Re: [PATCH 1/4] perf timechart: Release event samples at the end

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

On Fri, Jun 05, 2026 at 04:11:52PM -0700, Namhyung Kim wrote:
> Add timechart__release() to free all data structures added during the
> sample processing.
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/builtin-timechart.c | 54 ++++++++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
> index 04dbb944a42720b4..7c4ace51302e260c 100644
> --- a/tools/perf/builtin-timechart.c
> +++ b/tools/perf/builtin-timechart.c
> @@ -1548,6 +1548,59 @@ static void write_svg_file(struct timechart *tchart, const char *filename)
>  	svg_close();
>  }
>  
> +static void timechart__release(struct timechart *tchart)
> +{
> +	struct per_pid *p = tchart->all_data;
> +	struct power_event *pwr = tchart->power_events;
> +	struct wake_event *we = tchart->wake_events;
> +
> +	while (p) {
> +		struct per_pid *next_pid = p->next;
> +		struct per_pidcomm *c = p->all;
> +
> +		while (c) {
> +			struct per_pidcomm *next_comm = c->next;
> +			struct cpu_sample *cs = c->samples;
> +			struct io_sample *ios = c->io_samples;
> +
> +			while (cs) {
> +				struct cpu_sample *next = cs->next;
> +
> +				free((char *)cs->backtrace);

				zfree()? This way if somebody has a
				pointer to cs and tries to use
				cs->backtrace after this free, it will
				segfault instead of using garbage or
				worse, setting some other unrelated
				struct to some cpu_sample field supposed
				value.

> +				free(cs);
> +				cs = next;
> +			}
> +
> +			while (ios) {
> +				struct io_sample *next = ios->next;
> +
> +				free(ios);

				io->next = NULL;

> +				ios = next;
> +			}
> +
> +			free(c->comm);

			zfree

> +			free(c);
> +			c = next_comm;
> +		}
> +		p = next_pid;
> +	}
> +
> +	while (pwr) {
> +		struct power_event *next = pwr->next;
> +
> +		free(pwr);
		pwr->next = NULL;
> +		pwr = next;
> +	}
> +
> +	while (we) {
> +		struct wake_event *next = we->next;
> +
> +		free((char *)we->backtrace);
		zfree
> +		free(we);
> +		we = next;
> +	}
> +}
> +
>  static int process_header(struct perf_file_section *section __maybe_unused,
>  			  struct perf_header *ph,
>  			  int feat,
> @@ -2079,6 +2132,7 @@ int cmd_timechart(int argc, const char **argv)
>  
>  	ret = __cmd_timechart(&tchart, output_name);
>  out:
> +	timechart__release(&tchart);
>  	zfree(&cpus_cstate_start_times);
>  	zfree(&cpus_cstate_state);
>  	zfree(&cpus_pstate_start_times);
> -- 
> 2.54.0.1032.g2f8565e1d1-goog