diff --git a/[refs] b/[refs]
index 32e0e56083f7..2bc7a89f6910 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 773659483685d652970583384a0294948e57f8b3
+refs/heads/master: 61cca2fab7ecba18f9b9680cd736ef5fa82ad3b1
diff --git a/trunk/arch/x86/xen/mmu.c b/trunk/arch/x86/xen/mmu.c
index 24abc1f50dc5..a3872f7632e8 100644
--- a/trunk/arch/x86/xen/mmu.c
+++ b/trunk/arch/x86/xen/mmu.c
@@ -1721,10 +1721,8 @@ void __init xen_setup_machphys_mapping(void)
 		machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
 	}
 #ifdef CONFIG_X86_32
-	if ((machine_to_phys_mapping + machine_to_phys_nr)
-	    < machine_to_phys_mapping)
-		machine_to_phys_nr = (unsigned long *)NULL
-				     - machine_to_phys_mapping;
+	WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
+		< machine_to_phys_mapping);
 #endif
 }