diff --git a/src/mididevice.cpp b/src/mididevice.cpp
index 9762e49..6959b41 100644
--- a/src/mididevice.cpp
+++ b/src/mididevice.cpp
@@ -163,6 +163,8 @@ void CMIDIDevice::MIDIMessageHandler (const u8 *pMessage, size_t nLength, unsign
 		return;
 	}
 
+	m_MIDISpinLock.Acquire ();
+
 	u8 ucStatus  = pMessage[0];
 	u8 ucChannel = ucStatus & 0x0F;
 	u8 ucType    = ucStatus >> 4;
@@ -313,6 +315,7 @@ void CMIDIDevice::MIDIMessageHandler (const u8 *pMessage, size_t nLength, unsign
 			}
 		}
 	}
+	m_MIDISpinLock.Release ();
 }
 
 void CMIDIDevice::AddDevice (const char *pDeviceName)
diff --git a/src/mididevice.h b/src/mididevice.h
index 196a61b..1bd5396 100644
--- a/src/mididevice.h
+++ b/src/mididevice.h
@@ -27,6 +27,7 @@
 #include <string>
 #include <unordered_map>
 #include <circle/types.h>
+#include <circle/spinlock.h>
 
 class CMiniDexed;
 
@@ -65,6 +66,8 @@ private:
 
 	typedef std::unordered_map<std::string, CMIDIDevice *> TDeviceMap;
 	static TDeviceMap s_DeviceMap;
+
+	CSpinLock m_MIDISpinLock;
 };
 
 #endif