--- old/src/share/vm/runtime/thread.cpp	Thu May 12 16:30:52 2011
+++ new/src/share/vm/runtime/thread.cpp	Thu May 12 16:30:52 2011
@@ -2942,6 +2942,7 @@
   _queue = queue;
   _counters = counters;
   _buffer_blob = NULL;
+  _scanned_nmethod = NULL;
 
 #ifndef PRODUCT
   _ideal_graph_printer = NULL;
@@ -2948,6 +2949,15 @@
 #endif
 }
 
+void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
+  JavaThread::oops_do(f, cf);
+  if (_scanned_nmethod != NULL && cf != NULL) {
+    // Safepoints can occur when the sweeper is scanning an nmethod so
+    // process it here to make sure it isn't unloaded in the middle of
+    // a scan.
+    cf->do_code_blob(_scanned_nmethod);
+  }
+}
 
 // ======= Threads ========