Index: /trunk/ccl/lisp-kernel/pmcl-kernel.c
===================================================================
--- /trunk/ccl/lisp-kernel/pmcl-kernel.c	(revision 5611)
+++ /trunk/ccl/lisp-kernel/pmcl-kernel.c	(revision 5612)
@@ -1333,4 +1333,6 @@
   TCR *tcr = get_tcr(false);
   if (tcr) {
+    /* Some threads may be dying; no threads should be created. */
+    LOCK(lisp_global(TCR_AREA_LOCK),tcr);
     tcr->vs_area->active = tcr->vs_area->high - node_size;
     tcr->save_vsp = (LispObj *)(tcr->vs_area->active);