On Tue, Jul 14, 2015 at 03:34:30PM +0000, dwalker@fifo99.com wrote:

On Tue, Jul 14, 2015 at 11:02:08AM -0400, Vivek Goyal wrote:

quoted

On Tue, Jul 14, 2015 at 01:59:19PM +0000, dwalker@fifo99.com wrote:

quoted

On Mon, Jul 13, 2015 at 08:19:45PM -0500, Eric W. Biederman wrote:

quoted

dwalker@fifo99.com writes:

quoted

On Fri, Jul 10, 2015 at 08:41:28AM -0500, Eric W. Biederman wrote:

quoted

Hidehiro Kawai [off-list ref] writes:

quoted

You can call panic notifiers and kmsg dumpers before kdump by
specifying "crash_kexec_post_notifiers" as a boot parameter.
However, it doesn't make sense if kdump is not available.  In that
case, disable "crash_kexec_post_notifiers" boot parameter so that
you can't change the value of the parameter.

Nacked-by: "Eric W. Biederman" [off-list ref]

I think it would make sense if he just replaced "kdump" with "kexec".

It would be less insane, however it still makes no sense as without
kexec on panic support crash_kexec is a noop.  So the value of the
seeting makes no difference.

Can you explain more, I don't really understand what you mean. Are you suggesting
the whole "crash_kexec_post_notifiers" feature has no value ?

Daniel,

BTW, why are you using crash_kexec_post_notifiers commandline? Why not
without it?

It was explained in the prior thread but to rehash, the notifiers are used to do a switch
over from the crashed machine to another redundant machine.

So why not detect failure using polling or issue notifications from second
kernel.

IOW, expecting that a crashed machine will be able to deliver notification
reliably is falwed to begin with, IMHO.

If a machine is failing, there are high chance it can't deliver you the
notification. Detecting that failure suing some kind of polling mechanism
might be more reliable. And it will make even kdump mechanism more
reliable so that it does not have to run panic notifiers after the crash.

Thanks
Vivek