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From: Ian Rogers <irogers@google.com>
Date: Fri, 10 May 2024 14:27:36 -0700
Message-ID: <CAP-5=fUBQ=GdeQdB25GNtS_ijRxu42W+uz4p6kuykG-8iC1DdA@mail.gmail.com>
Subject: Re: [PATCH 2/2] perf annotate-data: Ensure the number of type histograms
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>, Kan Liang <kan.liang@linux.intel.com>, 
	Jiri Olsa <jolsa@kernel.org>, Adrian Hunter <adrian.hunter@intel.com>, 
	Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, 
	LKML <linux-kernel@vger.kernel.org>, linux-perf-users@vger.kernel.org
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On Fri, May 10, 2024 at 2:04=E2=80=AFPM Namhyung Kim <namhyung@kernel.org> =
wrote:
>
> Arnaldo reported that there is a case where nr_histograms and histograms
> don't agree each other.  It ended up in a segfault trying to access NULL
> histograms array.  Let's make sure to update the nr_histograms when the
> histograms array is changed.
>
> Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/annotate-data.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-d=
ata.c
> index 57e7d4b3550b..965da6c0b542 100644
> --- a/tools/perf/util/annotate-data.c
> +++ b/tools/perf/util/annotate-data.c
> @@ -1800,7 +1800,6 @@ static int alloc_data_type_histograms(struct annota=
ted_data_type *adt, int nr_en
>         sz +=3D sizeof(struct type_hist_entry) * adt->self.size;
>
>         /* Allocate a table of pointers for each event */
> -       adt->nr_histograms =3D nr_entries;
>         adt->histograms =3D calloc(nr_entries, sizeof(*adt->histograms));
>         if (adt->histograms =3D=3D NULL)
>                 return -ENOMEM;
> @@ -1814,6 +1813,8 @@ static int alloc_data_type_histograms(struct annota=
ted_data_type *adt, int nr_en
>                 if (adt->histograms[i] =3D=3D NULL)
>                         goto err;
>         }
> +
> +       adt->nr_histograms =3D nr_entries;
>         return 0;
>
>  err:
> @@ -1827,7 +1828,9 @@ static void delete_data_type_histograms(struct anno=
tated_data_type *adt)
>  {
>         for (int i =3D 0; i < adt->nr_histograms; i++)
>                 zfree(&(adt->histograms[i]));
> +
>         zfree(&adt->histograms);
> +       adt->nr_histograms =3D 0;
>  }
>
>  void annotated_data_type__tree_delete(struct rb_root *root)
> --
> 2.45.0.118.g7fe29c98d7-goog
>