Re: [PATCH v2 06/18] perf buildid-cache: Fix use of uninitialized value

[Namhyung Kim]

On Thu, Oct 5, 2023 at 4:09 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> The buildid filename is first determined and then from this the
> buildid read. If getting the filename fails then the buildid will be
> used for a later memcmp uninitialized. Detected by clang-tidy.
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
>  tools/perf/builtin-buildid-cache.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
> index cd381693658b..e2a40f1d9225 100644
> --- a/tools/perf/builtin-buildid-cache.c
> +++ b/tools/perf/builtin-buildid-cache.c
> @@ -277,8 +277,10 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
>         char filename[PATH_MAX];
>         struct build_id bid;
>
> -       if (dso__build_id_filename(dso, filename, sizeof(filename), false) &&
> -           filename__read_build_id(filename, &bid) == -1) {
> +       if (!dso__build_id_filename(dso, filename, sizeof(filename), false))
> +               return true;

This won't print anything and ignore the file which changes
the existing behavior.  But if it fails to read the build-id, I
don't think there is not much we can do with it.  IIUC the
original intention of -M/--missing option is to list files that
have a build-id but it's not in the build-id cache.  So maybe
it's ok to silently ignore it.

Thanks,
Namhyung


> +
> +       if (filename__read_build_id(filename, &bid) == -1) {
>                 if (errno == ENOENT)
>                         return false;
>
> --
> 2.42.0.609.gbb76f46606-goog
>