Re: [BUG] kernel panics with drbd

[Matthew Vernon <mcv21@cam.ac.uk>]

Hi,

On 05/08/15 09:48, Ian Campbell wrote:
> On Tue, 2015-08-04 at 22:24 +0100, Matthew Vernon wrote:
>> On 04/08/15 15:39, Matthew Vernon wrote:
>>> Hi,
>>>
>>> On 04/08/15 15:22, Ian Campbell wrote:
>>>> On Tue, 2015-08-04 at 14:52 +0100, Matthew Vernon wrote:
>>>>> Hi,
>>>>
>>>> Hello,
>>>>
>>>>> I'm getting dom0 kernel panics, relating to moderately heavy use of
>>>>> drbd. I think this is a Xen bug.
>>>>
>>>> It is remarkably similar looking to
>>>> http://blog.chinewalking.com/drbd-kernel-oops-w-trim/ . Do you have 
>>>> trim?
>>>
>>> I seem to, yes:
>>>
>>> Aug  4 14:28:24 ophon kernel: [2856757.049680] drbd mws-02474: Agreed 
>>> to
>>> support TRIM on protocol level
>>>
>>> I have DRBD 8.9.2~rc1-2.
>>
>> [FTAOD, I think this means that this cannot be a repeat of the issue 
>> mentioned in that blog post?]
> 
> I must confess I'm a bit confused about the versioning of drbd, while
> Jessie ships the 8.9.2~rc1-2 userspace it appears (from inspection of the
> kernel source) to contain version 8.4.3 of the kernel side.

Those should, AIUI, work together (they both claim '(api:1/proto:86-101)').

> I think it's the kernel side which the blog post is referring too, which
> would also be consistent with the kernel side crash.

Yes, stable does have module version 8.4.3.

> Alternatively I don't know if drbd upstream provides a convenient way to
> build and install the modules in an out of tree way?

I built the 8.4.6 kernel module, and that has resolved the kernel
panics. So this does seem to have been the "trim" issue you suggested,
and a problem with version-compatibility between drbd kernel & userland.

So, sorry for bothering you, and thanks for the help. I'll try and get
Debian to ship a newer drbd kernel module (and DRBD to be more honest
about which versions of kernel and userland play nicely together).

Regards,

Matthew