diff --git a/arch/x86_64/src/intel64/up_initialstate.c b/arch/x86_64/src/intel64/up_initialstate.c
index 3f4d0c8652..a727b9b1ec 100644
--- a/arch/x86_64/src/intel64/up_initialstate.c
+++ b/arch/x86_64/src/intel64/up_initialstate.c
@@ -85,6 +85,7 @@ void up_initial_state(struct tcb_s *tcb)
   /* set page table to share space with current process */
 
   rtcb = this_task();
+  UNUSED(rtcb);
 
   /* Save the initial stack pointer... the value of the stackpointer before
    * the "interrupt occurs."