Re: + panic-avoid-the-extra-noise-dmesg.patch added to -mm tree

Sergey Senozhatsky
2018-12-05T08:00:44Z

On (12/05/18 14:29), Sergey Senozhatsky wrote:
> On (12/05/18 11:57), Sergey Senozhatsky wrote:
> > On (12/05/18 10:47), Feng Tang wrote:
>
> OK... So, apparently, what's happening is panic() calls smp_send_stop().
> And smp_send_stop()->native_stop_other_cpus() on x86 disables local APIC.
> So no fun anymore.
>
> If I keep APIC enabled on panic CPU, then I have my keyboard working,
> including PageUp-PageDown scrolling, sysrq handling, and so on.

Meeh, it's much harder than this. Worked on one machine only.

> PeterZ,
> for those folks who sometimes have to use framebuffer for debugging
> (just a trivial "let me scrollback and see the panic backtrace") and
> not always have access to serial console, can we have local APIC
> enabled on the panic_cpu? Or is it a terrible thing to ask for?

The question remains: can we have input irqs on panic_cpu after panic?

-ss