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.

quoted

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This patch implements 9 tests for the freezer controller for
cgroup v2:

...

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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