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From:   Marco Elver <elver@google.com>
Date:   Tue, 31 Aug 2021 12:46:00 +0200
Message-ID: <CANpmjNPp3dAcr+WfYxM6_uQOmFmDf60aL-LbXF12NCzP6P3-6Q@mail.gmail.com>
Subject: Re: [GIT PULL] s390 updates for 5.15 merge window
To:     Heiko Carstens <hca@linux.ibm.com>
Cc:     Christian Borntraeger <borntraeger@de.ibm.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Vasily Gorbik <gor@linux.ibm.com>, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        qemu-s390x <qemu-s390x@nongnu.org>
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On Tue, 31 Aug 2021 at 12:13, Heiko Carstens <hca@linux.ibm.com> wrote:
[...]
> I really don't think this is QEMU related. The test fails are sort of
> expected: we've seen KCSAN reports when the kernel boots and wanted to
> fix them later.
> However I have to admit that I wasn't aware of the KCSAN KUNIT tests,
> and wouldn't have sent the s390 KCSAN enablement upstream if I would
> have been aware of failing self tests.
>
> We'll fix them, and I let you know if things are supposed to work.
>
> Thanks a lot for making aware of this!

Note: Set `CONFIG_KCSAN_REPORT_ONCE_IN_MS=100` (or smaller) instead of
the default to make the test complete faster.

The pattern I see from what Nathan reported is that all test cases
that expect race reports don't observe them ("not ok" cases), and all
those where no races are meant to be reported are fine ("ok" cases).
Without actually seeing the log, I'm guessing that no races are
reported at all, which is certainly not working as intended.