diff --git a/dwmblocks.c b/dwmblocks.c
index 6589ae1..539823e 100644
--- a/dwmblocks.c
+++ b/dwmblocks.c
@@ -255,7 +255,7 @@ void
 writepid()
 {
         int fd;
-        char buf[20];
+        char buf[8]; /* maximum possible pid in linux is 4194304 */
         struct flock fl;
         ssize_t len;