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

Christophe Leroy [off-list ref] writes:

Le 20/09/2021 à 15:55, Nathan Lynch a écrit :

quoted

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.