--- old/src/share/vm/prims/jvm.cpp	2018-07-13 12:03:29.291290740 -0700
+++ new/src/share/vm/prims/jvm.cpp	2018-07-13 12:03:29.168279702 -0700
@@ -2915,10 +2915,11 @@
 
 ATTRIBUTE_PRINTF(3, 0)
 int jio_vsnprintf(char *str, size_t count, const char *fmt, va_list args) {
-  // see bug 4399518, 4417214
+  // Reject count values that are negative signed values converted to
+  // unsigned; see bug 4399518, 4417214
   if ((intptr_t)count <= 0) return -1;
 
-  int result = vsnprintf(str, count, fmt, args);
+  int result = os::vsnprintf(str, count, fmt, args);
   // Note: on truncation vsnprintf(3) on Unix returns number of
   // characters which would have been written had the buffer been large
   // enough; on Windows, it returns -1. We handle both cases here and