Date:   Fri, 3 Mar 2023 10:47:33 +0100 (GMT+01:00)
From:   Matthieu Baerts <matthieu.baerts@tessares.net>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Naresh Kamboju <naresh.kamboju@linaro.org>,
        Paolo Abeni <pabeni@redhat.com>, stable@vger.kernel.org,
        patches@lists.linux.dev, linux-kernel@vger.kernel.org,
        torvalds@linux-foundation.org, akpm@linux-foundation.org,
        linux@roeck-us.net, shuah@kernel.org, patches@kernelci.org,
        lkft-triage@lists.linaro.org, pavel@denx.de, jonathanh@nvidia.com,
        f.fainelli@gmail.com, sudipm.mukherjee@gmail.com,
        srw@sladewatkins.net, rwarsow@gmx.de, mptcp@lists.linux.dev,
        Florian Westphal <fw@strlen.de>,
        Mat Martineau <mathew.j.martineau@linux.intel.com>,
        Anders Roxell <anders.roxell@linaro.org>
Message-ID: <3d92e773-896c-43c3-94ae-cb7851213c55@tessares.net>
In-Reply-To: <ZAG8dla274kYfxoK@kroah.com>
References: <20230301180657.003689969@linuxfoundation.org> <CA+G9fYtDGpgT4dckXD-y-N92nqUxuvue_7AtDdBcHrbOMsDZLg@mail.gmail.com> <ZAB6pP3MNy152f+7@kroah.com> <CA+G9fYsHbQyQFp+vMnmFKDSQxrmj-VKsexWq-aayxgrY+0O7KQ@mail.gmail.com> <CA+G9fYsn+AhWTFA+ZJmfFsM71WGLPOFemZp_vhFMMLUcgcAXKg@mail.gmail.com> <9586d0f99e27483b600d8eb3b5c6635b50905d82.camel@redhat.com> <CA+G9fYuLQEfeTjx52NxbXV5914YJQ2tVd8k4SJjrAryujPjnqA@mail.gmail.com> <ZAG8dla274kYfxoK@kroah.com>
Subject: Re: [PATCH 6.1 00/42] 6.1.15-rc1 review
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Hi Greg, Naresh, Paolo,

Thank you for the new version and for having reported the issue and running=
 MPTCP selftests!

3 Mar 2023 10:23:06 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:

> On Fri, Mar 03, 2023 at 02:34:05PM +0530, Naresh Kamboju wrote:
>> On Fri, 3 Mar 2023 at 13:34, Paolo Abeni <pabeni@redhat.com> wrote:
>>>
>>> Hello,
>>>
>>> On Fri, 2023-03-03 at 01:32 +0530, Naresh Kamboju wrote:
>>>> On Thu, 2 Mar 2023 at 16:30, Naresh Kamboju <naresh.kamboju@linaro.org=
> wrote:
>>>>>
>>>>> On Thu, 2 Mar 2023 at 16:00, Greg Kroah-Hartman
>>>>> <gregkh@linuxfoundation.org> wrote:
>>>>>> =E2=80=A6
>>>>>
>>>>> ....
>>>>>
>>>>>> =E2=80=A6
>>>>>
>>>>> Me either.
>>>>> That is the reason I have shared "Assertion" above.
>>>>>
>>>>>> =E2=80=A6
>>>>>
>>>>> We are running our bisection scripts.
>>>>
>>>> We have tested with 6.1.14 kselftests source again and it passes.
>>>> Now that we have upgraded to 6.2.1 kselftests source, we find that
>>>> there is this problem reported. so, not a kernel regression.
>>>
>>> I read the above as you are running self-tests from 6.2.1 on top of an
>>> older (6.1) kernel. Is that correct?
>>
>> correct.
>>
>>> If so failures are expected;
>
> Shouldn't the test be able to know that "new features" are not present
> and properly skip the test for when that happens?=C2=A0 Otherwise this fe=
els
> like a problem going forward as no one will know if this feature can be
> used or not (assuming it is a new feature and not just a functional
> change.)

All MPTCP selftests are designed to run on the same kernel version they are=
 attached to. This allows us to do more checks knowing they are not suppose=
d to fail on newer kernel versions and not being skipped if there is an err=
or when trying to use the new feature. If there are fixes, we make sure the=
 stable team is Cc'ed. If there are API changes, it would be visible becaus=
e we would need to adapt existing selftests.

That's how we thought we should design MPTCP selftests. Maybe we need to ch=
ange this design?

Is it a common practice to run selftests' latest version on older kernels?

Cheers,
Matt
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