diff --git a/src/xkb/XKBExtDev.c b/src/xkb/XKBExtDev.c
index a3e671df..162cc356 100644
--- a/src/xkb/XKBExtDev.c
+++ b/src/xkb/XKBExtDev.c
@@ -188,8 +188,7 @@ _XkbReadGetDeviceInfoReply(Display *dpy,
             return tmp;
     }
     if (rep->nBtnsWanted > 0) {
-        if (((unsigned short) rep->firstBtnWanted + rep->nBtnsWanted)
-            >= devi->num_btns)
+        if (((unsigned short) rep->firstBtnWanted + rep->nBtnsWanted) > devi->num_btns)
             goto BAILOUT;
         act = &devi->btn_acts[rep->firstBtnWanted];
         bzero((char *) act, (rep->nBtnsWanted * sizeof(XkbAction)));
@@ -201,8 +200,7 @@ _XkbReadGetDeviceInfoReply(Display *dpy,
     if (rep->nBtnsRtrn > 0) {
         int size;
 
-        if (((unsigned short) rep->firstBtnRtrn + rep->nBtnsRtrn)
-            >= devi->num_btns)
+        if (((unsigned short) rep->firstBtnRtrn + rep->nBtnsRtrn) > devi->num_btns)
             goto BAILOUT;
         act = &devi->btn_acts[rep->firstBtnRtrn];
         size = rep->nBtnsRtrn * SIZEOF(xkbActionWireDesc);