Index: cont.c 
=================================================================== 
--- cont.c	(revision 25392) 
+++ cont.c	(working copy) 
@@ -198,7 +198,8 @@ 
     if (ptr) {
 	rb_fiber_t *fib = ptr;
 
-	if (fib->cont.type != ROOT_FIBER_CONTEXT) {
+	if (fib->cont.type != ROOT_FIBER_CONTEXT &&
+	    fib->cont.saved_thread.local_storage) {
 	    st_free_table(fib->cont.saved_thread.local_storage);
 	}
 	fiber_link_remove(fib);
@@ -731,6 +732,7 @@ 
     cont_init(&fib->cont, th);
     fib->prev = Qnil;
     fib->status = CREATED;
+    fib->prev_fiber = fib->next_fiber = fib;
 
     DATA_PTR(fibval) = fib;
 
@@ -744,8 +746,6 @@ 
     rb_context_t *cont = &fib->cont;
     rb_thread_t *th = &cont->saved_thread;
 
-    fiber_link_join(fib);
-
     /* initialize cont */
     cont->vm_stack = 0;
 
@@ -753,6 +753,8 @@ 
     th->stack_size = FIBER_VM_STACK_SIZE;
     th->stack = ALLOC_N(VALUE, th->stack_size);
 
+    fiber_link_join(fib);
+
     th->cfp = (void *)(th->stack + th->stack_size);
     th->cfp--;
     th->cfp->pc = 0;