*** old/src/share/vm/compiler/disassembler.cpp	Fri Feb  5 16:13:48 2016
--- new/src/share/vm/compiler/disassembler.cpp	Fri Feb  5 16:13:48 2016

*** 78,87 ****
--- 78,88 ----
    if (_tried_to_load_library) {
      // Do not try twice.
      // To force retry in debugger: assign _tried_to_load_library=0
      return false;
    }
+ 
    // Try to load it.
    char ebuf[1024];
    char buf[JVM_MAXPATHLEN];
    os::jvm_path(buf, sizeof(buf));
    int jvm_offset = -1;

*** 163,172 ****
--- 164,189 ----
    // Success.
    tty->print_cr("Loaded disassembler from %s", buf);
    return true;
  }
  
+ bool Disassembler::can_decode() {
+   if (_decode_instructions_virtual != NULL || _decode_instructions != NULL) {
+     // Already succeeded.
+     return true;
+   }
+   if (_tried_to_load_library) {
+     // Do not try twice.
+     // To force retry in debugger: assign _tried_to_load_library=0
+     return false;
+   }
+ 
+   // If it was not loaded - lock and load. (double checked)
+   MutexLockerEx locker(DirectivesStack_lock, Mutex::_no_safepoint_check_flag);
+   return Disassembler::load_library();
+ }
+ 
  
  class decode_env {
   private:
    nmethod*      _nm;
    CodeBlob*     _code;

*** 511,522 ****
--- 528,539 ----
                                            options());
  }
  
  
  void Disassembler::decode(CodeBlob* cb, outputStream* st) {
+   if (!can_decode())  return;
    ttyLocker ttyl;
    if (!load_library())  return;
    if (cb->is_nmethod()) {
      decode((nmethod*)cb, st);
      return;
    }
    decode_env env(cb, st);

*** 525,543 ****
--- 542,560 ----
    env.output()->print_cr(" at  [" PTR_FORMAT ", " PTR_FORMAT "]  " JLONG_FORMAT " bytes", p2i(cb->code_begin()), p2i(cb->code_end()), ((jlong)(cb->code_end() - cb->code_begin())) * sizeof(unsigned char*));
    env.decode_instructions(cb->code_begin(), cb->code_end());
  }
  
  void Disassembler::decode(address start, address end, outputStream* st, CodeStrings c) {
+   if (!can_decode())  return;
    ttyLocker ttyl;
    if (!load_library())  return;
    decode_env env(CodeCache::find_blob_unsafe(start), st, c);
    env.decode_instructions(start, end);
  }
  
  void Disassembler::decode(nmethod* nm, outputStream* st) {
+   if (!can_decode())  return;
    ttyLocker ttyl;
    if (!load_library())  return;
    decode_env env(nm, st);
    env.output()->print_cr("----------------------------------------------------------------------");
  
  #ifdef SHARK
    SharkEntry* entry = (SharkEntry *) nm->code_begin();