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From:   Naresh Kamboju <naresh.kamboju@linaro.org>
Date:   Wed, 17 Jul 2019 14:26:49 +0530
Message-ID: <CA+G9fYt+UmakwaZAM4gR-B+V8kZUJVNh8gFBcXa4zU2j0Cz0ZQ@mail.gmail.com>
Subject: Re: [PATCH v10 6/9] kselftests: cgroup: add freezer controller self-tests
To:     Roman Gushchin <guro@fb.com>
Cc:     Roman Gushchin <guroan@gmail.com>, Tejun Heo <tj@kernel.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Kernel Team <Kernel-team@fb.com>,
        "cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        "lkft-triage@lists.linaro.org" <lkft-triage@lists.linaro.org>
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Hi Roman,

> The interaction between ptrace and freezer is complicated
> (as ptrace in general),so there are known cases when spurious
> cgroup transitions (frozen <-> non frozen <-> frozen ) can happen.

When test ran for 8 times it got failed 5 times.
I have noticed intermittent failure on x86_64, arm64 hikey device and
qemu_arm64.

>
> Does it create any difficulties? If so, I'll send a diff to ignore
> the result of this test for now.

No difficulties. I will mark this test case as known failure.

> > > This patch implements 9 tests for the freezer controller for
> > > cgroup v2:
> > ...
> > > 6) ptrace test: the test checks that it's possible to attach to
> > > a process in a frozen cgroup, get some information and detach, and
> > > the cgroup will remain frozen.
> >
> > selftests cgroup test_freezer failed because of the sys entry path not found.
>
> Can you, please, elaborate on this?

I see this failure output on screen and sharing log here.

Please find full test log here,
https://lkft.validation.linaro.org/scheduler/job/825346#L673

- Naresh