diff --git a/Include/internal/pycore_mimalloc.h b/Include/internal/pycore_mimalloc.h
index 100f78d53021ee..d10b01d5b49b19 100644
--- a/Include/internal/pycore_mimalloc.h
+++ b/Include/internal/pycore_mimalloc.h
@@ -52,6 +52,7 @@ struct _mimalloc_thread_state {
     mi_heap_t *current_object_heap;
     mi_heap_t heaps[_Py_MIMALLOC_HEAP_COUNT];
     mi_tld_t tld;
+    int initialized;
     struct llist_node page_list;
 };
 #endif
diff --git a/Python/gc_free_threading.c b/Python/gc_free_threading.c
index e6bd012c40ee82..ac041991ff6d9e 100644
--- a/Python/gc_free_threading.c
+++ b/Python/gc_free_threading.c
@@ -252,6 +252,10 @@ gc_visit_heaps_lock_held(PyInterpreterState *interp, mi_block_visit_fun *visitor
     // visit each thread's heaps for GC objects
     for (PyThreadState *p = interp->threads.head; p != NULL; p = p->next) {
         struct _mimalloc_thread_state *m = &((_PyThreadStateImpl *)p)->mimalloc;
+        if (!_Py_atomic_load_int(&m->initialized)) {
+            // The thread may not have called tstate_mimalloc_bind() yet.
+            continue;
+        }
 
         arg->offset = offset_base;
         if (!mi_heap_visit_blocks(&m->heaps[_Py_MIMALLOC_HEAP_GC], true,
diff --git a/Python/pystate.c b/Python/pystate.c
index 36e4206b4a282e..d524d3d1768872 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -3076,6 +3076,8 @@ tstate_mimalloc_bind(PyThreadState *tstate)
     // _PyObject_GC_New() and similar functions temporarily override this to
     // use one of the GC heaps.
     mts->current_object_heap = &mts->heaps[_Py_MIMALLOC_HEAP_OBJECT];
+
+    _Py_atomic_store_int(&mts->initialized, 1);
 #endif
 }
 
diff --git a/Tools/tsan/suppressions_free_threading.txt b/Tools/tsan/suppressions_free_threading.txt
index f855e9ce2698a5..f5b4f04bd54fd7 100644
--- a/Tools/tsan/suppressions_free_threading.txt
+++ b/Tools/tsan/suppressions_free_threading.txt
@@ -29,7 +29,6 @@ race:_PyParkingLot_Park
 
 race_top:_add_to_weak_set
 race_top:_in_weak_set
-race_top:_mi_heap_delayed_free_partial
 race_top:_PyEval_EvalFrameDefault
 race_top:_PyImport_AcquireLock
 race_top:_PyImport_ReleaseLock
@@ -39,7 +38,6 @@ race_top:_PyType_HasFeature
 race_top:assign_version_tag
 race_top:insertdict
 race_top:lookup_tp_dict
-race_top:mi_heap_visit_pages
 race_top:PyMember_GetOne
 race_top:PyMember_SetOne
 race_top:new_reference
@@ -71,7 +69,6 @@ race_top:_Py_slot_tp_getattr_hook
 race_top:add_threadstate
 race_top:dump_traceback
 race_top:fatal_error
-race_top:mi_page_decode_padding
 race_top:_multiprocessing_SemLock_release_impl
 race_top:_PyFrame_GetCode
 race_top:_PyFrame_Initialize