Re: [PATCH] profile: setup_profiling_timer() is moslty not implemented

[Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>]

On Thu, 21 Jul 2022 20:55:09 +0100 Ben Dooks <ben-linux@xxxxxxxxx> wrote:

> The setup_profiling_timer() is mostly un-implemented by many
> architectures. In many places it isn't guarded by CONFIG_PROFILE
> which is needed for it to be used. Make it a weak symbol in
> kernel/profile.c and remove the 'return -EINVAL' implementations
> from the kenrel.
> 
> There are a couple of architectures which do return 0 from
> the setup_profiling_timer() function but they don't seem to
> do anything else with it. To keep the /proc compatibility for
> now, leave these for a future update or removal.
> 
> On ARM, this fixes the following sparse warning:
> arch/arm/kernel/smp.c:793:5: warning: symbol 'setup_profiling_timer' was not declared. Should it be static?

I'll grab this.

We have had some problems with weak functions lately.  See

https://lore.kernel.org/all/87ee0q7b92.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#u

Hopefully that was a rare corner case.