Re: [PATCH v7 1/2] perf tests: Add test for uncore event sorting

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Unreachable else block in event_cb().
--

commit 73f78d43a9da9383b1db8bb57a775b964c9f8810
Author: Ian Rogers <irogers@google.com>

perf tests: Add test for uncore event sorting

Add a test for uncore event sorting matching multiple PMUs. Uncore PMUs
may have a common prefix, and parsing an event group for those PMUs
should result in correctly sorted evsels.

> diff --git a/tools/perf/tests/uncore-event-sorting.c b/tools/perf/tests/uncore-event-sorting.c
> new file mode 100644
> index 0000000000000..594fe7ff7bf6a
> --- /dev/null
> +++ b/tools/perf/tests/uncore-event-sorting.c

[ ... ]

> +static int event_cb(void *state, struct pmu_event_info *info)
> +{
> +	struct match_state *m = state;
> +	char *clean_name;
> +
> +	if (m->event1 && m->event2)
> +		return 1;
> +
> +	clean_name = clean_event_name(info);
> +	if (!clean_name)
> +		return 0;
> +
> +	if (!m->event1) {
> +		m->event1 = clean_name;
> +	} else if (!m->event2) {
> +		if (strcmp(m->event1, clean_name)) {
> +			m->event2 = clean_name;
> +			return 1;
> +		}
> +		free(clean_name);
> +	} else {
> +		free(clean_name);
> +	}

Is this else block unreachable?

Since there is an early return at the start of the function when both
m->event1 and m->event2 are non-NULL, we can only reach this point if at
least one of them is NULL.

If the first branch (!m->event1) is not taken, m->event1 is non-NULL.
If the second branch (!m->event2) is not taken, m->event2 is non-NULL.

This implies both are non-NULL, which would have triggered the early return
at the top of the function, leaving this block as dead code.

> +	return 0;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260518043140.2522141-1-irogers@google.com?part=1