Re: [PATCH v1 9/9] perf pmu: Fix race with concurrent tracepoint creation and removal in perf list

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] perf: missing explicit <stdlib.h> inclusion for realloc()
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commit 156bff4d99dfcb5bfd8c7cc38a4671357c5113e3
Author: Ian Rogers <irogers@google.com>

perf pmu: Fix race with concurrent tracepoint creation and removal in perf list

This commit modifies the perf tool to handle concurrent addition and removal of
tracepoint events by dynamically reallocating the aliases array and handling
-ENOENT gracefully.

> diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
> index e0a4cb2428ca4..137abad37c33b 100644
> --- a/tools/perf/util/pmus.c
> +++ b/tools/perf/util/pmus.c
[ ... ]
> @@ -597,8 +597,18 @@ static int perf_pmus__print_pmu_events__callback(void *vstate,
>  	struct sevent *s;
>  
>  	if (state->index >= state->aliases_len) {
> -		pr_err("Unexpected event %s/%s/\n", info->pmu->name, info->name);
> -		return 1;
> +		size_t new_len = max_t(size_t, 16, state->aliases_len * 2);
> +		struct sevent *new_aliases;
> +
> +		new_aliases = realloc(state->aliases, new_len * sizeof(struct sevent));

[Severity: Low]
Does this code in perf_pmus__print_pmu_events__callback() rely on implicit
header inclusions for realloc()?

Since the perf tool can be built against musl libc, which strictly separates
declarations and does not implicitly include <stdlib.h> through other
headers, should <stdlib.h> be explicitly included at the top of
tools/perf/util/pmus.c to prevent compilation failures?

> +		if (!new_aliases) {
> +			pr_err("Unexpected event %s/%s/\n", info->pmu->name, info->name);
> +			return 1;
> +		}
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260929021913.56010-1-irogers@google.com?part=9