Re: [PATCH v4 03/13] arm/kexec: refactor for kernel/Kconfig.kexec

On Wed, Jul 5, 2023, at 17:22, Eric DeVolder wrote:
> On 7/5/23 10:05, Arnd Bergmann wrote:
>> On Wed, Jul 5, 2023, at 16:19, Eric DeVolder wrote:
>> 
>> I see this is now in linux-next, and it caused a few randconfig
>> build issues, these never happened in the past:
>
> Arnd,
> Thanks for looking at this!
>
> I received randconfig errors from Andrew Morton's machinery. When 
> investigating I
> found that randconfig was able to specify CRASH_DUMP without KEXEC, and 
> that lead
> to problems. I believe this situation existed prior to this series as 
> well.

On Arm, there was definitely a bug because one could enable CRASH_DUMP
without enabling KEXEC, but that had no effect at all. I only noticed
the problem testing linux-next because it turned from silently broken
into a build failure

> Specifically CRASH_DUMP does not have a dependency on KEXEC, or select 
> (only s390
> has this hole closed).
>
> For CRASH_DUMP, this series now selects KEXEC to close this gap, which is what a
> sane config would have (ie both CRASH_DUMP and KEXEC).

Right, that is the easier way out here.

> Do you think the changes outlined below are still needed?

I think only the first one still applies on arm, you need to ensure
that ARCH_SUPPORTS_CRASH_DUMP has the same dependency as
ARCH_SUPPORTS_KEXEC, or it just depends on ARCH_SUPPORTS_KEXEC.

    Arnd