diff --git a/mx_proc.c b/mx_proc.c
index 72330df4..9f486b2d 100644
--- a/mx_proc.c
+++ b/mx_proc.c
@@ -137,7 +137,7 @@ int mx_proc_pid_stat_read(struct mx_proc_pid_stat *pps, char *fmt, ...)
     assert(pps);
 
     va_start(ap, fmt);
-    _mx_cleanup_free_ char *fname = fname = mx_vasprintf_forever(fmt, ap);
+    _mx_cleanup_free_ char *fname = mx_vasprintf_forever(fmt, ap);
     va_end(ap);
 
     res = mx_read_first_line_from_file(fname, &line);