Re: [PATCH] perf test: perf stat tests fails on s390

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Code Fix: Replace with `if grep -q 'No supported events found' "${stat_output}"; then`. Standalone `grep -q` under `set -e` causes unexpected script abort.
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commit 4b80c04b99f0ab66b8227b70f1041582e256987c
Author: Thomas Richter <tmricht@linux.ibm.com>

perf test: perf stat tests fails on s390

This commit fixes a failure in the 'perf stat tests' on s390 z/VM by skipping
the test if the cycles and instructions events are unsupported. It checks the
output of the failed perf stat command for 'No supported events found' to
determine if the test should be skipped.

> diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> index 298ce454b45a1..41bac99300a16 100755
> --- a/tools/perf/tests/shell/stat.sh
> +++ b/tools/perf/tests/shell/stat.sh
> @@ -583,6 +583,11 @@ test_hide_zero_events_stat() {
>    # Check that --metric-only works with --hide-zero-events
>    if ! perf stat --hide-zero-events --metric-only -e instructions,cycles true > "${stat_output}" 2>&1
>    then
> +    grep -q 'No supported events found' "${stat_output}"
> +    if [ $? -eq 0 ]; then

[Severity: Medium]
In test_hide_zero_events_stat(), will this standalone grep cause the script
to abort unexpectedly?

If the script is running with 'set -e' and the perf stat command fails for
any reason other than unsupported events, grep will not find a match and will
return a non-zero exit code.

This non-zero exit directly forces a script abort, making the subsequent
'$?' condition and fallback error handlers unreachable.

Should this be combined into the if statement directly?

    if grep -q 'No supported events found' "${stat_output}"; then
        echo "Hide zero events stat test [Skipped - events not supported]"
        return
    fi

> +      echo "Hide zero events stat test [Skipped - events not supported]"
> +      return
> +    fi
>      echo "Hide zero events stat test [Failed - metric-only command failed]"
>      err=1
>      return

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Sashiko AI review · https://sashiko.dev/#/patchset/20260902115218.2977412-1-tmricht@linux.ibm.com?part=1