.mailbutler.io/redirect/90F34E00-60F7-403B-BBCB-CAD61795EB13>, but when I try to restart openafs-client, I get the error
> >> “Starting AFS services:modprobe: ERROR: could not insert ‘opens’: Exec format error
> >>
> >> Failed to load AFS kernel module, not starting AFS”
> >>
> >> Do you have any advice on what I should do? I’m even ready to reinstall Debathena, but I didn’t find any documentation online on how to do that.
> >
> > The OpenAFS packages used by Debathena are maintained as part of
> > Debian and Ubuntu, so in general issues seen with them may also be
> > present on non-Debathena machines. To help us understand what's
> > going on, could you provide the output of the following commands?
> >
> > uname -a
> >
> > lsb_release -a
> >
> > dpkg-query -W openafs-client
> >
> > Thanks,
> >
> > Ben
> > <Screenshot from 2018-02-26 14:30:25.png>
>
