Re: md-cluster Oops 4.9.13

[Guoqing Jiang <gqjiang@suse.com>]

On 04/10/2017 09:25 PM, Marc Smith wrote:
> Hi,
>
> Sorry for the delay... I was hoping to cherry-pick this and test
> against 4.9.x, but it didn't apply cleanly, although it looks trivial
> to do it by hand. Is it recommended/okay to test this patch against
> 4.9.x? Will the fix eventually be merged into 4.9.x?

I think you can have a try with the patch then see what will happen, the 
better
way is try with the latest code though people don't like always update 
kernel,
but it is not a material for stable 4.9.x from my understanding.

Thanks,
Guoqing

>
>
> --Marc
>
> On Tue, Apr 4, 2017 at 11:01 PM, Guoqing Jiang <jgq516@gmail.com> wrote:
>>
>> On 04/04/2017 10:06 PM, Marc Smith wrote:
>>> Hi,
>>>
>>> I encountered an oops this morning when stopping a MD array
>>> (md-cluster)... there were 4 md-cluster array started, and they were
>>> in the middle of a rebuild. I stopped the first one and then stopped
>>> the second one immediately after and got the oops, here is a
>>> transcript of what was on my terminal session:
>>>
>>> [root@brimstone-1b ~]# mdadm --stop /dev/md/array1
>>> mdadm: stopped /dev/md/array1
>>> [root@brimstone-1b ~]# mdadm --stop /dev/md/array2
>>>
>>> Message from syslogd@brimstone-1b at Tue Apr  4 09:54:40 2017 ...
>>> brimstone-1b kernel: [649162.174685] BUG: unable to handle kernel NULL
>>> pointer dereference at 0000000000000098
>>>
>>> Using Linux 4.9.13 and here is the output from the kernel messages:
>>>
>>> --snip--
>>> [649158.014731] dlm: 5b3b8f94-7875-b323-5bb8-29fa6866f4a8: leaving the
>>> lockspace group...
>>> [649158.015233] dlm: 5b3b8f94-7875-b323-5bb8-29fa6866f4a8: group event
>>> done 0 0
>>> [649158.015303] dlm: 5b3b8f94-7875-b323-5bb8-29fa6866f4a8:
>>> release_lockspace final free
>>> [649158.015331] md: unbind<nvme0n1p1>
>>> [649158.042540] md: export_rdev(nvme0n1p1)
>>> [649158.042546] md: unbind<nvme1n1p1>
>>> [649158.048501] md: export_rdev(nvme1n1p1)
>>> [649161.759022] md127: detected capacity change from 1000068874240 to 0
>>> [649161.759025] md: md127 stopped.
>>> [649162.174685] BUG: unable to handle kernel NULL pointer dereference
>>> at 0000000000000098
>>> [649162.174727] IP: [<ffffffff81868b40>] recv_daemon+0x1e9/0x373
>>
>> Looks like the recv_daemon is still running after stop array, commit
>> 48df498 "md: move bitmap_destroy to the beginning of __md_stop"
>> ensure it won't happen.
>>
>>
>> [snip]
>>
>>> Perhaps this is already fixed in later versions? Let me know if you
>>> need any additional information.
>>
>> Could you pls try with the latest version? Please let me know if you
>> still see it, thanks.
>>
>> Regards,
>> Guoqing
>>