Mutex Not Held During List Size Check

src/reHDD.cpp

@@ -92,16 +92,19 @@ void reHDD::app_logic(void)
 
 Drive *reHDD::getSelectedDrive()
 {
+    mxDrives.lock();
     if (u16SelectedEntry < listDrives.size())
     {
         list<Drive>::iterator it = listDrives.begin();
         advance(it, u16SelectedEntry);
         it->u16DriveIndex = u16SelectedEntry;
+        mxDrives.unlock();
         return &(*it);
     }
     else
     {
         Logger::logThis()->warning("selected drive not present");
+        mxDrives.unlock();
         return nullptr;
     }
 }