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From:   Ian Rogers <irogers@google.com>
Date:   Mon, 24 Jul 2023 14:16:05 -0700
Message-ID: <CAP-5=fVy8cYrYH5EmdrJo0+q0CHj=chTxWYkieLi6LwTSjFCAQ@mail.gmail.com>
Subject: Re: [PATCH 1/1] perf dlfilter: Initialize addr_location before
 passing it to thread__find_symbol_fb()
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Disha Goel <disgoel@linux.vnet.ibm.com>,
        Jiri Olsa <jolsa@kernel.org>, Kajol Jain <kjain@linux.ibm.com>,
        Madhavan Srinivasan <maddy@linux.ibm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Jul 24, 2023 at 2:09=E2=80=AFPM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> As thread__find_symbol_fb() will end up calling thread__find_map() and
> it in turn will call these on uninitialized memory:
>
>         maps__zput(al->maps);
>         map__zput(al->map);
>         thread__zput(al->thread);

Normally there would be a addr_location__exit. It looks here like most
values are copied in al_to_d_al, which copies reference counted values
without doing appropriate gets. Perhaps add the gets in al_to_d_al and
add the exit to make it clear there can't be addr_location related
leaks here.

Thanks,
Ian

> Fixes: 0dd5041c9a0eaf8c ("perf addr_location: Add init/exit/copy function=
s")
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
> Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kajol Jain <kjain@linux.ibm.com>
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Link: https://lore.kernel.org/lkml/
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/perf/util/dlfilter.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/tools/perf/util/dlfilter.c b/tools/perf/util/dlfilter.c
> index 46f74b2344dbb34c..798a53d7e6c9dfc5 100644
> --- a/tools/perf/util/dlfilter.c
> +++ b/tools/perf/util/dlfilter.c
> @@ -166,6 +166,7 @@ static __s32 dlfilter__resolve_address(void *ctx, __u=
64 address, struct perf_dlf
>         if (!thread)
>                 return -1;
>
> +       addr_location__init(&al);
>         thread__find_symbol_fb(thread, d->sample->cpumode, address, &al);
>
>         al_to_d_al(&al, &d_al);
> --
> 2.37.1
>