Re: [PATCH 0/2] clk: kunit: Fix the lockdep warnings

[Guenter Roeck]

On 8/9/23 16:21, Stephen Boyd wrote:
> +kunit-dev
>
> Quoting Maxime Ripard (2023-07-21 00:09:31)
> > Hi,
> >
> > Here's a small series to address the lockdep warning we have when
> > running the clk kunit tests with lockdep enabled.
> >
> > For the record, it can be tested with:
> >
> > $ ./tools/testing/kunit/kunit.py run \
> >      --kunitconfig=drivers/clk \
> >      --cross_compile aarch64-linux-gnu- --arch arm64 \
> >      --kconfig_add CONFIG_DEBUG_KERNEL=y \
> >      --kconfig_add CONFIG_PROVE_LOCKING=y
> >
> > Let me know what you think,
>
> Thanks for doing this. I want to roll these helpers into the clk_kunit.c
> file that I had created for some other clk tests[1]. That's mostly
> because clk.c is already super long and adding kunit code there makes
> that problem worse. I'll try to take that patch out of the rest of the
> series and then add this series on top and resend.
>
> I don't know what to do about the case where CONFIG_KUNIT=m though. We
> have to export clk_prepare_lock/unlock()? I really don't want to do that
> even if kunit is enabled (see EXPORT_SYMBOL_IF_KUNIT). Maybe if there
> was a GPL version of that, so proprietary modules can't get at kernel
> internals on kunit enabled kernels.

EXPORT_SYMBOL_IF_KUNIT defines a module namespace. You could go a step
further and define a CLK_KUNIT module namespace or similar. That would
of course still permit abuse, but it would have to be _very_ intentional.
There is an EXPORT_SYMBOL_NS_GPL(), so you could further restrict it
to GPL only.

Guenter