[patch] add kdump_after_notifier

[Takenori Nagano]

Hi Vivek,

Vivek Goyal wrote:
> On Thu, Jul 26, 2007 at 05:47:18PM +0200, Bernhard Walle wrote:
>> * Vivek Goyal <vgoyal at in.ibm.com> [2007-07-26 17:44]:
>>>> Of course, but that's why the patch doesn't change this by default but
>>>> gives the user the choice.
>>>>
>>> What value will distro set it to by default?
>> 0.
>>
>>> Can we be more specific in terms of functionality and code that exactly
>>> what we are trying to do after panic?
>> Well, KDB, but now everybody answers with “not mainline -- doesn't
>> count”.
>>
> 
> That's true. Its not mainline. We had similar discussion in the past
> also. I think we should allow only audited code to be run after panic().
> Leaving it open to modules or unaudited code makes this solution
> something like LKCD where whole lot of code used to run after the crash,
> hence was unreliable.

It is *not* KDB specific problem. Please grep in mainline kernel. You can find
some function using panic_notifier_list. (IPMI, softdog, heartbeat, etc...)
My patch gives a chance to use kdump for panic_notifier user. It is good for
kdump too, because kdump user goes to increase. :-)

Bernhard's idea (kdump uses panic_notifier) is very good for me. But it isn't
good for kdump user, because they want to take a dump ASAP when panicked.

Vivek, please think about this problem again.

If there is a developer who has the opinion on this problem, please give us your
opinion.

Thanks.

> If KDB goes mainline, then I think it is not a bad idea to call debugger
> first (if it is enabled) and then one can trigger crash dump from inside
> the debugger.
> Thanks
> Vivek
> 
>