diff --git a/proc/whattime.c b/proc/whattime.c
index f55f3636..c223cad6 100644
--- a/proc/whattime.c
+++ b/proc/whattime.c
@@ -38,7 +38,7 @@
 #include "whattime.h"
 #include "sysinfo.h"
 
-static char buf[128];
+static char buf[256];
 static double av[3];
 
 char *sprint_uptime(int human_readable) {
@@ -60,6 +60,7 @@ char *sprint_uptime(int human_readable) {
       realtime->tm_hour, realtime->tm_min, realtime->tm_sec);
   } else {
     pos = 0;
+    buf[0] = '\0';
   }
 
 /* read and calculate the amount of uptime */