Re: [PATCH v1 09/13] perf python: Validate CPU and thread maps in pyrf_evsel__open

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The explicit `Py_TYPE()` checks added to `pyrf_evsel__open` break Python subclassing for `perf.thread_map` and `perf.cpu_map` objects.
--

commit 909b91c5a1d04af18afad351b78395740e856d0b
Author: Ian Rogers <irogers@google.com>

perf python: Validate CPU and thread maps in pyrf_evsel__open

This commit adds explicit Py_TYPE checks to ensure the cpu and thread map
arguments passed to pyrf_evsel__open are of the correct types.

> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index f9398bc30a80b..62f404c40d8dc 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
[ ... ]
> @@ -2096,11 +2096,21 @@ static PyObject *pyrf_evsel__open(struct pyrf_evsel *pevsel,
>  					 &pcpus, &pthreads, &group, &inherit))
>  		return NULL;
>  
> -	if (pthreads != NULL && pthreads != Py_None)
> +	if (pthreads != NULL && pthreads != Py_None) {
> +		if (Py_TYPE(pthreads) != &pyrf_thread_map__type) {

[Severity: Medium]
Will this strict equality check break valid Python subclasses of thread_map?

Because pyrf_thread_map__type sets Py_TPFLAGS_BASETYPE, Python scripts are
permitted to subclass it, but Py_TYPE() will point to the subclass type and
fail this exact-type check.

Should this use PyObject_TypeCheck() instead to safely support subclassing?

> +			PyErr_SetString(PyExc_TypeError, "threads must be a thread_map");
> +			return NULL;
> +		}
>  		threads = ((struct pyrf_thread_map *)pthreads)->threads;
> +	}
>  
> -	if (pcpus != NULL && pcpus != Py_None)
> +	if (pcpus != NULL && pcpus != Py_None) {
> +		if (Py_TYPE(pcpus) != &pyrf_cpu_map__type) {

[Severity: Medium]
Similarly, does this strict equality block valid Python subclasses of cpu_map?

> +			PyErr_SetString(PyExc_TypeError, "cpus must be a cpu_map");
> +			return NULL;
> +		}
>  		cpus = ((struct pyrf_cpu_map *)pcpus)->cpus;
> +	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260623053515.2677888-1-irogers@google.com?part=9