perf header: Fix memory leaks when processing feature headers

These leaks were found with leak sanitizer running "perf pipe recording
and injection test".

In pipe mode feat_fd may hold onto an events struct that needs freeing.

When string features are processed they may overwrite an already created
string, so free this before the overwrite.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20211118201730.2302927-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/header.c

@@ -2321,6 +2321,7 @@ static int perf_header__read_build_ids(struct perf_header *header,
 #define FEAT_PROCESS_STR_FUN(__feat, __feat_env) \
 static int process_##__feat(struct feat_fd *ff, void *data __maybe_unused) \
 {\
+	free(ff->ph->env.__feat_env);		     \
 	ff->ph->env.__feat_env = do_read_string(ff); \
 	return ff->ph->env.__feat_env ? 0 : -ENOMEM; \
 }
@@ -4124,6 +4125,7 @@ int perf_event__process_feature(struct perf_session *session,
 	struct perf_record_header_feature *fe = (struct perf_record_header_feature *)event;
 	int type = fe->header.type;
 	u64 feat = fe->feat_id;
+	int ret = 0;
 
 	if (type < 0 || type >= PERF_RECORD_HEADER_MAX) {
 		pr_warning("invalid record type %d in pipe-mode\n", type);
@@ -4141,11 +4143,13 @@ int perf_event__process_feature(struct perf_session *session,
 	ff.size = event->header.size - sizeof(*fe);
 	ff.ph = &session->header;
 
-	if (feat_ops[feat].process(&ff, NULL))
-		return -1;
+	if (feat_ops[feat].process(&ff, NULL)) {
+		ret = -1;
+		goto out;
+	}
 
 	if (!feat_ops[feat].print || !tool->show_feat_hdr)
-		return 0;
+		goto out;
 
 	if (!feat_ops[feat].full_only ||
 	    tool->show_feat_hdr >= SHOW_FEAT_HEADER_FULL_INFO) {
@@ -4154,8 +4158,9 @@ int perf_event__process_feature(struct perf_session *session,
 		fprintf(stdout, "# %s info available, use -I to display\n",
 			feat_ops[feat].name);
 	}
-
-	return 0;
+out:
+	free_event_desc(ff.events);
+	return ret;
 }
 
 size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)