Re: [PATCH 1/1] perf dlfilter: Initialize addr_location before passing it to thread__find_symbol_fb()

[Ian Rogers]

On Mon, Jul 24, 2023 at 2:09 PM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> 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 functions")
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> Cc: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
> Cc: Disha Goel <disgoel@xxxxxxxxxxxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Kajol Jain <kjain@xxxxxxxxxxxxx>
> Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Link: https://lore.kernel.org/lkml/
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
>  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, __u64 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
>