Re: [PATCH net-next] net: mctp: Stop selecting flow support for KUnit tests

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 25 Sep 2026 21:25:10 +0200 Karl Mehltretter wrote:
> MCTP_TEST selects MCTP_FLOWS, which also enables SKB_EXTENSIONS when no
> transport requires them. Remove the selection to follow the dependency
> rule in Documentation/dev-tools/kunit/style.rst.
> 
> The two flow-specific tests already skip when MCTP_FLOWS is disabled.
> The remaining tests can run in either configuration.

This patch causes the CI's "kunit-all/alltests" job to fail at the build
configuration step, before any KUnit test actually runs:

  ERROR:root:Not all Kconfig options selected in kunitconfig were in the
  generated .config. This is probably due to unsatisfied dependencies.
  Missing: CONFIG_MCTP_FLOWS=y

tools/testing/kunit/configs/all_tests.config (used by this job) lists
CONFIG_MCTP_FLOWS=y explicitly. However, MCTP_FLOWS in
net/mctp/Kconfig has no user-visible prompt:

  config MCTP_FLOWS
          bool
          depends on MCTP
          select SKB_EXTENSIONS

so it can only be turned on by another symbol's "select". Previously
MCTP_TEST selected it, which is what let all_tests.config's explicit
"CONFIG_MCTP_FLOWS=y" line take effect. After this patch removes that
select, nothing enables MCTP_FLOWS anymore, so olddefconfig silently
drops it and the kunit tooling treats the mismatch as fatal, aborting
the whole "alltests" run.

Since MCTP_FLOWS is a prompt-less symbol, simply listing it in a
kunitconfig fragment isn't enough on its own - it still needs to be
selected by something. Could you either:

 - keep a select of MCTP_FLOWS from an appropriate config (e.g. from
   MCTP_TEST guarded to only the flow-specific tests, if that's
   expressible), or
 - update tools/testing/kunit/configs/all_tests.config to select the
   flow tests explicitly (e.g. via a symbol that can select
   MCTP_FLOWS), or
 - give MCTP_FLOWS a real prompt so it can be enabled directly from a
   config fragment.

Let me know if you'd like the exact CI log for the failure.