diff --git a/collects/tests/future/future.rkt b/collects/tests/future/future.rkt
index 85149cafb6..8e4a847b9c 100644
--- a/collects/tests/future/future.rkt
+++ b/collects/tests/future/future.rkt
@@ -635,7 +635,7 @@ We should also test deep continuations.
                        (fsemaphore-wait m)))] 
          [f2 (func (λ () 
                        (let* ([lst '()]
-                              [retval (let loop ([index 10000] [l lst]) 
+                              [retval (let loop ([index 100000] [l lst]) 
                                         (cond 
                                           [(zero? index) l] 
                                           [else 
diff --git a/src/racket/src/future.c b/src/racket/src/future.c
index 388c591751..5e9056b6b1 100644
--- a/src/racket/src/future.c
+++ b/src/racket/src/future.c
@@ -582,6 +582,12 @@ void scheme_init_futures_per_place()
   futures_init();
 }
 
+static Scheme_Object *set_fts_thread(Scheme_Object *ignored)
+{
+  scheme_future_thread_state->thread = scheme_current_thread;
+  return ignored;
+}
+
 void futures_init(void)
 {
   Scheme_Future_State *fs;
@@ -607,7 +613,8 @@ void futures_init(void)
   rt_fts->is_runtime_thread = 1;
   rt_fts->gen0_size = 1;
   scheme_future_thread_state = rt_fts;
-  rt_fts->thread = scheme_current_thread;
+  scheme_add_swap_callback(set_fts_thread, scheme_false);
+  set_fts_thread(scheme_false);
 
   REGISTER_SO(fs->future_queue);
   REGISTER_SO(fs->future_queue_end);
@@ -957,6 +964,12 @@ void scheme_future_check_custodians()
   scheme_future_continue_after_gc();
 }
 
+int scheme_future_is_runtime_thread()
+{
+  Scheme_Future_Thread_State *fts = scheme_future_thread_state;
+  return fts->is_runtime_thread;
+}
+
 /**********************************************************************/
 /* Future-event logging                                               */
 /**********************************************************************/
@@ -1420,8 +1433,7 @@ static void run_would_be_future(future_t *ft)
   fts = scheme_future_thread_state;
   
   /* Setup the future thread state */
-  fts->thread = p;
-  fts->thread->futures_slow_path_tracing++;
+  p->futures_slow_path_tracing++;
   scheme_use_rtcall++;
 
   savebuf = p->error_buf;
@@ -1435,7 +1447,7 @@ static void run_would_be_future(future_t *ft)
   }
 
   scheme_use_rtcall--;
-  fts->thread->futures_slow_path_tracing--;
+  p->futures_slow_path_tracing--;
   ft->in_tracing_mode = 0;
 
   p->error_buf = savebuf;
@@ -3590,7 +3602,7 @@ static void do_invoke_rtcall(Scheme_Future_State *fs, future_t *future)
           retval = _scheme_apply(arg_s0, future->arg_i0, arg_S0);
 
         future->retval_s = retval;
-        send_special_result(future, retval);        
+        send_special_result(future, retval);     
 
         break;
       }
diff --git a/src/racket/src/future.h b/src/racket/src/future.h
index 0f12d283b1..452f34626d 100644
--- a/src/racket/src/future.h
+++ b/src/racket/src/future.h
@@ -268,6 +268,7 @@ void scheme_future_continue_after_gc();
 void scheme_check_future_work();
 void scheme_future_gc_pause();
 void scheme_future_check_custodians();
+int scheme_future_is_runtime_thread();
 
 #endif /* MZ_USE_FUTURES */
 
diff --git a/src/racket/src/jitcall.c b/src/racket/src/jitcall.c
index 01a436e055..97f80683da 100644
--- a/src/racket/src/jitcall.c
+++ b/src/racket/src/jitcall.c
@@ -157,7 +157,10 @@ static Scheme_Object *ts__scheme_tail_apply_from_native(Scheme_Object *rator, in
     /* try thread-local allocation: */
     Scheme_Object **a;
 #ifdef MZ_PRECISE_GC
-    a = MALLOC_N(Scheme_Object *, argc);
+    if (scheme_future_is_runtime_thread())
+      a = NULL;
+    else
+      a = MALLOC_N(Scheme_Object *, argc);
 #else
     a = NULL; /* future-local allocation is not supported */
 #endif