diff -r 6c97c830fb6f -r 328926869b15 src/share/vm/oops/methodOop.cpp
--- a/src/share/vm/oops/methodOop.cpp	Sat Apr 09 21:16:12 2011 -0700
+++ b/src/share/vm/oops/methodOop.cpp	Sat Apr 09 22:55:25 2011 -0700
@@ -921,6 +921,10 @@
     tty->cr();
   }
 
+  // invariant:   cp->symbol_at_put is preceded by a refcount increment (more usually a lookup)
+  name->increment_refcount();
+  signature->increment_refcount();
+
   constantPoolHandle cp;
   {
     constantPoolOop cp_oop = oopFactory::new_constantPool(_imcp_limit, IsSafeConc, CHECK_(empty));