Re: [PATCH 01/20] perf nsinfo: fix refcounting

From: Arnaldo Carvalho de Melo
Date: Thu Jul 15 2021 - 15:19:16 EST


Em Thu, Jul 15, 2021 at 06:07:06PM +0200, Riccardo Mancini escreveu:
> ASan reports a memory leak of nsinfo during the execution of the perf
> test "31: Lookup mmap thread".
> The leak is caused by a refcounted variable being replaced without
> dropping the refcount.
>
> This patch makes sure that the refcnt of nsinfo is decreased whenever
> a refcounted variable is replaced with a new value.

So, there are multiple fixes in just one patch, I'll split it into
three, no need to resend.

I'll try and check if finding Fixes: for the three is easy, that way
stable@xxxxxxxxxxxxxxx will figure out which of the supported releases
need each of them.

- Arnaldo

> Signed-off-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
> ---
> tools/perf/builtin-inject.c | 5 +++--
> tools/perf/util/map.c | 2 ++
> tools/perf/util/probe-event.c | 4 +++-
> 3 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index 5d6f583e2cd35be0..ffd2b25039e36e1d 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -361,9 +361,10 @@ static struct dso *findnew_dso(int pid, int tid, const char *filename,
> dso = machine__findnew_dso_id(machine, filename, id);
> }
>
> - if (dso)
> + if (dso) {
> + nsinfo__put(dso->nsinfo);
> dso->nsinfo = nsi;
> - else
> + } else
> nsinfo__put(nsi);
>
> thread__put(thread);
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index 8af693d9678cefe0..72e7f3616157ead4 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -192,6 +192,8 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
> if (!(prot & PROT_EXEC))
> dso__set_loaded(dso);
> }
> +
> + nsinfo__put(dso->nsinfo);
> dso->nsinfo = nsi;
>
> if (build_id__is_defined(bid))
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index c14e1d228e56b1c6..e05750cea34c3a95 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -179,8 +179,10 @@ struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user)
> struct map *map;
>
> map = dso__new_map(target);
> - if (map && map->dso)
> + if (map && map->dso) {
> + nsinfo__put(map->dso->nsinfo);
> map->dso->nsinfo = nsinfo__get(nsi);
> + }
> return map;
> } else {
> return kernel_get_module_map(target);
> --
> 2.31.1
>

--

- Arnaldo