diff --git a/hw/xfree86/os-support/linux/lnx_video.c b/hw/xfree86/os-support/linux/lnx_video.c
index a24fce37b..fd83022f6 100644
--- a/hw/xfree86/os-support/linux/lnx_video.c
+++ b/hw/xfree86/os-support/linux/lnx_video.c
@@ -119,7 +119,7 @@ hwEnableIO(void)
     short i;
     size_t n=0;
     int begin, end;
-    char *buf=NULL, target[4];
+    char *buf=NULL, target[5];
     FILE *fp;
 
     if (ioperm(0, 1024, 1)) {
@@ -129,6 +129,8 @@ hwEnableIO(void)
     }
 
 #if !defined(__alpha__)
+    target[4] = '\0';
+
     /* trap access to the keyboard controller(s) and timer chip(s) */
     fp = fopen("/proc/ioports", "r");
     while (getline(&buf, &n, fp) != -1) {