diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/posix.c b/libraries/AP_HAL_ChibiOS/hwdef/common/posix.c
index 70b05cbf5f..2fbf2d4670 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/posix.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/posix.c
@@ -2548,6 +2548,7 @@ fprintf(FILE *fp, const char *fmt, ...)
             fputc(buf[i], fp);
         }
     } else {
+        va_end(va);
         return -1;
     }
     va_end(va);