[Kernel] Fix the compiling warning
@@ -147,7 +147,7 @@ static void _signal_deliver(rt_thread_t tid)
rt_sighandler_t rt_signal_install(int signo, rt_sighandler_t handler)
{
- rt_sighandler_t old;
+ rt_sighandler_t old = RT_NULL;
rt_thread_t tid = rt_thread_self();
if (!sig_valid(signo)) return SIG_ERR;
