Re: Re: [PATCH] kernel/panic: Add "late_kdump" option for kdump in unstable condition

From: Masami Hiramatsu
Date: Sun Apr 20 2014 - 20:59:20 EST


(2014/04/18 12:09), Masami Hiramatsu wrote:
> (2014/04/17 22:43), Vivek Goyal wrote:
>> On Thu, Apr 17, 2014 at 10:59:14AM +0900, Masami Hiramatsu wrote:
>>
>> [..]
>>>>> @@ -112,9 +113,14 @@ void panic(const char *fmt, ...)
>>>>> /*
>>>>> * If we have crashed and we have a crash kernel loaded let it handle
>>>>> * everything else.
>>>>> - * Do we want to call this before we try to display a message?
>>>>> + * If we want to call this after we try to display a message, pass
>>>>> + * the "late_kdump" option to the kernel.
>>>>> */
>>>>> - crash_kexec(NULL);
>>>>> + if (!late_kdump)
>>>>> + crash_kexec(NULL);
>>>>> + else
>>>>> + pr_emerg("Warning: late_kdump option is set. Please DO NOT "
>>>>> + "report bugs about kdump failure with this option.\n");
>>>>
>>>> I think above message about DO NOT report bugs seems unnecessary.
>>>
>>> OK, so I just notify the option is set as below.
>>> "Warning: crash_kexec_post_notifiers is set.\n"
>>
>> I would say for the time being don't put any extra message. User will
>> think what this warning is supposed to mean. We can introduce one if
>> we run into many issues.
>
> Ah, I see.
>
>> For the time being we can just look at kernel logs and look at command
>> line options and see whether crash_kexec_post_notifiers was set or not.
>
> Yeah, I know. However since the kernel command line is shown in very early
> part of kernel logs, I worried about the case that it is pushed out from
> kmsg buffer. And usually users will send a bug report with the very last
> of the kernel logs because it becomes too long.

Anyway, I'll send v3 soon to remove that message completely :)

Thank you!

--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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