diff --git a/core/msg.c b/core/msg.c
index a46875f16e8b354042d693d894dbfa6961aae587..86ee0dd287ae61ee6e4a42d633c85ab0412fc97f 100644
--- a/core/msg.c
+++ b/core/msg.c
@@ -330,6 +330,7 @@ static int _msg_receive(msg_t *m, int block)
             thread_yield_higher();
 
             /* sender copied message */
+            assert(sched_active_thread->status != STATUS_RECEIVE_BLOCKED);
         }
         else {
             irq_restore(state);