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

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Message-ID: <4ae75240-0673-5429-2d03-54050e7013c2@linux.ibm.com>
Date:   Thu, 9 Jun 2022 11:09:15 +0530
From:   kajoljain <kjain@...ux.ibm.com>
To:     Ian Rogers <irogers@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Rob Herring <robh@...nel.org>
Cc:     Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v2 1/4] libperf evsel: Open shouldn't leak fd on failure



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@...gle.com>
> ---
>  tools/lib/perf/evsel.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)

Patch looks fine to me

Reviewed-By: Kajol Jain<kjain@...ux.ibm.com>

> 
> 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;
>  }