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From:   David Gow <davidgow@google.com>
Date:   Fri, 24 Apr 2020 14:36:48 +0800
Message-ID: <CABVgOS=k2eCMwt-Tz46=mCXg1Kxjb54sD1kW-R=mchFQiCgYTQ@mail.gmail.com>
Subject: Re: [PATCH v6 0/5] KUnit-KASAN Integration
To:     Alan Maguire <alan.maguire@oracle.com>
Cc:     Patricia Alfonso <trishalfonso@google.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        KUnit Development <kunit-dev@googlegroups.com>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>
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On Sat, Apr 18, 2020 at 11:28 PM Alan Maguire <alan.maguire@oracle.com> wrote:
>
>
> On Fri, 17 Apr 2020, David Gow wrote:
>
> > This patchset contains everything needed to integrate KASAN and KUnit.
> >
> > KUnit will be able to:
> > (1) Fail tests when an unexpected KASAN error occurs
> > (2) Pass tests when an expected KASAN error occurs
> >
> > Convert KASAN tests to KUnit with the exception of copy_user_test
> > because KUnit is unable to test those.
> >
>
> I tried building and running and things look good but I am
> still seeing the three failures I reported before, even with
> CONFIG_AMD_MEM_ENCRYPT not set.  My config is attached if you
> want to try and reproduce at your end.  Oddly this config was
> working before IIRC (once CONFIG_AMD_MEM_ENCRYPT was not set).
>
> Here's the failures:
>
>    # kasan_memchr: EXPECTATION FAILED at lib/test_kasan.c:545
>     Expected fail_data.report_expected == fail_data.report_found, but
>         fail_data.report_expected == 1
>         fail_data.report_found == 0
>     not ok 31 - kasan_memchr
>     # kasan_memcmp: EXPECTATION FAILED at lib/test_kasan.c:566
>     Expected fail_data.report_expected == fail_data.report_found, but
>         fail_data.report_expected == 1
>         fail_data.report_found == 0
>     not ok 32 - kasan_memcmp

I was able to reproduce these (along with a kasan_strings) failure,
and the cause seems to be some combination of __builtin functions
being inlined by the compiler and potentially dead code elimination,
as fixed by Daniel Axtens here:
https://lkml.org/lkml/2020/4/23/708

I've sent out v7 of the patchset[1], which I've rebased on top of
Daniel's patches, and can no longer reproduce those test failures with
your .config.

Cheers,
-- David

[1]: https://lkml.org/lkml/2020/4/24/80