diff -r 9c2ecc2ffb12 -r 1fdb98a17101 src/share/vm/runtime/os.cpp
--- a/src/share/vm/runtime/os.cpp	Fri Jul 11 01:14:44 2008 -0700
+++ b/src/share/vm/runtime/os.cpp	Sat Jul 19 17:38:22 2008 -0400
@@ -922,8 +922,9 @@
   // time and expensive page trap spinning, 'SerializePageLock' is used to block
   // the mutator thread if such case is encountered. See bug 6546278 for details.
   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
-  os::protect_memory( (char *)os::get_memory_serialize_page(), os::vm_page_size() );
-  os::unguard_memory( (char *)os::get_memory_serialize_page(), os::vm_page_size() );
+  os::protect_memory((char *)os::get_memory_serialize_page(),
+                     os::vm_page_size(), MEM_PROT_READ, /*is_committed*/true );
+  os::unguard_memory((char *)os::get_memory_serialize_page(), os::vm_page_size());
   Thread::muxRelease(&SerializePageLock);
 }