Re: [patch] add kdump_after_notifier

[Vivek Goyal <vgoyal@in.ibm.com>]

On Thu, Jul 26, 2007 at 04:07:02PM +0200, Bernhard Walle wrote:
> * Takenori Nagano <t-nagano@ah.jp.nec.com> [2007-07-19 14:15]:
> > 
> > In latest kernel, we can't use panic_notifier_list if kdump is enabled.
> > panic_notifier_list is very useful function for debug, failover, etc...
> > 
> > So this patch adds a control file /proc/sys/kernel/dump_after_notifier
> > and resolves a problem users can not use both kdump and panic_notifier_list
> > at the same time.
> > 
> > kdump_after_notifier = 0
> >  -> panic()
> >     -> crash_kexec(NULL)
> > 
> > kdump_after_notifier = 1
> >  -> panic()
> >     -> atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
> >     -> crash_kexec(NULL)
> 
> What's problematic about this patch? I also would like to see that
> feature.

I would like to see the code which will get executed after panic and 
before crash_kexec(). This potentially makes crash dump feature unreliable
in the sense one can now register on panic_notifier_list and try to
do whole lot of things and might get stuck there. After the system
has crashed, one is not supposed to do a whole lot.

Thanks
Vivek