Re: [PATCH v2 11/18] perf test cs-etm: Remove duplicate branch tests

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Undocumented global root check inappropriately skips the entire test suite for non-root users.
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commit e286213d8a9568ef4b5ffeadc05f64626a70b603
Author: James Clark <james.clark@linaro.org>

perf test cs-etm: Remove duplicate branch tests

This commit removes duplicate branch tests in perf script and perf report
modes for the Coresight ETM tests to improve test execution speed. It also
removes the perf report test from system-wide mode due to its large runtime
impact.

> diff --git a/tools/perf/tests/shell/test_arm_coresight.sh b/tools/perf/tests/shell/test_arm_coresight.sh
> index bbf89e944e7b1..8ed2c934c87d0 100755
> --- a/tools/perf/tests/shell/test_arm_coresight.sh
> +++ b/tools/perf/tests/shell/test_arm_coresight.sh
> @@ -20,6 +20,12 @@ skip_if_no_cs_etm_event() {
>  
>  skip_if_no_cs_etm_event || exit 2
>  
> +if [ "$(id -u)" != 0 ]; then
> +	# Requires root for -C and system wide tests
> +	echo "[Skip] No root permission"
> +	exit 2
> +fi
> +

[Severity: Medium]
The commit message states the patch's purpose is to remove duplicate branch
tests for a speedup, but this adds a new top-level check that skips the
entire test suite for non-root users. Is this intentional?

Relying strictly on UID=0 ignores modern capability-based access such as
CAP_PERFMON or CAP_SYS_ADMIN, as well as permissive sysctls like
kernel.perf_event_paranoid=-1.

Could this also unnecessarily bypass per-thread trace tests later in the
script that do not require system-wide privileges?

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260602-james-cs-context-tracking-fix-v2-0-85b5ce6f55c6@linaro.org?part=11