--- old/src/share/vm/oops/instanceKlass.cpp	2014-10-14 09:38:29.465638289 +0200
+++ new/src/share/vm/oops/instanceKlass.cpp	2014-10-14 09:38:29.385638293 +0200
@@ -2780,18 +2780,18 @@
 void InstanceKlass::add_osr_nmethod(nmethod* n) {
   // only one compilation can be active
   NEEDS_CLEANUP
-  // This is a short non-blocking critical region, so the no safepoint check is ok.
-  OsrList_lock->lock_without_safepoint_check();
-  assert(n->is_osr_method(), "wrong kind of nmethod");
-  n->set_osr_link(osr_nmethods_head());
-  set_osr_nmethods_head(n);
-  // Raise the highest osr level if necessary
-  if (TieredCompilation) {
-    Method* m = n->method();
-    m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
+  {
+    // This is a short non-blocking critical region, so the no safepoint check is ok.
+    MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
+    assert(n->is_osr_method(), "wrong kind of nmethod");
+    n->set_osr_link(osr_nmethods_head());
+    set_osr_nmethods_head(n);
+    // Raise the highest osr level if necessary
+    if (TieredCompilation) {
+      Method* m = n->method();
+      m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
+    }
   }
-  // Remember to unlock again
-  OsrList_lock->unlock();
 
   // Get rid of the osr methods for the same bci that have lower levels.
   if (TieredCompilation) {
@@ -2807,7 +2807,7 @@
 
 void InstanceKlass::remove_osr_nmethod(nmethod* n) {
   // This is a short non-blocking critical region, so the no safepoint check is ok.
-  OsrList_lock->lock_without_safepoint_check();
+  MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
   assert(n->is_osr_method(), "wrong kind of nmethod");
   nmethod* last = NULL;
   nmethod* cur  = osr_nmethods_head();
@@ -2844,13 +2844,11 @@
     }
     m->set_highest_osr_comp_level(max_level);
   }
-  // Remember to unlock again
-  OsrList_lock->unlock();
 }
 
 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
   // This is a short non-blocking critical region, so the no safepoint check is ok.
-  OsrList_lock->lock_without_safepoint_check();
+  MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
   nmethod* osr = osr_nmethods_head();
   nmethod* best = NULL;
   while (osr != NULL) {
@@ -2866,14 +2864,12 @@
       if (match_level) {
         if (osr->comp_level() == comp_level) {
           // Found a match - return it.
-          OsrList_lock->unlock();
           return osr;
         }
       } else {
         if (best == NULL || (osr->comp_level() > best->comp_level())) {
           if (osr->comp_level() == CompLevel_highest_tier) {
             // Found the best possible - return it.
-            OsrList_lock->unlock();
             return osr;
           }
           best = osr;
@@ -2882,7 +2878,6 @@
     }
     osr = osr->osr_link();
   }
-  OsrList_lock->unlock();
   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
     return best;
   }