--- a/hotspot/src/os/windows/vm/os_windows.cpp	Mon Aug 18 14:37:55 2014 +0200
+++ b/hotspot/src/os/windows/vm/os_windows.cpp	Wed Nov 04 17:18:59 2015 -0500
@@ -1608,6 +1608,15 @@
   if (nl != NULL) *nl = '\0';
 }
 
+int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
+  int ret = vsnprintf(buf, len, fmt, args);
+  // Get the correct buffer size if buf is too small
+  if (ret < 0) {
+    return _vscprintf(fmt, args);
+  }
+  return ret;
+}
+
 void os::print_os_info_brief(outputStream* st) {
   os::print_os_info(st);
 }