diff --git a/kernel/printf.c b/kernel/printf.c
index e1347de..1a50203 100644
--- a/kernel/printf.c
+++ b/kernel/printf.c
@@ -109,6 +109,7 @@ printf(char *fmt, ...)
       break;
     }
   }
+  va_end(ap);
 
   if(locking)
     release(&pr.lock);