linux-kernel - Re: [PATCH 06/20] perf dso: fix memory leak in dso__new

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Date:   Thu, 15 Jul 2021 17:01:57 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Riccardo Mancini <rickyman7@...il.com>
Cc:     Ian Rogers <irogers@...gle.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 06/20] perf dso: fix memory leak in dso__new_map

Em Thu, Jul 15, 2021 at 06:07:11PM +0200, Riccardo Mancini escreveu:
> ASan reports a memory leak when running the perf test
> "65: maps__merge_in". The causes of the leaks are two, this patch
> addresses only the first one, which is related to dso__new_map.
> The bug is that dso__new_map creates a new dso but never decreases
> the refcount it gets from creating it.
> 
> This patch adds the missing dso__put.

Thanks, applied.

This needs some extra thinking for some unrelated issue, namely that
this dso isn't linked in the machine dso list, I think this is only used
by 'perf probe' :-\

I guess this won't be a problem since using the machine dso list is
important just for other tools, like when traversing to get the
build-ids, etc.

- Arnaldo
 
> Signed-off-by: Riccardo Mancini <rickyman7@...il.com>
> ---
>  tools/perf/util/dso.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index d786cf6b0cfa65f2..ee15db2be2f43403 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -1154,8 +1154,10 @@ struct map *dso__new_map(const char *name)
>  	struct map *map = NULL;
>  	struct dso *dso = dso__new(name);
>  
> -	if (dso)
> +	if (dso) {
>  		map = map__new2(0, dso);
> +		dso__put(dso);
> +	}
>  
>  	return map;
>  }
> -- 
> 2.31.1
> 

-- 

- Arnaldo