Re: [patch] add kdump_after_notifier

Bernhard Walle
2007-07-26T15:34:50Z

* Vivek Goyal <vgoyal@in.ibm.com> [2007-07-26 17:32]:
> 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.

Of course, but that's why the patch doesn't change this by default but
gives the user the choice.

Thanks,
Bernhard