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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Wed, 8 Sep 2021 19:05:09 +0200
Message-ID: <CAK8P3a1vNx1s-tcjtu6VDxak4NHyztF0XZGe3wOrNbigx1f4tw@mail.gmail.com>
Subject: Re: ipv4/tcp.c:4234:1: error: the frame size of 1152 bytes is larger
 than 1024 bytes [-Werror=frame-larger-than=]
To:     Shuah Khan <skhan@linuxfoundation.org>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Brendan Higgins <brendanhiggins@google.com>,
        Ariel Elior <aelior@marvell.com>,
        GR-everest-linux-l2@marvell.com, Wei Liu <wei.liu@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>, lkft-triage@lists.linaro.org,
        Arnd Bergmann <arnd@arndb.de>,
        "David S. Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Eric Dumazet <edumazet@google.com>
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On Wed, Sep 8, 2021 at 4:12 PM Shuah Khan <skhan@linuxfoundation.org> wrote:
> On 9/7/21 5:14 PM, Linus Torvalds wrote:
> > The KUNIT macros create all these individually reasonably small
> > initialized structures on stack, and when you have more than a small
> > handful of them the KUNIT infrastructure just makes the stack space
> > explode. Sometimes the compiler will be able to re-use the stack
> > slots, but it seems to be an iffy proposition to depend on it - it
> > seems to be a combination of luck and various config options.
> >
>
> I have been concerned about these macros creeping in for a while.
> I will take a closer look and work with Brendan to come with a plan
> to address it.

I've previously sent patches to turn off the structleak plugin for
any kunit test file to work around this, but only a few of those patches
got merged and new files have been added since. It would
definitely help to come up with a proper fix, but my structleak-disable
hack should be sufficient as a quick fix.

       Arnd