From 6f1588fcac7fdd035754d915ea7ce1748da0cbd2 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 19 Sep 2013 16:56:01 -0500
Subject: [PATCH] fix custodian-limit checking for phantom byte strings

Closes PR 14036
---
 .../racket-pkgs/racket-test/tests/racket/will.rktl | 14 +++++++++++++-
 racket/src/racket/gc2/newgc.c                      | 10 ++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/pkgs/racket-pkgs/racket-test/tests/racket/will.rktl b/pkgs/racket-pkgs/racket-test/tests/racket/will.rktl
index b17f0c1cc4..c1289ee189 100644
--- a/pkgs/racket-pkgs/racket-test/tests/racket/will.rktl
+++ b/pkgs/racket-pkgs/racket-test/tests/racket/will.rktl
@@ -216,7 +216,19 @@
   (collect-garbage)
   (test #t < (current-memory-use) (+ m (expt 2 28)))
   (test #t < (current-memory-use c) (+ mc (expt 2 28)))
-  (semaphore-post s))
+  (semaphore-post s)
+
+  (let ([done? #f])
+    (sync
+     (let ([c (make-custodian)])
+       (parameterize ([current-custodian c])
+         (thread
+          (lambda ()
+            (custodian-limit-memory c 10000000)
+            (define b (make-phantom-bytes 100))
+            (set-phantom-bytes! b 0)
+            (set! done? #t))))))
+    (test #t values done?)))
 
 ;; ----------------------------------------
 ;; Check that local variables are cleared for space safety
diff --git a/racket/src/racket/gc2/newgc.c b/racket/src/racket/gc2/newgc.c
index 57870f8aff..40390bc567 100644
--- a/racket/src/racket/gc2/newgc.c
+++ b/racket/src/racket/gc2/newgc.c
@@ -1529,12 +1529,14 @@ uintptr_t add_no_overflow(uintptr_t a, uintptr_t b)
 
 int GC_allocate_phantom_bytes(intptr_t request_size_bytes)
 {
-#ifdef NEWGC_BTC_ACCOUNT
   NewGC *gc = GC_get_GC();
 
-  if (premaster_or_place_gc(gc)) {
-    if (BTC_single_allocation_limit(gc, request_size_bytes))
-      return 0;
+#ifdef NEWGC_BTC_ACCOUNT
+  if (request_size_bytes > 0) {
+    if (premaster_or_place_gc(gc)) {
+      if (BTC_single_allocation_limit(gc, request_size_bytes))
+        return 0;
+    }
   }
 #endif