--- old/src/hotspot/share/code/nmethod.cpp	2019-08-27 14:06:19.333123336 +0200
+++ new/src/hotspot/share/code/nmethod.cpp	2019-08-27 14:06:19.036113048 +0200
@@ -50,6 +50,7 @@
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiImpl.hpp"
 #include "runtime/atomic.hpp"
+#include "runtime/deoptimization.hpp"
 #include "runtime/flags/flagSetting.hpp"
 #include "runtime/frame.inline.hpp"
 #include "runtime/handles.inline.hpp"
@@ -1193,11 +1194,7 @@
   // have the Method* live here, in case we unload the nmethod because
   // it is pointing to some oop (other than the Method*) being unloaded.
   if (_method != NULL) {
-    // OSR methods point to the Method*, but the Method* does not
-    // point back!
-    if (_method->code() == this) {
-      _method->clear_code(); // Break a cycle
-    }
+    _method->unlink_code(this);
   }
 
   // Make the class unloaded - i.e., change state and notify sweeper
@@ -1281,16 +1278,9 @@
   }
 }
 
-void nmethod::unlink_from_method(bool acquire_lock) {
-  // We need to check if both the _code and _from_compiled_code_entry_point
-  // refer to this nmethod because there is a race in setting these two fields
-  // in Method* as seen in bugid 4947125.
-  // If the vep() points to the zombie nmethod, the memory for the nmethod
-  // could be flushed and the compiler and vtable stubs could still call
-  // through it.
-  if (method() != NULL && (method()->code() == this ||
-                           method()->from_compiled_entry() == verified_entry_point())) {
-    method()->clear_code(acquire_lock);
+void nmethod::unlink_from_method() {
+  if (method() != NULL) {
+    method()->unlink_code(this);
   }
 }
 
@@ -1317,24 +1307,24 @@
 
   // during patching, depending on the nmethod state we must notify the GC that
   // code has been unloaded, unregistering it. We cannot do this right while
-  // holding the Patching_lock because we need to use the CodeCache_lock. This
+  // holding the CompiledMethod_lock because we need to use the CodeCache_lock. This
   // would be prone to deadlocks.
   // This flag is used to remember whether we need to later lock and unregister.
   bool nmethod_needs_unregister = false;
 
-  {
-    // invalidate osr nmethod before acquiring the patching lock since
-    // they both acquire leaf locks and we don't want a deadlock.
-    // This logic is equivalent to the logic below for patching the
-    // verified entry point of regular methods. We check that the
-    // nmethod is in use to ensure that it is invalidated only once.
-    if (is_osr_method() && is_in_use()) {
-      // this effectively makes the osr nmethod not entrant
-      invalidate_osr_method();
-    }
+  // invalidate osr nmethod before acquiring the patching lock since
+  // they both acquire leaf locks and we don't want a deadlock.
+  // This logic is equivalent to the logic below for patching the
+  // verified entry point of regular methods. We check that the
+  // nmethod is in use to ensure that it is invalidated only once.
+  if (is_osr_method() && is_in_use()) {
+    // this effectively makes the osr nmethod not entrant
+    invalidate_osr_method();
+  }
 
+  {
     // Enter critical section.  Does not block for safepoint.
-    MutexLocker pl(Patching_lock, Mutex::_no_safepoint_check_flag);
+    MutexLocker pl(CompiledMethod_lock, Mutex::_no_safepoint_check_flag);
 
     if (Atomic::load(&_state) >= state) {
       // another thread already performed this transition so nothing
@@ -1389,8 +1379,9 @@
     log_state_change();
 
     // Remove nmethod from method.
-    unlink_from_method(false /* already owns Patching_lock */);
-  } // leave critical region under Patching_lock
+    unlink_from_method();
+
+  } // leave critical region under CompiledMethod_lock
 
 #if INCLUDE_JVMCI
   // Invalidate can't occur while holding the Patching lock