Re: [PATCH v3 3/3] printk: use the lockless ringbuffer

[lijiang]

å 2020å07æ02æ 21:31, Petr Mladek åé:
> On Thu 2020-07-02 17:43:22, lijiang wrote:
>> å 2020å07æ02æ 17:02, John Ogness åé:
>>> On 2020-07-02, lijiang <lijiang@xxxxxxxxxx> wrote:
>>>> About the VMCOREINFO part, I made some tests based on the kernel patch
>>>> v3, the makedumpfile and crash-utility can work as expected with your
>>>> patch(userspace patch), but, unfortunately, the vmcore-dmesg(kexec-tools)
>>>> can't correctly read the printk ring buffer information, and get the
>>>> following error:
>>>>
>>>> "Missing the log_buf symbol"
>>>>
>>>> The kexec-tools(vmcore-dmesg) should also have a similar patch, just like
>>>> in the makedumpfile and crash-utility.
>>>
>>> Yes, a patch for this is needed (as well as for any other related
>>> software floating around the internet).
>>>
>>> I have no RFC patches for vmcore-dmesg. Looking at the code, I think it
>>> would be quite straight forward to port the makedumpfile patch. I will
>>
>> Yes, it should be a similar patch.
>>
>>> try to make some time for this.
>>>
>> That would be nice. Thank you, John Ogness.
>>
>>> I do not want to patch any other software for this. I think with 3
>>> examples (crash, makedumpfile, vmcore-dmesg), others should be able to
>>
>> It's good enough to have the patch for the makedumpfile, crash and vmcore-dmesg,
>> which can ensure the kdump(userspace) work well.
> 
> I agree that this three are the most important ones and should be
> enough.
> 
> Thanks a lot for working on it and testing it.
> 
My pleasure. I will test the vmcore-dmesg later.

Thanks.
Lianbo

> Best Regards,
> Petr
>