Re: [PATCH v2] x86/nmi: Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus()

[Waiman Long <llong@redhat.com>]

On 12/4/24 8:10 AM, Thomas Gleixner wrote:
> On Tue, Dec 03 2024 at 10:07, Waiman Long wrote:
>> +	/*
>> +	 * Call the emergency handler first, if set
>> +	 * Emergency handler is not traced or checked by nmi_check_duration().
>> +	 */
>> +	ehandler = READ_ONCE(desc->emerg_handler);
>> +	if (ehandler)
>> +		handled = ehandler(type, regs);
> Shouldn't this just stop processing right here?

Yes in the case of crash_nmi_callback(). I suppose it is a no-return 
call. As the emergency handler is supposed to be a general mechanism in 
design, I don't want to make too many assumptions of what will happen 
when the handler is invoked.

What suggested changes do you have in your mind? I do make a minor 
mistake in the functional comment that is reported by kernel test robot 
which I will fix in the next version.

Cheers,
Longman