diff --git a/arch/arm/src/armv7-m/up_assert.c b/arch/arm/src/armv7-m/up_assert.c
index b70a567d43..54d5ecafa8 100644
--- a/arch/arm/src/armv7-m/up_assert.c
+++ b/arch/arm/src/armv7-m/up_assert.c
@@ -150,7 +150,7 @@ static void up_taskdump(FAR struct tcb_s *tcb, FAR void *arg)
 #else
   lldbg("PID: %d Stack Used=%lu of %lu\n",
         tcb->pid, (unsigned long)up_check_tcbstack(tcb),
-        unsigned long)tcb->adj_stack_size);
+        (unsigned long)tcb->adj_stack_size);
 #endif
 }
 #endif