Re: bcache: for-next unable to handle kernel NULL pointer dereference at 0000000000000019

Coly Li
2017-10-23T13:05:29Z

On 2017/10/23 下午8:59, Stefan Priebe - Profihost AG wrote:
> Hi Coly,
>
>
> Am 23.10.2017 um 14:56 schrieb Coly Li:
>> On 2017/10/23 下午7:42, Stefan Priebe - Profihost AG wrote:
>>> Hello,
>>>
>>> i picked all bcache patches from for-next to my 4.4 kernel to test the
>>> new controller.
>>>
>>> After doing so i see random kernel panics with the following trace:
>>
>> Hi Stefan,
>>
>> Thanks for the report. This is the 3rd report I see recently for NULL
>> pointer dereference, maybe they are related (or maybe not). Is it a
>> panic when bcache starts to run, or during heavy workload ?
>
> It's during heavy / normal workload.
>
>> If I may have chance to trigger similar oops on my server, that will be
>> much easier. So far I cannot reproduce any oops, neither by rebooting
>> and assemble bcache device by udev rules, nor compose bcache device and
>> run it by bash scripts...
>
> Do you need the line where this happens? It should be possible to get
> the line from the IP: [<ffffffffc04ef62e>] output?
>
This is very helpful. Is it possible to get a kdump crash for the kernel
oops, that will be much more informative :-)

Thanks.

--
Coly Li