src/share/vm/code/nmethod.cpp

rev 5099 : 8016277: Crash in nmethod::is_compiled_by_c1() on x86
Summary: Method pointer for zombie methods may be invalid
Reviewed-by:

*** 91,112 ****
  #define DTRACE_METHOD_UNLOAD_PROBE(method)
  
  #endif
  
  bool nmethod::is_compiled_by_c1() const {
!   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
!   if (is_native_method()) return false;
    return compiler()->is_c1();
  }
  bool nmethod::is_compiled_by_c2() const {
!   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
!   if (is_native_method()) return false;
    return compiler()->is_c2();
  }
  bool nmethod::is_compiled_by_shark() const {
!   if (is_native_method()) return false;
!   assert(compiler() != NULL, "must be");
    return compiler()->is_shark();
  }
  
  
  
--- 91,115 ----
  #define DTRACE_METHOD_UNLOAD_PROBE(method)
  
  #endif
  
  bool nmethod::is_compiled_by_c1() const {
!   if (compiler() == NULL)  return false;
!   // method() == NULL can happen during debug printing or if the nmethod is zombie
!   assert(method() == NULL || !is_native_method(), "native methods have no compiler");
    return compiler()->is_c1();
  }
  bool nmethod::is_compiled_by_c2() const {
!   if (compiler() == NULL)  return false;
!   // method() == NULL can happen during debug printing or if the nmethod is zombie
!   assert(method() == NULL || !is_native_method(), "native methods have no compiler");
    return compiler()->is_c2();
  }
  bool nmethod::is_compiled_by_shark() const {
!   if (compiler() == NULL)  return false;
!   // method() == NULL can happen during debug printing or if the nmethod is zombie
!   assert(method() == NULL || !is_native_method(), "native methods have no compiler");
    return compiler()->is_shark();
  }
  
  
  
*** 1380,1389 ****
--- 1383,1394 ----
  #ifdef ASSERT
      // It's no longer safe to access the oops section since zombie
      // nmethods aren't scanned for GC.
      _oops_are_stale = true;
  #endif
+     _method = NULL; // the Method may be reclaimed by class unloading
+                     // now that the nmethod is in zombie state
    } else {
      assert(state == not_entrant, "other cases may need to be handled differently");
    }
  
    if (TraceCreateZombies) {