[PATCH] print kdump kernel loaded status in stack dump

[Petr Tesarik]

On Fri, 19 Jan 2018 08:16:04 -0800
Andi Kleen <ak at linux.intel.com> wrote:

> On Fri, Jan 19, 2018 at 02:45:38PM +0900, Sergey Senozhatsky wrote:
> > On (01/18/18 10:02), Andi Kleen wrote:  
> > > Dave Young <dyoung at redhat.com> writes:  
> > > >  		printk("%sHardware name: %s\n",
> > > >  		       log_lvl, dump_stack_arch_desc_str);
> > > > +	if (kexec_crash_loaded())
> > > > +		printk("%skdump kernel loaded\n", log_lvl);  
> > > 
> > > Oops/warnings are getting longer and longer, often scrolling away
> > > from the screen, and if the kernel crashes backscroll does not work
> > > anymore, so precious information is lost.  
> > 
> > true. I even ended up having a console_reflush_on_panic() function. it
> > simply re-prints with a delay [so I can at least read the oops] logbuf
> > entries every once in a while, staring with the first oops_in_progress
> > record.  
> 
> It would be better to make scrollback work even after panic (e.g. with a polled
> keyboard driver)

I ended up using a serial console on all my machines. Yes, even my
laptop has one (virtual, provided by Intel AMT).

Anyway, what do you mean by a polled keyboard driver? My keyboard is
connected with USB. A polling xhci driver? Surely possible, but is it
worth the effort?

Petr T