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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 15 Dec 2021 11:10:42 +0100
Message-ID: <CAMuHMdWQZA_fS-pr+4wVYtZ6h9Bx4PJ_92qpDNZ2kdjpzj+DHQ@mail.gmail.com>
Subject: Re: [PATCH -next] lib: TEST_REF_TRACKER should depend on REF_TRACKER
 instead of selecting it
To:     Eric Dumazet <edumazet@google.com>
Cc:     Jakub Kicinski <kuba@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        netdev <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Eric,

On Wed, Dec 15, 2021 at 10:51 AM Eric Dumazet <edumazet@google.com> wrote:
> On Wed, Dec 15, 2021 at 1:36 AM Geert Uytterhoeven
> <geert+renesas@glider.be> wrote:
> > TEST_REF_TRACKER selects REF_TRACKER, thus enabling an optional feature
> > the user may not want to have enabled.  Fix this by making the test
> > depend on REF_TRACKER instead.
>
> I do not understand this.

The issue is that merely enabling tests should not enable optional
features, to prevent unwanted features sneaking into a product.
If tests depend on features, all tests for features that are enabled can
still be enabled (e.g. made modular, so they can be loaded when needed).

> How can I test this infra alone, without any ref_tracker being selected ?
>
> I have in my configs
>
> CONFIG_TEST_REF_TRACKER=m
> # CONFIG_NET_DEV_REFCNT_TRACKER is not set
> # CONFIG_NET_NS_REFCNT_TRACKER is not set
>
> This should work.

So you want to test the reference tracker, without having any actual
users of the reference tracker enabled?

Perhaps REF_TRACKER should become visible, cfr. CRC32 and
the related CRC32_SELFTEST?

> I would not have sent patches built around ref_tracker if I had no
> ways of testing the base infrastructure.

> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -2114,8 +2114,7 @@ config BACKTRACE_SELF_TEST
> >
> >  config TEST_REF_TRACKER
> >         tristate "Self test for reference tracker"
> > -       depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
> > -       select REF_TRACKER
> > +       depends on DEBUG_KERNEL && STACKTRACE_SUPPORT && REF_TRACKER
> >         help
> >           This option provides a kernel module performing tests
> >           using reference tracker infrastructure.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds