diff --git a/xen/arch/x86/oprofile/xenoprof.c b/xen/arch/x86/oprofile/xenoprof.c
index b926b19e6d..c00f193c26 100644
--- a/xen/arch/x86/oprofile/xenoprof.c
+++ b/xen/arch/x86/oprofile/xenoprof.c
@@ -25,7 +25,7 @@ int xenoprof_arch_counter(XEN_GUEST_HANDLE(void) arg)
     if ( copy_from_guest(&counter, arg, 1) )
         return -EFAULT;
 
-    if ( counter.ind > OP_MAX_COUNTER )
+    if ( counter.ind >= OP_MAX_COUNTER )
         return -E2BIG;
 
     counter_config[counter.ind].count     = counter.count;
@@ -63,7 +63,7 @@ int compat_oprof_arch_counter(XEN_GUEST_HANDLE(void) arg)
     if ( copy_from_guest(&counter, arg, 1) )
         return -EFAULT;
 
-    if ( counter.ind > OP_MAX_COUNTER )
+    if ( counter.ind >= OP_MAX_COUNTER )
         return -E2BIG;
 
     counter_config[counter.ind].count     = counter.count;