diff --git a/src/racket/src/codetab.inc b/src/racket/src/codetab.inc
index c063c30065..fb66f2dded 100644
--- a/src/racket/src/codetab.inc
+++ b/src/racket/src/codetab.inc
@@ -22,9 +22,12 @@ extern MZ_DLLIMPORT int GC_is_marked(void *);
 
 THREAD_LOCAL_DECL(static void **codetab_tree);
 THREAD_LOCAL_DECL(static int during_set);
+
 #ifdef MZ_USE_PLACES
+/* This table is shared but not locked; we rely on x86-TSO
+   and the fact that entries are only added (never removed)
+   to skip the lock: */
 static void **shared_codetab_tree;
-static mzrt_rwlock *shared_codetab_lock;
 #endif
 
 static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing);
@@ -60,9 +63,7 @@ static void *find_symbol(uintptr_t v)
 
 #ifdef MZ_USE_PLACES
   if (!r && shared_codetab_tree) {
-    mzrt_rwlock_rdlock(shared_codetab_lock);
     r = do_find_symbol(shared_codetab_tree, v);
-    mzrt_rwlock_unlock(shared_codetab_lock);
   }
 #endif
 
@@ -99,13 +100,6 @@ void scheme_jit_add_symbol(uintptr_t start, uintptr_t end, void *value, int gc_a
 
 #ifdef MZ_USE_PLACES
   if (!gc_able) {
-    if (!shared_codetab_lock) {
-      /* this function will be called in the main place 
-         before others are started, so a lazy lock creation 
-         is ok */
-      mzrt_rwlock_create(&shared_codetab_lock);      
-    }
-    mzrt_rwlock_wrlock(shared_codetab_lock);
     if (!shared_codetab_tree)
       shared_codetab_tree = malloc_node(0);
     the_tree = shared_codetab_tree;
@@ -224,12 +218,6 @@ void scheme_jit_add_symbol(uintptr_t start, uintptr_t end, void *value, int gc_a
     do_clear_symbols(the_tree, start, 0, 0, 0);
   }
 #endif
-
-#ifdef MZ_USE_PLACES
-  if (!gc_able) {
-    mzrt_rwlock_unlock(shared_codetab_lock);      
-  }
-#endif
 }
 
 static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing)