--- old/src/os/linux/vm/os_linux.cpp	2018-01-26 00:12:32.100196990 -0500
+++ new/src/os/linux/vm/os_linux.cpp	2018-01-26 00:12:32.046196993 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -946,8 +946,8 @@
     }
   }
 
-  if (os::Linux::is_initial_thread()) {
-    // If current thread is initial thread, its stack is mapped on demand,
+  if (os::is_primordial_thread()) {
+    // If current thread is primordial thread, its stack is mapped on demand,
     // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
     // the entire stack region to avoid SEGV in stack banging.
     // It is also useful to get around the heap-stack-gap problem on SuSE
@@ -1032,21 +1032,24 @@
 }
 
 //////////////////////////////////////////////////////////////////////////////
-// initial thread
+// primordial thread
 
-// Check if current thread is the initial thread, similar to Solaris thr_main.
-bool os::Linux::is_initial_thread(void) {
+// Check if current thread is the primordial thread, similar to Solaris thr_main.
+bool os::is_primordial_thread(void) {
   char dummy;
   // If called before init complete, thread stack bottom will be null.
   // Can be called if fatal error occurs before initialization.
-  if (initial_thread_stack_bottom() == NULL) return false;
-  assert(initial_thread_stack_bottom() != NULL &&
-         initial_thread_stack_size()   != 0,
-         "os::init did not locate initial thread's stack region");
-  if ((address)&dummy >= initial_thread_stack_bottom() &&
-      (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
+  if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
+  assert(os::Linux::initial_thread_stack_bottom() != NULL &&
+         os::Linux::initial_thread_stack_size()   != 0,
+         "os::init did not locate primordial thread's stack region");
+  if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
+      (address)&dummy < os::Linux::initial_thread_stack_bottom() +
+                        os::Linux::initial_thread_stack_size()) {
        return true;
-  else return false;
+  } else {
+       return false;
+  }
 }
 
 // Find the virtual memory area that contains addr
@@ -1073,7 +1076,7 @@
   return false;
 }
 
-// Locate initial thread stack. This special handling of initial thread stack
+// Locate primordial thread stack. This special handling of primordial thread stack
 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
 // bogus value for the primordial process thread. While the launcher has created
 // the VM in a new thread since JDK 6, we still have to allow for the use of the
@@ -1097,7 +1100,10 @@
   // 6308388: a bug in ld.so will relocate its own .data section to the
   //   lower end of primordial stack; reduce ulimit -s value a little bit
   //   so we won't install guard page on ld.so's data section.
-  stack_size -= 2 * page_size();
+  //   But ensure we don't underflow the stack size - allow 1 page spare
+  if (stack_size >= (size_t)(3 * page_size())) {
+    stack_size -= 2 * page_size();
+  }
 
   // Try to figure out where the stack base (top) is. This is harder.
   //
@@ -1218,16 +1224,16 @@
 
       if (i != 28 - 2) {
          assert(false, "Bad conversion from /proc/self/stat");
-         // product mode - assume we are the initial thread, good luck in the
+         // product mode - assume we are the primordial thread, good luck in the
          // embedded case.
-         warning("Can't detect initial thread stack location - bad conversion");
+         warning("Can't detect primordial thread stack location - bad conversion");
          stack_start = (uintptr_t) &rlim;
       }
     } else {
       // For some reason we can't open /proc/self/stat (for example, running on
       // FreeBSD with a Linux emulator, or inside chroot), this should work for
       // most cases, so don't abort:
-      warning("Can't detect initial thread stack location - no /proc/self/stat");
+      warning("Can't detect primordial thread stack location - no /proc/self/stat");
       stack_start = (uintptr_t) &rlim;
     }
   }
@@ -1247,7 +1253,7 @@
     stack_top = (uintptr_t)high;
   } else {
     // failed, likely because /proc/self/maps does not exist
-    warning("Can't detect initial thread stack location - find_vma failed");
+    warning("Can't detect primordial thread stack location - find_vma failed");
     // best effort: stack_start is normally within a few pages below the real
     // stack top, use it as stack top, and reduce stack size so we won't put
     // guard page outside stack.
@@ -3066,11 +3072,11 @@
 // where we're going to put our guard pages, truncate the mapping at
 // that point by munmap()ping it.  This ensures that when we later
 // munmap() the guard pages we don't leave a hole in the stack
-// mapping. This only affects the main/initial thread
+// mapping. This only affects the main/primordial thread
 
 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
 
-  if (os::Linux::is_initial_thread()) {
+  if (os::is_primordial_thread()) {
     // As we manually grow stack up to bottom inside create_attached_thread(),
     // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
     // we don't need to do anything special.
@@ -3095,14 +3101,14 @@
 
 // If this is a growable mapping, remove the guard pages entirely by
 // munmap()ping them.  If not, just call uncommit_memory(). This only
-// affects the main/initial thread, but guard against future OS changes
-// It's safe to always unmap guard pages for initial thread because we
-// always place it right after end of the mapped region
+// affects the main/primordial thread, but guard against future OS changes.
+// It's safe to always unmap guard pages for primordial thread because we
+// always place it right after end of the mapped region.
 
 bool os::remove_stack_guard_pages(char* addr, size_t size) {
   uintptr_t stack_extent, stack_base;
 
-  if (os::Linux::is_initial_thread()) {
+  if (os::is_primordial_thread()) {
     return ::munmap(addr, size) == 0;
   }
 
@@ -4877,10 +4883,9 @@
   }
 }
 
-// this is called _before_ the most of global arguments have been parsed
+// this is called _before_ most of the global arguments have been parsed
 void os::init(void) {
   char dummy;   /* used to get a guess on initial stack address */
-//  first_hrtime = gethrtime();
 
   // With LinuxThreads the JavaMain thread pid (primordial thread)
   // is different than the pid of the java launcher thread.
@@ -4907,7 +4912,7 @@
 
   Linux::initialize_system_info();
 
-  // main_thread points to the aboriginal thread
+  // _main_thread points to the thread that created/loaded the JVM.
   Linux::_main_thread = pthread_self();
 
   Linux::clock_init();