diff --git a/README b/README
index 5e2209e..e9772b4 100644
--- a/README
+++ b/README
@@ -142,6 +142,7 @@ KNOWN ISSUES
 - `{fputc,putc,putchar}_unlocked()` are not hooked when writing to stdout
   (which might be redirected to stderr). Can't be fixed as the compiler
   inlines the code into the program without calling any function.
+- Test `test_stdio.sh` fails for this reason on FreeBSD.
 
 
 BUGS