Re: [PATCH v4] panic: add panic_force_cpu= parameter to redirect panic to a specific CPU

[Steven Rostedt]

On Thu, 8 Jan 2026 08:48:57 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> > +	panic_force_cpu=
> > +			[KNL,SMP] Force panic handling to execute on a specific CPU.
> > +			Format: <cpu number>
> > +			Some platforms require panic handling to occur on a
> > +			specific CPU for the crash kernel to function correctly.
> > +			This can be due to firmware limitations, interrupt routing
> > +			constraints, or platform-specific requirements where only
> > +			a particular CPU can safely enter the crash kernel.
> > +			When set, panic() will redirect execution to the specified
> > +			CPU before proceeding with the normal panic and kexec flow.
> > +			If the target CPU is offline or unavailable, panic proceeds
> > +			on the current CPU.  
> 
> It this stays; it should have a warning that it makes the panic less reliable.

Agreed. It should probably end with:

              This option should only be used for systems with the above
              constraints as it will cause the panic operation to be less
              reliable.

-- Steve