perf intel-pt: Fix next 'err' value, walking trace

commit a32e6c5da599dbf49e60622a4dfb5b9b40ece029 upstream.

Code after label 'next:' in intel_pt_walk_trace() assumes 'err' is zero,
but it may not be, if arrived at via a 'goto'. Ensure it is zero.

Fixes: 7c1b16ba0e26e6 ("perf intel-pt: Add support for decoding FUP/TIP only")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v5.15+
Link: https://lore.kernel.org/r/20211210162303.2288710-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[Adrian: Backport to v5.10]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 27a3c3e..aaae2ef 100644 (file)
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -2068,6 +2068,7 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
                if (err)
                        return err;
 next:
+               err = 0;
                if (decoder->cyc_threshold) {
                        if (decoder->sample_cyc && last_packet_type != INTEL_PT_CYC)
                                decoder->sample_cyc = false;