[PATCH 2/3] powerpc/cpuhp: BUG -> WARN conversion in offline path

[Nathan Lynch]

Christophe Leroy <christophe.leroy at csgroup.eu> writes:

> Le 20/09/2021 à 15:55, Nathan Lynch a écrit :
>> If, due to bugs elsewhere, we get into unregister_cpu_online() with a CPU
>> that isn't marked hotpluggable, we can emit a warning and return an
>> appropriate error instead of crashing.
>
> Is it only a bug situation, or is it something that can happen in real 
> life ?
>
> If it can happen in real life, kernels with panic_on_warn will still be 
> impacted.

I only found this by inspection, and it can happen only due to a bug in
CPU device registration at boot. The flag must not be set if the
platform or CPU can't support going offline.