From 239dc400325fa530316fbc40a60987eca353ff89 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Sun, 14 Apr 2019 22:11:20 +0200
Subject: [PATCH] device: fix crash when unplugging certain devices on macOS

Fixes #621
---
 panda/src/device/ioKitInputDevice.cxx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/panda/src/device/ioKitInputDevice.cxx b/panda/src/device/ioKitInputDevice.cxx
index da1369932e..8468fd4816 100644
--- a/panda/src/device/ioKitInputDevice.cxx
+++ b/panda/src/device/ioKitInputDevice.cxx
@@ -22,8 +22,11 @@
 #include "mouseButton.h"
 
 static void removal_callback(void *ctx, IOReturn result, void *sender) {
-  IOKitInputDevice *input_device = (IOKitInputDevice *)ctx;
+  // We need to hold a reference to this because it may otherwise be destroyed
+  // during the call to on_remove().
+  PT(IOKitInputDevice) input_device = (IOKitInputDevice *)ctx;
   nassertv(input_device != nullptr);
+  nassertv(input_device->test_ref_count_integrity());
   input_device->on_remove();
 }