diff --git a/libraries/AP_Vehicle/AP_Vehicle.h b/libraries/AP_Vehicle/AP_Vehicle.h
index e5418bb673..3d0c221d4f 100644
--- a/libraries/AP_Vehicle/AP_Vehicle.h
+++ b/libraries/AP_Vehicle/AP_Vehicle.h
@@ -127,6 +127,8 @@ public:
     };
 
     void get_common_scheduler_tasks(const AP_Scheduler::Task*& tasks, uint8_t& num_tasks);
+    // implementations *MUST* fill in all passed-in fields or we get
+    // Valgrind errors
     virtual void get_scheduler_tasks(const AP_Scheduler::Task *&tasks, uint8_t &task_count, uint32_t &log_bit) = 0;
 
     /*