perf bpf: Return NULL when RB tree lookup fails in perf_env__find_bpf_prog_info()

We currently don't return NULL in case we don't find the
bpf_prog_info_node, fixing that.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e4378f0cb9 ("perf bpf: Save bpf_prog_info in a rbtree in perf_env")
Link: http://lkml.kernel.org/r/20190416134151.15282-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/env.c

@@ -57,9 +57,11 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
 		else if (prog_id > node->info_linear->info.id)
 			n = n->rb_right;
 		else
-			break;
+			goto out;
 	}
+	node = NULL;
 
+out:
 	up_read(&env->bpf_progs.lock);
 	return node;
 }