diff --git a/src/os/bsd/vm/os_bsd.cpp b/src/os/bsd/vm/os_bsd.cpp
index 220a5e74655cc8e45385bae349ce53c136151cd2..83951ff6282aa488de5953024e0b8a041ca4c88b 100644
--- a/src/os/bsd/vm/os_bsd.cpp
+++ b/src/os/bsd/vm/os_bsd.cpp
@@ -3030,6 +3030,19 @@ void os::Bsd::set_signal_handler(int sig, bool set_installed) {
     sigAct.sa_sigaction = signalHandler;
     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
   }
+#if __APPLE__
+  // Needed for main thread as XNU (Mac OS X kernel) will only deliver SIGSEGV
+  // (which starts as SIGBUS) on main thread with faulting address inside "stack+guard pages"
+  // if the signal handler declares it will handle it on alternate stack.
+  // Notice we only declare we will handle it on alt stack, but we are not
+  // actually going to use real alt stack - this is just a workaround.
+  // Please see ux_exception.c, method catch_mach_exception_raise for details
+  // link http://www.opensource.apple.com/source/xnu/xnu-2050.18.24/bsd/uxkern/ux_exception.c
+  if (sig == SIGSEGV) {
+    sigAct.sa_flags |= SA_ONSTACK;
+  }
+#endif
+
   // Save flags, which are set by ours
   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
   sigflags[sig] = sigAct.sa_flags;
diff --git a/src/share/vm/runtime/thread.hpp b/src/share/vm/runtime/thread.hpp
index d64ca311c65aba62b5c6296c120b774a3e7c9e9c..71007590bbf2305d52791defd4dc82e4bc573922 100644
--- a/src/share/vm/runtime/thread.hpp
+++ b/src/share/vm/runtime/thread.hpp
@@ -638,9 +638,6 @@ public:
   jint _hashStateZ ;
   void * _schedctl ;
 
-  intptr_t _ScratchA, _ScratchB ;              // Scratch locations for fast-path sync code
-  static ByteSize ScratchA_offset()            { return byte_offset_of(Thread, _ScratchA ); }
-  static ByteSize ScratchB_offset()            { return byte_offset_of(Thread, _ScratchB ); }
 
   volatile jint rng [4] ;                      // RNG for spin loop