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

Pnina Feder
2026-01-08T20:14:07Z

Hi Steve,

> On Thu, 8 Jan 2026 08:48:57 +0100
> Peter Zijlstra <peterz@infradead.org> 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

I have added your suggestion to the documentation on v5.

Thanks,
Pnina