diff -r 9ca9331c9780 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h	Fri Jan 21 15:37:36 2011 +0000
+++ b/xen/include/asm-x86/p2m.h	Fri Jan 21 16:41:58 2011 +0000
@@ -390,7 +390,14 @@
                                       must_succeed 
                                       ? MEM_SHARING_MUST_SUCCEED : 0) )
         {
-            BUG_ON(must_succeed);
+            if ( must_succeed
+                 && p2m->domain->is_dying )
+            {
+                mfn = INVALID_MFN;
+                *p2mt=p2m_invalid;
+            }
+            else
+                BUG_ON(must_succeed);
             return mfn;
         }
         mfn = gfn_to_mfn(p2m, gfn, p2mt);