diff --git a/sched/semaphore/sem_tickwait.c b/sched/semaphore/sem_tickwait.c
index 9f219bc571..afd4aef9d4 100644
--- a/sched/semaphore/sem_tickwait.c
+++ b/sched/semaphore/sem_tickwait.c
@@ -68,12 +68,10 @@
 
 int nxsem_tickwait(FAR sem_t *sem, uint32_t delay)
 {
-  FAR struct tcb_s *rtcb = this_task();
+  FAR struct tcb_s *rtcb;
   irqstate_t flags;
   int ret;
 
-  DEBUGASSERT(sem != NULL && up_interrupt_context() == false);
-
   /* We will disable interrupts until we have completed the semaphore
    * wait.  We need to do this (as opposed to just disabling pre-emption)
    * because there could be interrupt handlers that are asynchronously
@@ -106,6 +104,8 @@ int nxsem_tickwait(FAR sem_t *sem, uint32_t delay)
       goto out;
     }
 
+  rtcb = this_task();
+
   /* Start the watchdog with interrupts still disabled */
 
   wd_start(&rtcb->waitdog, delay, nxsem_timeout, (uintptr_t)rtcb);