Re: [PATCH v1] perf stat: Avoid uninitialized memory read on error

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Tue, Sep 08, 2026 at 03:07:20PM -0700, Ian Rogers wrote:
> If has_supported_counters fails then msg was passed to ui__error
> regardless of whether an error was written into msg leading to reading
> uninitialized memory. Avoid this by always terminating msg at
> initialization.
> 
> Opportunistically reduce the scope of msg to make its use clearer.

Thanks, applied to perf-tools-next, for v7.4.

- Arnaldo
 
> Fixes: c9a8c343ef2f ("perf stat: When no events, don't report an error if there is none")
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/builtin-stat.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index c50cf230f16e..37752d6bfef4 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -777,7 +777,6 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  	int interval = stat_config.interval;
>  	int times = stat_config.times;
>  	int timeout = stat_config.timeout;
> -	char msg[BUFSIZ];
>  	unsigned long long t0, t1;
>  	struct evsel *counter;
>  	size_t l;
> @@ -908,6 +907,9 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  		}
>  	}
>  	if (!has_supported_counters && !stat_config.null_run) {
> +		char msg[BUFSIZ];
> +
> +		msg[0] = '\0';
>  		if (open_err) {
>  			evsel__open_strerror(evlist__first(evsel_list), &target, open_err,
>  					     msg, sizeof(msg));
> -- 
> 2.55.0.979.g7e5102b832-goog
>