Update syscall.c

userprog/syscall.c

@@ -69,7 +69,7 @@ syscall_handler (struct intr_frame *f UNUSED)
     break;
   default:
     printf ("WARNING: Invalid Syscall (%d)\n", syscall_number);
+    thread_exit ();
   }
   // TODO: remove this call to exit as we don't want all syscalls to make the thread exit
-  thread_exit ();
 }