1 files changed, 2 insertions, 4 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 24abc1f50dc..a3872f7632e 100644
--- a/arch/x86/xen/mmu.c
+++ b/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
 }