Re: [PATCH v2 1/4] libperf evsel: Open shouldn't leak fd on failure

From: kajoljain
Date: Thu Jun 09 2022 - 01:39:52 EST




On 6/9/22 10:53, Ian Rogers wrote:
> If the perf_event_open fails the fd is opened but the fd is only freed
> by closing (not by delete). Typically when an open fails you don't call
> close and so this results in a memory leak. To avoid this, add a close
> when open fails.
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> tools/lib/perf/evsel.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)

Patch looks fine to me

Reviewed-By: Kajol Jain<kjain@xxxxxxxxxxxxx>

>
> diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
> index c1d58673f6ef..952f3520d5c2 100644
> --- a/tools/lib/perf/evsel.c
> +++ b/tools/lib/perf/evsel.c
> @@ -149,23 +149,30 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
> int fd, group_fd, *evsel_fd;
>
> evsel_fd = FD(evsel, idx, thread);
> - if (evsel_fd == NULL)
> - return -EINVAL;
> + if (evsel_fd == NULL) {
> + err = -EINVAL;
> + goto out;
> + }
>
> err = get_group_fd(evsel, idx, thread, &group_fd);
> if (err < 0)
> - return err;
> + goto out;
>
> fd = sys_perf_event_open(&evsel->attr,
> threads->map[thread].pid,
> cpu, group_fd, 0);
>
> - if (fd < 0)
> - return -errno;
> + if (fd < 0) {
> + err = -errno;
> + goto out;
> + }
>
> *evsel_fd = fd;
> }
> }
> +out:
> + if (err)
> + perf_evsel__close(evsel);
>
> return err;
> }