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From:   Brendan Higgins <brendanhiggins@google.com>
Date:   Wed, 29 Sep 2021 13:46:49 -0700
Message-ID: <CAFd5g44_4+WJrjzSZfQmk+T1Sm-E7ARdWxNzsc+Upku_A-gLqA@mail.gmail.com>
Subject: Re: [PATCH v1 0/6] kunit: build kunit tests without structleak plugin
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Shuah Khan <shuah@kernel.org>, David Gow <davidgow@google.com>,
        Kees Cook <keescook@chromium.org>,
        Rafael Wysocki <rafael@kernel.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Ulf Hansson <ulf.hansson@linaro.org>, andreas.noever@gmail.com,
        michael.jamet@intel.com,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        yehezkelshb@gmail.com, Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        KUnit Development <kunit-dev@googlegroups.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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On Fri, Sep 17, 2021 at 12:38 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, Sep 17, 2021 at 8:10 AM Brendan Higgins
> <brendanhiggins@google.com> wrote:
> >
> > The structleak plugin causes the stack frame size to grow immensely when
> > used with KUnit; this is caused because KUnit allocates lots of
> > moderately sized structs on the stack as part of its assertion macro
> > implementation. For most tests with small to moderately sized tests
> > cases there are never enough KUnit assertions to be an issue at all;
> > even when a single test cases has many KUnit assertions, the compiler
> > should never put all these struct allocations on the stack at the same
> > time since the scope of the structs is so limited; however, the
> > structleak plugin does not seem to respect the compiler doing the right
> > thing and will still warn of excessive stack size in some cases.
> >
> > These patches are not a permanent solution since new tests can be added
> > with huge test cases, but this serves as a stop gap to stop structleak
> > from being used on KUnit tests which will currently result in excessive
> > stack size.
> >
> > Of the following patches, I think the thunderbolt patch may be
> > unnecessary since Linus already fixed that test. Additionally, I was not
> > able to reproduce the error on the sdhci-of-aspeed test. Nevertheless, I
> > included these tests cases for completeness. Please see my discussion
> > with Arnd for more context[1].
> >
> > NOTE: Arnd did the legwork for most of these patches, but did not
> > actually share code for some of them, so I left his Signed-off-by off of
> > those patches as I don't want to misrepresent him. Arnd, please sign off
> > on those patches at your soonest convenience.
>
> Thanks a lot for picking up this work where I dropped the ball.
>
> Patches 1-5 look good to me, and I replied on one remaining issue I see
> with patch 6. I think you did more work on these that I did, by doing
> a nice write-up and splitting them into separate patches with useful
> changelogs, you should keep authorship, and just change my
> S-o-b to Suggested-by.
>
> If you prefer to keep me as the author, then the correct way would
> be to commit them with --author= to ensure that the author and
> first s-o-b match.

Sounds good. I will keep the one that has you as the author since I
just rebased it, but I will move you to Suggested-by on the others.

Thanks!