Re: [RFC PATCH 3/6] selftests/damon/_damon_sysfs: implement DamonProbes

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The error result of `write_file()` for setting the probe weight is silently discarded.
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--- Patch [3]: [RFC PATCH 3/6] selftests/damon/_damon_sysfs: implement DamonProbes ---
commit 12ef2c079bfc3ec5e9f25fc085e18c6bca931488
Author: SJ Park <[email protected]>

selftests/damon/_damon_sysfs: implement DamonProbes

Extend _damon_sysfs.py to support staging and committing DAMON probes.
It will be used for setting DAMON probes via sysfs changes for testing
purposes.

> diff --git a/tools/testing/selftests/damon/_damon_sysfs.py b/tools/testing/selftests/damon/_damon_sysfs.py
> --- a/tools/testing/selftests/damon/_damon_sysfs.py
> +++ b/tools/testing/selftests/damon/_damon_sysfs.py

[ ... ]

> +class DamonProbe:
> +    weight = None
> +    filters = None
> +    probes = None
> +    idx = None
> +
> +    def __init__(self, weight=0, filters=None):
> +        self.weight = weight
> +        if filters is None:
> +            filters = DamonFilters()
> +        self.filters = filters
> +        self.filters.probe = self
> +
> +    def sysfs_dir(self):
> +        return os.path.join(self.probes.sysfs_dir(), '%d' % self.idx)
> +
> +    def stage(self):
> +        err = write_file(
> +                os.path.join(self.sysfs_dir(), 'weight'), '%d' % self.weight)
> +        return self.filters.stage()

[Severity: Medium]
Is err intentionally ignored here? If write_file() fails to write the weight
to sysfs, it returns an error string. Returning self.filters.stage() directly
without checking err will swallow the error and might cause tests to proceed
with incorrect assumptions about the probe configuration.

Should this check err before returning, similar to how it is handled in other
stage() methods?

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=3