From a6c39dee84fc7ac0ba88fc002a9fdf4d961ef794 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 7 Jan 2016 08:33:33 +1100
Subject: [PATCH] AP_NavEKF: don't allocate EKF1 unless it will leave 4k free
 memory

---
 libraries/AP_NavEKF/AP_NavEKF.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libraries/AP_NavEKF/AP_NavEKF.cpp b/libraries/AP_NavEKF/AP_NavEKF.cpp
index a2c631a94e..0a3c97ebdf 100644
--- a/libraries/AP_NavEKF/AP_NavEKF.cpp
+++ b/libraries/AP_NavEKF/AP_NavEKF.cpp
@@ -421,6 +421,11 @@ bool NavEKF::InitialiseFilterDynamic(void)
         return false;
     }
     if (core == nullptr) {
+        if (hal.util->available_memory() < 4096 + sizeof(*core)) {
+            _enable.set(0);
+            GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_CRITICAL, "NavEKF: not enough memory");
+            return false;
+        }
         core = new NavEKF_core(*this, _ahrs, _baro, _rng);
         if (core == nullptr) {
             _enable.set(0);