[CentOS-devel] CBS kernel-debuginfo packages

[Wayne Betts]

On 6/7/2016 6:31 PM, Johnny Hughes wrote:
> On 06/07/2016 03:18 PM, Wayne Betts wrote:
>> On 6/7/2016 11:22 AM, Johnny Hughes wrote:
>>> On 06/07/2016 09:56 AM, Wayne Betts wrote:
>>>> I'm not sure if this is an appropriate place for this question - please gently
>>>> steer me to a better place if you think there is one.
>>>>
>>>> I have a machine using a kernel package from the CentOS Community Build System
>>>> (specifically kernel-3.18.21-16.el6 from
>>>> http://cbs.centos.org/koji/buildinfo?buildID=4757, but my question applies to
>>>> other CBS kernel versions as well from what I can tell)
>>>>
>>>> The machine is crashing with some regularity on Sunday mornings.  Looking at a
>>>> kdump core dump might help narrow down the cause of the crashes.
>>>>
>>>> But the CBS kernel packages don't appear to include kernel-debuginfo packages,
>>>> and the kernel.spec file appears to me (a non-expert for sure) to have had the
>>>> necessary pieces removed, so I don't know how to rebuild from the srpm and get
>>>> the debuginfo packages that way either.
>>>>
>>>> If someone could help me find or build the kernel-debuginfo package, it will be
>>>> appreciated.
>>>>
>>>
>>> Those kernel packages do not build debuginfo files.  That is also not
>>> nearly the newest package.  There is a 3.18.34-20 package here:
>>>
>>> http://cbs.centos.org/koji/buildinfo?buildID=11179
>>>
>>> You can see the packages that are built and look at all the build logs
>>> and root logs, etc, by going to:
>>>
>>> http://cbs.centos.org/koji/
>>>
>>> and adding kernel in the search box .. then picking the version you are
>>> interested in.
>>>
>>> But, as you can see in the above link, there are no debuginfo files
>>> produced.
>>>
>>> However, we do take updates directly from the kernel.org 3.18 LTS kernel
>>> tree, so there are a lot of things that have been fixed (and a lot of
>>> security updates) since 3.18.21 .. in fact you can see all of the
>>> changelogs starting with :
>>>
>>> https://cdn.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.18.22
>>>
>>> and using 23, 24. 25, 26, 27, 28, 29, 30, 31, 32, 33, and 34 for the
>>> last number to review all the changelogs.
>>>
>>> Thanks,
>>> Johnny Hughes
>>>
>>
>>
>> Thank you for your reply Johnny.  I tried the latest,
>> kernel-3.18.34-20.el6.x86_64, and that backfired - attempting to read from our
>> ceph cluster triggers an immediate crash.
>>
>> The behaviour of crashing on cephFS access starts at 3.18.30-20 in the CBS kernels.
>>
>> Meanwhile, 3.18.25-20 crashes early at boot, failing to mount the root
>> filesystem (so I don't know if the Ceph crash happens at this kernel version).
>>
>> I'm leaving the system live now at 3.18.25-19.  Assuming this hasn't introduced
>> some additional problem(s), it will be a while before we know if this has
>> reduced or eliminated the crashes we are experiencing.
> 
> Also, are you using this with XEN as well or just using this because it
> is a newer kernel?
> 

We are not using this with Xen.  The Ceph project recommendation is to upgrade
Ceph clients from the "stock" 2.6.32 Scientific Linux/RHEL 6 kernels (see the
notes at http://docs.ceph.com/docs/master/start/os-recommendations/ ).  We used
some 3.10 LTS series kernels for a bit, but our Ceph expert subsequently
suggested the use of the CBS 3.18 series kernel for our CephFS clients, though I
don't know if there was a specific reason other than 18 > 10.  (I'd guess he
found some anecdotal evidence or a recommendation online from a fellow CephFS
user to use the CBS 3.18 kernels instead of the LTS 3.10 kernels for Ceph, but
don't really know.)

-Wayne